chore(deps): update dependency @napi-rs/cli to v3.10.0 (#26690)

This PR contains the following updates:

| Package | Change |
[Age](https://docs.renovatebot.com/merge-confidence/) |
[Adoption](https://docs.renovatebot.com/merge-confidence/) |
[Passing](https://docs.renovatebot.com/merge-confidence/) |
[Confidence](https://docs.renovatebot.com/merge-confidence/) | Type |
Update |
|---|---|---|---|---|---|---|---|
| [@napi-rs/cli](https://napi.rs/)
([source](https://redirect.github.com/napi-rs/napi-rs)) | [`3.9.1` →
`3.10.1`](https://renovatebot.com/diffs/npm/@napi-rs%2fcli/3.9.1/3.10.1)
|
![age](https://developer.mend.io/api/mc/badges/age/npm/@napi-rs%2fcli/3.10.1?slim=true)
|
![adoption](https://developer.mend.io/api/mc/badges/adoption/npm/@napi-rs%2fcli/3.10.1?slim=true)
|
![passing](https://developer.mend.io/api/mc/badges/compatibility/npm/@napi-rs%2fcli/3.9.1/3.10.1?slim=true)
|
![confidence](https://developer.mend.io/api/mc/badges/confidence/npm/@napi-rs%2fcli/3.9.1/3.10.1?slim=true)
| pnpm.catalog.default | minor |
| [napi](https://redirect.github.com/napi-rs/napi-rs) | `3.12.4` →
`3.12.5` |
![age](https://developer.mend.io/api/mc/badges/age/crate/napi/3.12.5?slim=true)
|
![adoption](https://developer.mend.io/api/mc/badges/adoption/crate/napi/3.12.5?slim=true)
|
![passing](https://developer.mend.io/api/mc/badges/compatibility/crate/napi/3.12.4/3.12.5?slim=true)
|
![confidence](https://developer.mend.io/api/mc/badges/confidence/crate/napi/3.12.4/3.12.5?slim=true)
| workspace.dependencies | patch |
| [napi-derive](https://redirect.github.com/napi-rs/napi-rs) | `3.6.5` →
`3.6.6` |
![age](https://developer.mend.io/api/mc/badges/age/crate/napi-derive/3.6.6?slim=true)
|
![adoption](https://developer.mend.io/api/mc/badges/adoption/crate/napi-derive/3.6.6?slim=true)
|
![passing](https://developer.mend.io/api/mc/badges/compatibility/crate/napi-derive/3.6.5/3.6.6?slim=true)
|
![confidence](https://developer.mend.io/api/mc/badges/confidence/crate/napi-derive/3.6.5/3.6.6?slim=true)
| workspace.dependencies | patch |

---

### Release Notes

<details>
<summary>napi-rs/napi-rs (@&#8203;napi-rs/cli)</summary>

###
[`v3.10.1`](https://redirect.github.com/napi-rs/napi-rs/compare/@napi-rs/cli@3.10.0...@napi-rs/cli@3.10.1)

[Compare
Source](https://redirect.github.com/napi-rs/napi-rs/compare/@napi-rs/cli@3.10.0...@napi-rs/cli@3.10.1)

###
[`v3.10.0`](https://redirect.github.com/napi-rs/napi-rs/compare/@napi-rs/cli@3.9.1...@napi-rs/cli@3.10.0)

[Compare
Source](https://redirect.github.com/napi-rs/napi-rs/compare/@napi-rs/cli@3.9.1...@napi-rs/cli@3.10.0)

</details>

---

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---

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---

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View the [repository job
log](https://developer.mend.io/github/oxc-project/oxc).

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Cargo.lock

@@ -1401,9 +1401,9 @@ dependencies = [
 
 [[package]]
 name = "napi"
-version = "3.12.4"
+version = "3.12.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3d2c1d080c842ec1347ebf3cfb9347c15f8c2262f143cc30eea41ddf1c7da720"
+checksum = "f0c007d4a8ead952a81887661d41fd56b7e7a70d3d4d921f445fb37a8f6efa1e"
 dependencies = [
  "bitflags",
  "ctor",
@@ -1426,9 +1426,9 @@ checksum = "860e7c40864f95cfb83cde99f9ebadd88ef3d9bdccd7dd2cee0cc96a2dd4ffa7"
 
 [[package]]
 name = "napi-derive"
-version = "3.6.5"
+version = "3.6.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "350057056a30368aa76c11a0d406b0aa61321710be2c36656ab4f6efe0b785a2"
+checksum = "e8872852c2d050fc5859749864119bc5d50e3f6ad5957874d61d1a07c76771cb"
 dependencies = [
  "convert_case",
  "ctor",

apps/oxfmt/src-js/bindings.d.ts

@@ -1,6 +1,14 @@
 /* auto-generated by NAPI-RS */
 /* eslint-disable */
 
+/**
+ * Which binding artifact the generated loader actually loaded: `'native'` for
+ * a native addon, otherwise the `platformArchABI` of the WASI flavor. Every
+ * flavor napi-rs can build is listed, because `NAPI_RS_NATIVE_LIBRARY_PATH`
+ * can point the loader at a WASI artifact this package does not build itself.
+ */
+export declare const __napiBindingTarget: 'native' | 'wasm32-wasi' | 'wasm32-wasip1'
+
 export interface Comment {
   type: 'Line' | 'Block'
   value: string

apps/oxfmt/src-js/bindings.js

@@ -7,6 +7,10 @@ const require = createRequire(import.meta.url)
 
 const { readFileSync } = require('fs')
 let nativeBinding = null
+// Which artifact actually loaded. The WASI fallback chain overwrites it with
+// the flavor it resolved; the late native retry below leaves it alone because
+// it only runs while no WASI candidate has been loaded.
+let __napiLoadedBindingTarget = 'native'
 const loadErrors = []
 
 const isMusl = () => {
@@ -65,7 +69,16 @@ const isMuslFromChildProcess = () => {
 function requireNative() {
   if (process.env.NAPI_RS_NATIVE_LIBRARY_PATH) {
     try {
-      return require(process.env.NAPI_RS_NATIVE_LIBRARY_PATH)
+      const overrideBinding = require(process.env.NAPI_RS_NATIVE_LIBRARY_PATH)
+      // The override may be a generated WASI loader, which already reports its
+      // own flavor. Adopt it: `module.exports` aliases this object, so claiming
+      // 'native' would both misreport the artifact and overwrite the loader's
+      // marker through the alias.
+      __napiLoadedBindingTarget =
+        overrideBinding && typeof overrideBinding.__napiBindingTarget === 'string'
+          ? overrideBinding.__napiBindingTarget
+          : 'native'
+      return overrideBinding
     } catch (err) {
       loadErrors.push(err)
     }
@@ -630,6 +643,7 @@ if (!nativeBinding || forceWasi) {
       if (!candidateFailed) {
         wasiBinding = require('./oxfmt.wasi.cjs')
         nativeBinding = wasiBinding
+        __napiLoadedBindingTarget = 'wasm32-wasi'
         wasiBindingLoaded = true
       }
     } catch (err) {
@@ -656,6 +670,7 @@ if (!nativeBinding || forceWasi) {
         }
         wasiBinding = require('@oxfmt/binding-wasm32-wasi')
         nativeBinding = wasiBinding
+        __napiLoadedBindingTarget = 'wasm32-wasi'
         wasiBindingLoaded = true
       }
     } catch (err) {
@@ -706,3 +721,4 @@ export { Severity }
 export { format }
 export { jsTextToDoc }
 export { runCli }
+export const __napiBindingTarget = __napiLoadedBindingTarget

apps/oxlint/src-js/bindings.d.ts

@@ -1,6 +1,14 @@
 /* auto-generated by NAPI-RS */
 /* eslint-disable */
 
+/**
+ * Which binding artifact the generated loader actually loaded: `'native'` for
+ * a native addon, otherwise the `platformArchABI` of the WASI flavor. Every
+ * flavor napi-rs can build is listed, because `NAPI_RS_NATIVE_LIBRARY_PATH`
+ * can point the loader at a WASI artifact this package does not build itself.
+ */
+export declare const __napiBindingTarget: 'native' | 'wasm32-wasi' | 'wasm32-wasip1'
+
 export interface Comment {
   type: 'Line' | 'Block'
   value: string

apps/oxlint/src-js/bindings.js

@@ -7,6 +7,10 @@ const require = createRequire(import.meta.url)
 
 const { readFileSync } = require('fs')
 let nativeBinding = null
+// Which artifact actually loaded. The WASI fallback chain overwrites it with
+// the flavor it resolved; the late native retry below leaves it alone because
+// it only runs while no WASI candidate has been loaded.
+let __napiLoadedBindingTarget = 'native'
 const loadErrors = []
 
 const isMusl = () => {
@@ -65,7 +69,16 @@ const isMuslFromChildProcess = () => {
 function requireNative() {
   if (process.env.NAPI_RS_NATIVE_LIBRARY_PATH) {
     try {
-      return require(process.env.NAPI_RS_NATIVE_LIBRARY_PATH)
+      const overrideBinding = require(process.env.NAPI_RS_NATIVE_LIBRARY_PATH)
+      // The override may be a generated WASI loader, which already reports its
+      // own flavor. Adopt it: `module.exports` aliases this object, so claiming
+      // 'native' would both misreport the artifact and overwrite the loader's
+      // marker through the alias.
+      __napiLoadedBindingTarget =
+        overrideBinding && typeof overrideBinding.__napiBindingTarget === 'string'
+          ? overrideBinding.__napiBindingTarget
+          : 'native'
+      return overrideBinding
     } catch (err) {
       loadErrors.push(err)
     }
@@ -630,6 +643,7 @@ if (!nativeBinding || forceWasi) {
       if (!candidateFailed) {
         wasiBinding = require('./oxlint.wasi.cjs')
         nativeBinding = wasiBinding
+        __napiLoadedBindingTarget = 'wasm32-wasi'
         wasiBindingLoaded = true
       }
     } catch (err) {
@@ -656,6 +670,7 @@ if (!nativeBinding || forceWasi) {
         }
         wasiBinding = require('@oxlint/binding-wasm32-wasi')
         nativeBinding = wasiBinding
+        __napiLoadedBindingTarget = 'wasm32-wasi'
         wasiBindingLoaded = true
       }
     } catch (err) {
@@ -708,3 +723,4 @@ export { getBufferOffset }
 export { lint }
 export { parseRawSync }
 export { rawTransferSupported }
+export const __napiBindingTarget = __napiLoadedBindingTarget

napi/minify/index.d.ts

@@ -1,6 +1,14 @@
 /* auto-generated by NAPI-RS */
 /* eslint-disable */
 
+/**
+ * Which binding artifact the generated loader actually loaded: `'native'` for
+ * a native addon, otherwise the `platformArchABI` of the WASI flavor. Every
+ * flavor napi-rs can build is listed, because `NAPI_RS_NATIVE_LIBRARY_PATH`
+ * can point the loader at a WASI artifact this package does not build itself.
+ */
+export declare const __napiBindingTarget: 'native' | 'wasm32-wasi' | 'wasm32-wasip1'
+
 export interface CodegenOptions {
   /**
    * Remove whitespace.

napi/minify/index.js

@@ -7,6 +7,10 @@ const require = createRequire(import.meta.url)
 
 const { readFileSync } = require('fs')
 let nativeBinding = null
+// Which artifact actually loaded. The WASI fallback chain overwrites it with
+// the flavor it resolved; the late native retry below leaves it alone because
+// it only runs while no WASI candidate has been loaded.
+let __napiLoadedBindingTarget = 'native'
 const loadErrors = []
 
 const isMusl = () => {
@@ -65,7 +69,16 @@ const isMuslFromChildProcess = () => {
 function requireNative() {
   if (process.env.NAPI_RS_NATIVE_LIBRARY_PATH) {
     try {
-      return require(process.env.NAPI_RS_NATIVE_LIBRARY_PATH)
+      const overrideBinding = require(process.env.NAPI_RS_NATIVE_LIBRARY_PATH)
+      // The override may be a generated WASI loader, which already reports its
+      // own flavor. Adopt it: `module.exports` aliases this object, so claiming
+      // 'native' would both misreport the artifact and overwrite the loader's
+      // marker through the alias.
+      __napiLoadedBindingTarget =
+        overrideBinding && typeof overrideBinding.__napiBindingTarget === 'string'
+          ? overrideBinding.__napiBindingTarget
+          : 'native'
+      return overrideBinding
     } catch (err) {
       loadErrors.push(err)
     }
@@ -630,6 +643,7 @@ if (!nativeBinding || forceWasi) {
       if (!candidateFailed) {
         wasiBinding = require('./minify.wasi.cjs')
         nativeBinding = wasiBinding
+        __napiLoadedBindingTarget = 'wasm32-wasi'
         wasiBindingLoaded = true
       }
     } catch (err) {
@@ -656,6 +670,7 @@ if (!nativeBinding || forceWasi) {
         }
         wasiBinding = require('@oxc-minify/binding-wasm32-wasi')
         nativeBinding = wasiBinding
+        __napiLoadedBindingTarget = 'wasm32-wasi'
         wasiBindingLoaded = true
       }
     } catch (err) {
@@ -714,3 +729,4 @@ export { LegalCommentsMode }
 export { minify }
 export { minifySync }
 export { Severity }
+export const __napiBindingTarget = __napiLoadedBindingTarget

napi/minify/minify.wasi-browser.js

@@ -8,6 +8,55 @@ import {
 import { createContext as __emnapiCreateContext } from '@emnapi/runtime'
 
 
+export const __napiBindingTarget = 'wasm32-wasi'
+function __napiStampBindingTarget(exportsObject, target) {
+  if (
+    Object.prototype.hasOwnProperty.call(exportsObject, '__napiBindingTarget')
+  ) {
+    if (exportsObject.__napiBindingTarget === target) {
+      // Already ours: the root entry aliases the object it loaded, so a WASI
+      // fallback candidate — or a `NAPI_RS_NATIVE_LIBRARY_PATH` override that
+      // is a generated loader — arrives already stamped with this same value.
+      return target
+    }
+    const error = new Error(
+      '`__napiBindingTarget` is reserved by the generated binding loader, but the loaded binding already exports it. Rename the export, e.g. #[napi(js_name = "...")].',
+    )
+    error.code = 'ERR_NAPI_BINDING_TARGET_CONFLICT'
+    throw error
+  }
+  if (!Object.isExtensible(exportsObject)) {
+    // A `#[napi(module_exports)]` hook may seal or freeze this object
+    // (`Object::seal` / `Object::freeze`). Reporting the artifact is metadata,
+    // never a reason to fail an otherwise successful load, so the stamp is
+    // skipped. What a consumer still sees then follows the entry point: the
+    // browser and deferred loaders declare `__napiBindingTarget` at module
+    // level and go on reporting it, while the CommonJS entries hand back this
+    // very object as `module.exports`, so there the value is absent.
+    return target
+  }
+  try {
+    // [[Define]], not [[Set]]: an ordinary assignment walks the prototype
+    // chain, so an inherited accessor could swallow the value or throw and
+    // fail an otherwise successful load. The descriptor is what a successful
+    // assignment would have produced.
+    Object.defineProperty(exportsObject, '__napiBindingTarget', {
+      configurable: true,
+      enumerable: true,
+      value: target,
+      writable: true,
+    })
+  } catch {
+    // Same rule as the non-extensible skip above: reporting the artifact is
+    // metadata, never a reason to fail an otherwise successful load. An exotic
+    // object (a Proxy whose defineProperty trap refuses) is skipped, not
+    // thrown over.
+  }
+  // The CommonJS loaders assign this return value so `cjs-module-lexer` — and
+  // therefore Node's CJS -> ESM named export detection — can see
+  // `__napiBindingTarget` statically.
+  return target
+}
 
 const __wasi = new __WASI({
   version: 'preview1',
@@ -42,10 +91,40 @@ let __emnapiContext
 
 const __wasiDisposeSymbol = Symbol.for('napi.rs.wasi.dispose')
 const __wasiWorkers = new Set()
+// The thread manager has to be reachable *before* anything that can throw
+// during load or registration. Initialization can fail after the pool has
+// already spawned workers, and the rollback still has to mark their
+// terminations as expected — but `__napiModule` is assigned only when
+// instantiation RETURNS, so on exactly that path it is still undefined. A
+// plugin factory runs while the emnapi module is being created, before the
+// wasm is loaded and before any registration function runs, and its context
+// carries the very same manager instance.
+let __wasiThreadManager
+
+function __captureWasiThreadManager(context) {
+  if (context && context.PThread) {
+    __wasiThreadManager = context.PThread
+  }
+  return {}
+}
+
+function __getWasiThreadManager() {
+  const manager =
+    __wasiThreadManager !== undefined
+      ? __wasiThreadManager
+      : __napiModule
+        ? __napiModule.PThread
+        : undefined
+  if (manager && typeof manager.terminateWorker === 'function') {
+    return manager
+  }
+  return undefined
+}
 let __napiInstance
 let __emnapiContextDestroyed = false
 let __emnapiContextDestroyPromise
 let __emnapiWasmEnvCleanupPrepared = false
+let __emnapiWasmEnvCleanupPreparing = false
 let __emnapiWasmEnvCleanupRan = false
 let __emnapiWasmEnvCleanupDrained = false
 let __emnapiWasmEnvCleanupDrainPromise
@@ -119,13 +198,58 @@ function __attachCleanupErrors(error, cleanupErrors) {
   return aggregate
 }
 
+function __wrapEmnapiContextDestroyForSettlement(
+  context,
+  prepareEnvCleanup,
+  isPreparingEnvCleanup,
+) {
+  let destroy
+  try {
+    destroy = context.destroy
+  } catch {
+    return context
+  }
+  if (typeof destroy !== 'function') {
+    return context
+  }
+  try {
+    Object.defineProperty(context, 'destroy', {
+      configurable: true,
+      enumerable: false,
+      writable: true,
+      value: function () {
+        // Reentered from a promise hook that fired inside the barrier: the
+        // frame running it destroys as soon as it returns.
+        if (isPreparingEnvCleanup?.()) {
+          return
+        }
+        prepareEnvCleanup?.()
+        return Reflect.apply(destroy, this, arguments)
+      },
+    })
+  } catch {}
+  return context
+}
+
+function __isPreparingWasmEnvCleanup() {
+  return __emnapiWasmEnvCleanupPreparing
+}
+
 function __prepareWasmEnvCleanup() {
-  if (__emnapiWasmEnvCleanupPrepared) {
+  if (__emnapiWasmEnvCleanupPrepared || __emnapiWasmEnvCleanupPreparing) {
     return
   }
   const prepare = __napiInstance?.exports?.napi_prepare_wasm_env_cleanup
   if (typeof prepare === 'function') {
-    prepare()
+    // The addon settles the promises it cancels synchronously, under a
+    // non-reentrant lifecycle mutex: anything a promise hook calls from in
+    // here must not reach this export again.
+    __emnapiWasmEnvCleanupPreparing = true
+    try {
+      prepare()
+    } finally {
+      __emnapiWasmEnvCleanupPreparing = false
+    }
     __emnapiWasmEnvCleanupRan = true
   }
   __emnapiWasmEnvCleanupPrepared = true
@@ -318,13 +442,80 @@ function __destroyEmnapiContext() {
   return destroyPromise
 }
 
+/**
+ * Holds the event loop open until `work` settles.
+ *
+ * Nothing else can: the pool workers are deliberately unreferenced so an idle
+ * binding cannot keep a process alive, and referencing them again for the
+ * termination does not hold either — emnapi unreferences a worker the moment it
+ * reports `async-thread-ready`, which for a worker that was still starting
+ * lands *after* the termination began. Without a handle of its own, an
+ * `await dispose()` with nothing else pending exits the process with its
+ * promise unsettled, and everything after the `await` is skipped.
+ *
+ * The timer is cleared as soon as the work settles, so this never outlives the
+ * disposal that asked for it.
+ */
+function __keepEventLoopAliveUntil(work) {
+  const setTimer = globalThis.setInterval
+  const clearTimer = globalThis.clearInterval
+  if (typeof setTimer !== 'function' || typeof clearTimer !== 'function') {
+    return work
+  }
+  let timer
+  try {
+    timer = setTimer(function () {}, 50)
+  } catch {
+    return work
+  }
+  const release = function () {
+    try {
+      clearTimer(timer)
+    } catch {}
+  }
+  return work.then(
+    (value) => {
+      release()
+      return value
+    },
+    (error) => {
+      release()
+      throw error
+    },
+  )
+}
+
+/**
+ * `@emnapi/wasi-threads` counts a worker exit as expected only when its own
+ * thread manager performed the termination. A bare `worker.terminate()` reaches
+ * the manager's `exit` listener instead, which reports
+ * `worker (tid = N) sent an error! ... stopped with exit code 1` and rethrows
+ * inside the emit — aborting the `once('exit')` that backs the terminate
+ * promise, so disposal never settles and the process dies with an uncaught
+ * exception. Mark the termination through the manager first.
+ *
+ * The manager comes from `__getWasiThreadManager`, not from `__napiModule`:
+ * the initialization rollback runs on the one path where instantiation never
+ * returned, so `__napiModule` is still undefined there while the workers it
+ * spawned are already registered and loaded.
+ *
+ * Not `terminateAllThreads()`: that one recreates the pool it just shut down.
+ */
 function __terminateWasiWorkers() {
   const cleanupErrors = []
   const pending = []
+  const threadManager = __getWasiThreadManager()
 
   for (const worker of __wasiWorkers) {
     let result
     try {
+      if (threadManager) {
+        threadManager.terminateWorker(worker)
+        // `terminateWorker` leaves behind a reporter that logs every message
+        // still queued on the port, which Node flushes on exit. Nothing is
+        // listening for those any more.
+        worker.onmessage = undefined
+      }
       result = worker.terminate()
     } catch (error) {
       cleanupErrors.push(error)
@@ -354,7 +545,9 @@ function __terminateWasiWorkers() {
       )
     }
   }
-  return pending.length > 0 ? Promise.all(pending).then(finish) : finish()
+  return pending.length > 0
+    ? __keepEventLoopAliveUntil(Promise.all(pending)).then(finish)
+    : finish()
 }
 
 function __finishWasiDisposal() {
@@ -555,7 +748,11 @@ let __wasiModule
 let __napiModule
 
 try {
-  __emnapiContext = __emnapiCreateContext({ autoDestroy: false })
+  __emnapiContext = __wrapEmnapiContextDestroyForSettlement(
+    __emnapiCreateContext({ autoDestroy: false }),
+    __prepareWasmEnvCleanup,
+    __isPreparingWasmEnvCleanup,
+  )
   __emnapiContext.suppressDestroy()
   
   ;({
@@ -566,7 +763,7 @@ try {
     context: __emnapiContext,
     asyncWorkPoolSize: __asyncWorkPoolSize,
     reuseWorker: false,
-    plugins: [__emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
+    plugins: [__captureWasiThreadManager, __emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
     wasi: __wasi,
     onCreateWorker() {
       const worker = new Worker(new URL('./wasi-worker-browser.mjs', import.meta.url), {
@@ -596,6 +793,12 @@ try {
     },
   }))
   __publishWasiDispose(__napiModule.exports)
+  // The default export hands out this object; a named module export does not
+  // travel with it, so carry the marker on the binding itself too. After the
+  // host install, which hands the same object to addon-provided registration
+  // functions that may put anything on it, and inside this `try`, so a claimed
+  // name fails the load through the rollback below rather than past it.
+  __napiStampBindingTarget(__napiModule.exports, __napiBindingTarget)
 } catch (error) {
   const cleanupErrors = await __rollbackWasiInitialization()
   throw __attachCleanupErrors(error, cleanupErrors)

napi/minify/minify.wasi.cjs

@@ -2,6 +2,56 @@
 /* eslint-disable */
 /* auto-generated by NAPI-RS */
 
+const __napiBindingTarget = 'wasm32-wasi'
+function __napiStampBindingTarget(exportsObject, target) {
+  if (
+    Object.prototype.hasOwnProperty.call(exportsObject, '__napiBindingTarget')
+  ) {
+    if (exportsObject.__napiBindingTarget === target) {
+      // Already ours: the root entry aliases the object it loaded, so a WASI
+      // fallback candidate — or a `NAPI_RS_NATIVE_LIBRARY_PATH` override that
+      // is a generated loader — arrives already stamped with this same value.
+      return target
+    }
+    const error = new Error(
+      '`__napiBindingTarget` is reserved by the generated binding loader, but the loaded binding already exports it. Rename the export, e.g. #[napi(js_name = "...")].',
+    )
+    error.code = 'ERR_NAPI_BINDING_TARGET_CONFLICT'
+    throw error
+  }
+  if (!Object.isExtensible(exportsObject)) {
+    // A `#[napi(module_exports)]` hook may seal or freeze this object
+    // (`Object::seal` / `Object::freeze`). Reporting the artifact is metadata,
+    // never a reason to fail an otherwise successful load, so the stamp is
+    // skipped. What a consumer still sees then follows the entry point: the
+    // browser and deferred loaders declare `__napiBindingTarget` at module
+    // level and go on reporting it, while the CommonJS entries hand back this
+    // very object as `module.exports`, so there the value is absent.
+    return target
+  }
+  try {
+    // [[Define]], not [[Set]]: an ordinary assignment walks the prototype
+    // chain, so an inherited accessor could swallow the value or throw and
+    // fail an otherwise successful load. The descriptor is what a successful
+    // assignment would have produced.
+    Object.defineProperty(exportsObject, '__napiBindingTarget', {
+      configurable: true,
+      enumerable: true,
+      value: target,
+      writable: true,
+    })
+  } catch {
+    // Same rule as the non-extensible skip above: reporting the artifact is
+    // metadata, never a reason to fail an otherwise successful load. An exotic
+    // object (a Proxy whose defineProperty trap refuses) is skipped, not
+    // thrown over.
+  }
+  // The CommonJS loaders assign this return value so `cjs-module-lexer` — and
+  // therefore Node's CJS -> ESM named export detection — can see
+  // `__napiBindingTarget` statically.
+  return target
+}
+
 const __nodeFs = require('node:fs')
 const __nodePath = require('node:path')
 const { WASI: __nodeWASI } = require('node:wasi')
@@ -149,10 +199,40 @@ let __emnapiContext
 
 const __wasiDisposeSymbol = Symbol.for('napi.rs.wasi.dispose')
 const __wasiWorkers = new Set()
+// The thread manager has to be reachable *before* anything that can throw
+// during load or registration. Initialization can fail after the pool has
+// already spawned workers, and the rollback still has to mark their
+// terminations as expected — but `__napiModule` is assigned only when
+// instantiation RETURNS, so on exactly that path it is still undefined. A
+// plugin factory runs while the emnapi module is being created, before the
+// wasm is loaded and before any registration function runs, and its context
+// carries the very same manager instance.
+let __wasiThreadManager
+
+function __captureWasiThreadManager(context) {
+  if (context && context.PThread) {
+    __wasiThreadManager = context.PThread
+  }
+  return {}
+}
+
+function __getWasiThreadManager() {
+  const manager =
+    __wasiThreadManager !== undefined
+      ? __wasiThreadManager
+      : __napiModule
+        ? __napiModule.PThread
+        : undefined
+  if (manager && typeof manager.terminateWorker === 'function') {
+    return manager
+  }
+  return undefined
+}
 let __napiInstance
 let __emnapiContextDestroyed = false
 let __emnapiContextDestroyPromise
 let __emnapiWasmEnvCleanupPrepared = false
+let __emnapiWasmEnvCleanupPreparing = false
 let __emnapiWasmEnvCleanupRan = false
 let __emnapiWasmEnvCleanupDrained = false
 let __emnapiWasmEnvCleanupDrainPromise
@@ -226,13 +306,58 @@ function __attachCleanupErrors(error, cleanupErrors) {
   return aggregate
 }
 
+function __wrapEmnapiContextDestroyForSettlement(
+  context,
+  prepareEnvCleanup,
+  isPreparingEnvCleanup,
+) {
+  let destroy
+  try {
+    destroy = context.destroy
+  } catch {
+    return context
+  }
+  if (typeof destroy !== 'function') {
+    return context
+  }
+  try {
+    Object.defineProperty(context, 'destroy', {
+      configurable: true,
+      enumerable: false,
+      writable: true,
+      value: function () {
+        // Reentered from a promise hook that fired inside the barrier: the
+        // frame running it destroys as soon as it returns.
+        if (isPreparingEnvCleanup?.()) {
+          return
+        }
+        prepareEnvCleanup?.()
+        return Reflect.apply(destroy, this, arguments)
+      },
+    })
+  } catch {}
+  return context
+}
+
+function __isPreparingWasmEnvCleanup() {
+  return __emnapiWasmEnvCleanupPreparing
+}
+
 function __prepareWasmEnvCleanup() {
-  if (__emnapiWasmEnvCleanupPrepared) {
+  if (__emnapiWasmEnvCleanupPrepared || __emnapiWasmEnvCleanupPreparing) {
     return
   }
   const prepare = __napiInstance?.exports?.napi_prepare_wasm_env_cleanup
   if (typeof prepare === 'function') {
-    prepare()
+    // The addon settles the promises it cancels synchronously, under a
+    // non-reentrant lifecycle mutex: anything a promise hook calls from in
+    // here must not reach this export again.
+    __emnapiWasmEnvCleanupPreparing = true
+    try {
+      prepare()
+    } finally {
+      __emnapiWasmEnvCleanupPreparing = false
+    }
     __emnapiWasmEnvCleanupRan = true
   }
   __emnapiWasmEnvCleanupPrepared = true
@@ -425,13 +550,80 @@ function __destroyEmnapiContext() {
   return destroyPromise
 }
 
+/**
+ * Holds the event loop open until `work` settles.
+ *
+ * Nothing else can: the pool workers are deliberately unreferenced so an idle
+ * binding cannot keep a process alive, and referencing them again for the
+ * termination does not hold either — emnapi unreferences a worker the moment it
+ * reports `async-thread-ready`, which for a worker that was still starting
+ * lands *after* the termination began. Without a handle of its own, an
+ * `await dispose()` with nothing else pending exits the process with its
+ * promise unsettled, and everything after the `await` is skipped.
+ *
+ * The timer is cleared as soon as the work settles, so this never outlives the
+ * disposal that asked for it.
+ */
+function __keepEventLoopAliveUntil(work) {
+  const setTimer = globalThis.setInterval
+  const clearTimer = globalThis.clearInterval
+  if (typeof setTimer !== 'function' || typeof clearTimer !== 'function') {
+    return work
+  }
+  let timer
+  try {
+    timer = setTimer(function () {}, 50)
+  } catch {
+    return work
+  }
+  const release = function () {
+    try {
+      clearTimer(timer)
+    } catch {}
+  }
+  return work.then(
+    (value) => {
+      release()
+      return value
+    },
+    (error) => {
+      release()
+      throw error
+    },
+  )
+}
+
+/**
+ * `@emnapi/wasi-threads` counts a worker exit as expected only when its own
+ * thread manager performed the termination. A bare `worker.terminate()` reaches
+ * the manager's `exit` listener instead, which reports
+ * `worker (tid = N) sent an error! ... stopped with exit code 1` and rethrows
+ * inside the emit — aborting the `once('exit')` that backs the terminate
+ * promise, so disposal never settles and the process dies with an uncaught
+ * exception. Mark the termination through the manager first.
+ *
+ * The manager comes from `__getWasiThreadManager`, not from `__napiModule`:
+ * the initialization rollback runs on the one path where instantiation never
+ * returned, so `__napiModule` is still undefined there while the workers it
+ * spawned are already registered and loaded.
+ *
+ * Not `terminateAllThreads()`: that one recreates the pool it just shut down.
+ */
 function __terminateWasiWorkers() {
   const cleanupErrors = []
   const pending = []
+  const threadManager = __getWasiThreadManager()
 
   for (const worker of __wasiWorkers) {
     let result
     try {
+      if (threadManager) {
+        threadManager.terminateWorker(worker)
+        // `terminateWorker` leaves behind a reporter that logs every message
+        // still queued on the port, which Node flushes on exit. Nothing is
+        // listening for those any more.
+        worker.onmessage = undefined
+      }
       result = worker.terminate()
     } catch (error) {
       cleanupErrors.push(error)
@@ -461,7 +653,9 @@ function __terminateWasiWorkers() {
       )
     }
   }
-  return pending.length > 0 ? Promise.all(pending).then(finish) : finish()
+  return pending.length > 0
+    ? __keepEventLoopAliveUntil(Promise.all(pending)).then(finish)
+    : finish()
 }
 
 function __finishWasiDisposal() {
@@ -831,7 +1025,11 @@ function __captureEmnapiAutoDestroyListener() {
 try {
   const __finishAutoDestroyCapture = __captureEmnapiAutoDestroyListener()
   try {
-    __emnapiContext = __emnapiCreateContext({ autoDestroy: false })
+    __emnapiContext = __wrapEmnapiContextDestroyForSettlement(
+      __emnapiCreateContext({ autoDestroy: false }),
+      __prepareWasmEnvCleanup,
+      __isPreparingWasmEnvCleanup,
+    )
     // emnapi 2.x still registers an unconditional once-listener for
     // beforeExit that auto-destroys the context, and suppressDestroy() only
     // neutralizes its callback without removing it. This loader owns cleanup
@@ -859,7 +1057,7 @@ try {
       }
     })(),
     reuseWorker: true,
-    plugins: [__emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
+    plugins: [__captureWasiThreadManager, __emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
     wasi: __wasi,
     onCreateWorker() {
       const worker = __createWasiWorker(__nodePath.join(__dirname, 'wasi-worker.mjs'))
@@ -889,6 +1087,10 @@ try {
         }
 
         worker.unref()
+        // These stubs stay in place for the worker's whole life, disposal
+        // included: `__keepEventLoopAliveUntil` is what holds the process open
+        // while a termination is pending, precisely because a worker's own
+        // references cannot be relied on for it.
       }
       return worker
     },
@@ -911,6 +1113,22 @@ try {
     },
   }))
   __publishWasiDispose(__napiModule.exports)
+  // The CommonJS tail below aliases `__napiModule.exports`; a named module
+  // export does not travel with it, so carry the marker on the binding itself
+  // too. Three things pin the stamp to exactly this spot:
+  //   - inside this `try`, because the guard throws on a
+  //     `#[napi(module_exports)]` hook that claimed the name, and only the
+  //     catch below tears the environment — context, workers, exit listener —
+  //     back down;
+  //   - after the async runtime host install, which hands this same object to
+  //     addon-provided registration functions that may put anything on it;
+  //   - assigning onto the loader's own `module.exports`, which is still the
+  //     original object here, so an addon accessor with a refusing setter is
+  //     never written through. `cjs-module-lexer` — Node's CJS -> ESM named
+  //     export detection — reads the static `module.exports.<name> =` either
+  //     way, and the later `module.exports = __napiModule.exports` does not
+  //     undo that.
+  module.exports.__napiBindingTarget = __napiStampBindingTarget(__napiModule.exports, __napiBindingTarget)
   __registerWasiExitListener()
 } catch (error) {
   const rollback = {

napi/minify/minify.wasi.d.cts

@@ -1,6 +1,9 @@
 /* auto-generated by NAPI-RS */
 /* eslint-disable */
 
+/** The WASI flavor this loader instantiates. */
+export declare const __napiBindingTarget: 'wasm32-wasi'
+
 export interface CodegenOptions {
   /**
    * Remove whitespace.

napi/parser/src-js/bindings.js

@@ -7,6 +7,10 @@ const require = createRequire(import.meta.url)
 
 const { readFileSync } = require('fs')
 let nativeBinding = null
+// Which artifact actually loaded. The WASI fallback chain overwrites it with
+// the flavor it resolved; the late native retry below leaves it alone because
+// it only runs while no WASI candidate has been loaded.
+let __napiLoadedBindingTarget = 'native'
 const loadErrors = []
 
 const isMusl = () => {
@@ -65,7 +69,16 @@ const isMuslFromChildProcess = () => {
 function requireNative() {
   if (process.env.NAPI_RS_NATIVE_LIBRARY_PATH) {
     try {
-      return require(process.env.NAPI_RS_NATIVE_LIBRARY_PATH)
+      const overrideBinding = require(process.env.NAPI_RS_NATIVE_LIBRARY_PATH)
+      // The override may be a generated WASI loader, which already reports its
+      // own flavor. Adopt it: `module.exports` aliases this object, so claiming
+      // 'native' would both misreport the artifact and overwrite the loader's
+      // marker through the alias.
+      __napiLoadedBindingTarget =
+        overrideBinding && typeof overrideBinding.__napiBindingTarget === 'string'
+          ? overrideBinding.__napiBindingTarget
+          : 'native'
+      return overrideBinding
     } catch (err) {
       loadErrors.push(err)
     }
@@ -630,6 +643,7 @@ if (!nativeBinding || forceWasi) {
       if (!candidateFailed) {
         wasiBinding = require('./parser.wasi.cjs')
         nativeBinding = wasiBinding
+        __napiLoadedBindingTarget = 'wasm32-wasi'
         wasiBindingLoaded = true
       }
     } catch (err) {
@@ -656,6 +670,7 @@ if (!nativeBinding || forceWasi) {
         }
         wasiBinding = require('@oxc-parser/binding-wasm32-wasi')
         nativeBinding = wasiBinding
+        __napiLoadedBindingTarget = 'wasm32-wasi'
         wasiBindingLoaded = true
       }
     } catch (err) {
@@ -719,5 +734,6 @@ export { ImportNameKind }
 export { parse }
 export { parseSync }
 export { rawTransferSupported }
+export const __napiBindingTarget = __napiLoadedBindingTarget
 const { getBufferOffset, parseRaw, parseRawSync } = nativeBinding
 export { getBufferOffset, parseRaw, parseRawSync }

napi/parser/src-js/index.d.ts

@@ -15,6 +15,14 @@ export class Visitor {
   visit(program: Program): void;
 }
 
+/**
+ * Which binding artifact the generated loader actually loaded: `'native'` for
+ * a native addon, otherwise the `platformArchABI` of the WASI flavor. Every
+ * flavor napi-rs can build is listed, because `NAPI_RS_NATIVE_LIBRARY_PATH`
+ * can point the loader at a WASI artifact this package does not build itself.
+ */
+export declare const __napiBindingTarget: 'native' | 'wasm32-wasi' | 'wasm32-wasip1'
+
 export interface Comment {
   type: 'Line' | 'Block'
   value: string

napi/parser/src-js/parser.wasi-browser.js

@@ -8,6 +8,55 @@ import {
 import { createContext as __emnapiCreateContext } from '@emnapi/runtime'
 
 
+export const __napiBindingTarget = 'wasm32-wasi'
+function __napiStampBindingTarget(exportsObject, target) {
+  if (
+    Object.prototype.hasOwnProperty.call(exportsObject, '__napiBindingTarget')
+  ) {
+    if (exportsObject.__napiBindingTarget === target) {
+      // Already ours: the root entry aliases the object it loaded, so a WASI
+      // fallback candidate — or a `NAPI_RS_NATIVE_LIBRARY_PATH` override that
+      // is a generated loader — arrives already stamped with this same value.
+      return target
+    }
+    const error = new Error(
+      '`__napiBindingTarget` is reserved by the generated binding loader, but the loaded binding already exports it. Rename the export, e.g. #[napi(js_name = "...")].',
+    )
+    error.code = 'ERR_NAPI_BINDING_TARGET_CONFLICT'
+    throw error
+  }
+  if (!Object.isExtensible(exportsObject)) {
+    // A `#[napi(module_exports)]` hook may seal or freeze this object
+    // (`Object::seal` / `Object::freeze`). Reporting the artifact is metadata,
+    // never a reason to fail an otherwise successful load, so the stamp is
+    // skipped. What a consumer still sees then follows the entry point: the
+    // browser and deferred loaders declare `__napiBindingTarget` at module
+    // level and go on reporting it, while the CommonJS entries hand back this
+    // very object as `module.exports`, so there the value is absent.
+    return target
+  }
+  try {
+    // [[Define]], not [[Set]]: an ordinary assignment walks the prototype
+    // chain, so an inherited accessor could swallow the value or throw and
+    // fail an otherwise successful load. The descriptor is what a successful
+    // assignment would have produced.
+    Object.defineProperty(exportsObject, '__napiBindingTarget', {
+      configurable: true,
+      enumerable: true,
+      value: target,
+      writable: true,
+    })
+  } catch {
+    // Same rule as the non-extensible skip above: reporting the artifact is
+    // metadata, never a reason to fail an otherwise successful load. An exotic
+    // object (a Proxy whose defineProperty trap refuses) is skipped, not
+    // thrown over.
+  }
+  // The CommonJS loaders assign this return value so `cjs-module-lexer` — and
+  // therefore Node's CJS -> ESM named export detection — can see
+  // `__napiBindingTarget` statically.
+  return target
+}
 
 const __wasi = new __WASI({
   version: 'preview1',
@@ -42,10 +91,40 @@ let __emnapiContext
 
 const __wasiDisposeSymbol = Symbol.for('napi.rs.wasi.dispose')
 const __wasiWorkers = new Set()
+// The thread manager has to be reachable *before* anything that can throw
+// during load or registration. Initialization can fail after the pool has
+// already spawned workers, and the rollback still has to mark their
+// terminations as expected — but `__napiModule` is assigned only when
+// instantiation RETURNS, so on exactly that path it is still undefined. A
+// plugin factory runs while the emnapi module is being created, before the
+// wasm is loaded and before any registration function runs, and its context
+// carries the very same manager instance.
+let __wasiThreadManager
+
+function __captureWasiThreadManager(context) {
+  if (context && context.PThread) {
+    __wasiThreadManager = context.PThread
+  }
+  return {}
+}
+
+function __getWasiThreadManager() {
+  const manager =
+    __wasiThreadManager !== undefined
+      ? __wasiThreadManager
+      : __napiModule
+        ? __napiModule.PThread
+        : undefined
+  if (manager && typeof manager.terminateWorker === 'function') {
+    return manager
+  }
+  return undefined
+}
 let __napiInstance
 let __emnapiContextDestroyed = false
 let __emnapiContextDestroyPromise
 let __emnapiWasmEnvCleanupPrepared = false
+let __emnapiWasmEnvCleanupPreparing = false
 let __emnapiWasmEnvCleanupRan = false
 let __emnapiWasmEnvCleanupDrained = false
 let __emnapiWasmEnvCleanupDrainPromise
@@ -119,13 +198,58 @@ function __attachCleanupErrors(error, cleanupErrors) {
   return aggregate
 }
 
+function __wrapEmnapiContextDestroyForSettlement(
+  context,
+  prepareEnvCleanup,
+  isPreparingEnvCleanup,
+) {
+  let destroy
+  try {
+    destroy = context.destroy
+  } catch {
+    return context
+  }
+  if (typeof destroy !== 'function') {
+    return context
+  }
+  try {
+    Object.defineProperty(context, 'destroy', {
+      configurable: true,
+      enumerable: false,
+      writable: true,
+      value: function () {
+        // Reentered from a promise hook that fired inside the barrier: the
+        // frame running it destroys as soon as it returns.
+        if (isPreparingEnvCleanup?.()) {
+          return
+        }
+        prepareEnvCleanup?.()
+        return Reflect.apply(destroy, this, arguments)
+      },
+    })
+  } catch {}
+  return context
+}
+
+function __isPreparingWasmEnvCleanup() {
+  return __emnapiWasmEnvCleanupPreparing
+}
+
 function __prepareWasmEnvCleanup() {
-  if (__emnapiWasmEnvCleanupPrepared) {
+  if (__emnapiWasmEnvCleanupPrepared || __emnapiWasmEnvCleanupPreparing) {
     return
   }
   const prepare = __napiInstance?.exports?.napi_prepare_wasm_env_cleanup
   if (typeof prepare === 'function') {
-    prepare()
+    // The addon settles the promises it cancels synchronously, under a
+    // non-reentrant lifecycle mutex: anything a promise hook calls from in
+    // here must not reach this export again.
+    __emnapiWasmEnvCleanupPreparing = true
+    try {
+      prepare()
+    } finally {
+      __emnapiWasmEnvCleanupPreparing = false
+    }
     __emnapiWasmEnvCleanupRan = true
   }
   __emnapiWasmEnvCleanupPrepared = true
@@ -318,13 +442,80 @@ function __destroyEmnapiContext() {
   return destroyPromise
 }
 
+/**
+ * Holds the event loop open until `work` settles.
+ *
+ * Nothing else can: the pool workers are deliberately unreferenced so an idle
+ * binding cannot keep a process alive, and referencing them again for the
+ * termination does not hold either — emnapi unreferences a worker the moment it
+ * reports `async-thread-ready`, which for a worker that was still starting
+ * lands *after* the termination began. Without a handle of its own, an
+ * `await dispose()` with nothing else pending exits the process with its
+ * promise unsettled, and everything after the `await` is skipped.
+ *
+ * The timer is cleared as soon as the work settles, so this never outlives the
+ * disposal that asked for it.
+ */
+function __keepEventLoopAliveUntil(work) {
+  const setTimer = globalThis.setInterval
+  const clearTimer = globalThis.clearInterval
+  if (typeof setTimer !== 'function' || typeof clearTimer !== 'function') {
+    return work
+  }
+  let timer
+  try {
+    timer = setTimer(function () {}, 50)
+  } catch {
+    return work
+  }
+  const release = function () {
+    try {
+      clearTimer(timer)
+    } catch {}
+  }
+  return work.then(
+    (value) => {
+      release()
+      return value
+    },
+    (error) => {
+      release()
+      throw error
+    },
+  )
+}
+
+/**
+ * `@emnapi/wasi-threads` counts a worker exit as expected only when its own
+ * thread manager performed the termination. A bare `worker.terminate()` reaches
+ * the manager's `exit` listener instead, which reports
+ * `worker (tid = N) sent an error! ... stopped with exit code 1` and rethrows
+ * inside the emit — aborting the `once('exit')` that backs the terminate
+ * promise, so disposal never settles and the process dies with an uncaught
+ * exception. Mark the termination through the manager first.
+ *
+ * The manager comes from `__getWasiThreadManager`, not from `__napiModule`:
+ * the initialization rollback runs on the one path where instantiation never
+ * returned, so `__napiModule` is still undefined there while the workers it
+ * spawned are already registered and loaded.
+ *
+ * Not `terminateAllThreads()`: that one recreates the pool it just shut down.
+ */
 function __terminateWasiWorkers() {
   const cleanupErrors = []
   const pending = []
+  const threadManager = __getWasiThreadManager()
 
   for (const worker of __wasiWorkers) {
     let result
     try {
+      if (threadManager) {
+        threadManager.terminateWorker(worker)
+        // `terminateWorker` leaves behind a reporter that logs every message
+        // still queued on the port, which Node flushes on exit. Nothing is
+        // listening for those any more.
+        worker.onmessage = undefined
+      }
       result = worker.terminate()
     } catch (error) {
       cleanupErrors.push(error)
@@ -354,7 +545,9 @@ function __terminateWasiWorkers() {
       )
     }
   }
-  return pending.length > 0 ? Promise.all(pending).then(finish) : finish()
+  return pending.length > 0
+    ? __keepEventLoopAliveUntil(Promise.all(pending)).then(finish)
+    : finish()
 }
 
 function __finishWasiDisposal() {
@@ -555,7 +748,11 @@ let __wasiModule
 let __napiModule
 
 try {
-  __emnapiContext = __emnapiCreateContext({ autoDestroy: false })
+  __emnapiContext = __wrapEmnapiContextDestroyForSettlement(
+    __emnapiCreateContext({ autoDestroy: false }),
+    __prepareWasmEnvCleanup,
+    __isPreparingWasmEnvCleanup,
+  )
   __emnapiContext.suppressDestroy()
   
   ;({
@@ -566,7 +763,7 @@ try {
     context: __emnapiContext,
     asyncWorkPoolSize: __asyncWorkPoolSize,
     reuseWorker: false,
-    plugins: [__emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
+    plugins: [__captureWasiThreadManager, __emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
     wasi: __wasi,
     onCreateWorker() {
       const worker = new Worker(new URL('./wasi-worker-browser.mjs', import.meta.url), {
@@ -596,6 +793,12 @@ try {
     },
   }))
   __publishWasiDispose(__napiModule.exports)
+  // The default export hands out this object; a named module export does not
+  // travel with it, so carry the marker on the binding itself too. After the
+  // host install, which hands the same object to addon-provided registration
+  // functions that may put anything on it, and inside this `try`, so a claimed
+  // name fails the load through the rollback below rather than past it.
+  __napiStampBindingTarget(__napiModule.exports, __napiBindingTarget)
 } catch (error) {
   const cleanupErrors = await __rollbackWasiInitialization()
   throw __attachCleanupErrors(error, cleanupErrors)

napi/parser/src-js/parser.wasi.cjs

@@ -2,6 +2,56 @@
 /* eslint-disable */
 /* auto-generated by NAPI-RS */
 
+const __napiBindingTarget = 'wasm32-wasi'
+function __napiStampBindingTarget(exportsObject, target) {
+  if (
+    Object.prototype.hasOwnProperty.call(exportsObject, '__napiBindingTarget')
+  ) {
+    if (exportsObject.__napiBindingTarget === target) {
+      // Already ours: the root entry aliases the object it loaded, so a WASI
+      // fallback candidate — or a `NAPI_RS_NATIVE_LIBRARY_PATH` override that
+      // is a generated loader — arrives already stamped with this same value.
+      return target
+    }
+    const error = new Error(
+      '`__napiBindingTarget` is reserved by the generated binding loader, but the loaded binding already exports it. Rename the export, e.g. #[napi(js_name = "...")].',
+    )
+    error.code = 'ERR_NAPI_BINDING_TARGET_CONFLICT'
+    throw error
+  }
+  if (!Object.isExtensible(exportsObject)) {
+    // A `#[napi(module_exports)]` hook may seal or freeze this object
+    // (`Object::seal` / `Object::freeze`). Reporting the artifact is metadata,
+    // never a reason to fail an otherwise successful load, so the stamp is
+    // skipped. What a consumer still sees then follows the entry point: the
+    // browser and deferred loaders declare `__napiBindingTarget` at module
+    // level and go on reporting it, while the CommonJS entries hand back this
+    // very object as `module.exports`, so there the value is absent.
+    return target
+  }
+  try {
+    // [[Define]], not [[Set]]: an ordinary assignment walks the prototype
+    // chain, so an inherited accessor could swallow the value or throw and
+    // fail an otherwise successful load. The descriptor is what a successful
+    // assignment would have produced.
+    Object.defineProperty(exportsObject, '__napiBindingTarget', {
+      configurable: true,
+      enumerable: true,
+      value: target,
+      writable: true,
+    })
+  } catch {
+    // Same rule as the non-extensible skip above: reporting the artifact is
+    // metadata, never a reason to fail an otherwise successful load. An exotic
+    // object (a Proxy whose defineProperty trap refuses) is skipped, not
+    // thrown over.
+  }
+  // The CommonJS loaders assign this return value so `cjs-module-lexer` — and
+  // therefore Node's CJS -> ESM named export detection — can see
+  // `__napiBindingTarget` statically.
+  return target
+}
+
 const __nodeFs = require('node:fs')
 const __nodePath = require('node:path')
 const { WASI: __nodeWASI } = require('node:wasi')
@@ -149,10 +199,40 @@ let __emnapiContext
 
 const __wasiDisposeSymbol = Symbol.for('napi.rs.wasi.dispose')
 const __wasiWorkers = new Set()
+// The thread manager has to be reachable *before* anything that can throw
+// during load or registration. Initialization can fail after the pool has
+// already spawned workers, and the rollback still has to mark their
+// terminations as expected — but `__napiModule` is assigned only when
+// instantiation RETURNS, so on exactly that path it is still undefined. A
+// plugin factory runs while the emnapi module is being created, before the
+// wasm is loaded and before any registration function runs, and its context
+// carries the very same manager instance.
+let __wasiThreadManager
+
+function __captureWasiThreadManager(context) {
+  if (context && context.PThread) {
+    __wasiThreadManager = context.PThread
+  }
+  return {}
+}
+
+function __getWasiThreadManager() {
+  const manager =
+    __wasiThreadManager !== undefined
+      ? __wasiThreadManager
+      : __napiModule
+        ? __napiModule.PThread
+        : undefined
+  if (manager && typeof manager.terminateWorker === 'function') {
+    return manager
+  }
+  return undefined
+}
 let __napiInstance
 let __emnapiContextDestroyed = false
 let __emnapiContextDestroyPromise
 let __emnapiWasmEnvCleanupPrepared = false
+let __emnapiWasmEnvCleanupPreparing = false
 let __emnapiWasmEnvCleanupRan = false
 let __emnapiWasmEnvCleanupDrained = false
 let __emnapiWasmEnvCleanupDrainPromise
@@ -226,13 +306,58 @@ function __attachCleanupErrors(error, cleanupErrors) {
   return aggregate
 }
 
+function __wrapEmnapiContextDestroyForSettlement(
+  context,
+  prepareEnvCleanup,
+  isPreparingEnvCleanup,
+) {
+  let destroy
+  try {
+    destroy = context.destroy
+  } catch {
+    return context
+  }
+  if (typeof destroy !== 'function') {
+    return context
+  }
+  try {
+    Object.defineProperty(context, 'destroy', {
+      configurable: true,
+      enumerable: false,
+      writable: true,
+      value: function () {
+        // Reentered from a promise hook that fired inside the barrier: the
+        // frame running it destroys as soon as it returns.
+        if (isPreparingEnvCleanup?.()) {
+          return
+        }
+        prepareEnvCleanup?.()
+        return Reflect.apply(destroy, this, arguments)
+      },
+    })
+  } catch {}
+  return context
+}
+
+function __isPreparingWasmEnvCleanup() {
+  return __emnapiWasmEnvCleanupPreparing
+}
+
 function __prepareWasmEnvCleanup() {
-  if (__emnapiWasmEnvCleanupPrepared) {
+  if (__emnapiWasmEnvCleanupPrepared || __emnapiWasmEnvCleanupPreparing) {
     return
   }
   const prepare = __napiInstance?.exports?.napi_prepare_wasm_env_cleanup
   if (typeof prepare === 'function') {
-    prepare()
+    // The addon settles the promises it cancels synchronously, under a
+    // non-reentrant lifecycle mutex: anything a promise hook calls from in
+    // here must not reach this export again.
+    __emnapiWasmEnvCleanupPreparing = true
+    try {
+      prepare()
+    } finally {
+      __emnapiWasmEnvCleanupPreparing = false
+    }
     __emnapiWasmEnvCleanupRan = true
   }
   __emnapiWasmEnvCleanupPrepared = true
@@ -425,13 +550,80 @@ function __destroyEmnapiContext() {
   return destroyPromise
 }
 
+/**
+ * Holds the event loop open until `work` settles.
+ *
+ * Nothing else can: the pool workers are deliberately unreferenced so an idle
+ * binding cannot keep a process alive, and referencing them again for the
+ * termination does not hold either — emnapi unreferences a worker the moment it
+ * reports `async-thread-ready`, which for a worker that was still starting
+ * lands *after* the termination began. Without a handle of its own, an
+ * `await dispose()` with nothing else pending exits the process with its
+ * promise unsettled, and everything after the `await` is skipped.
+ *
+ * The timer is cleared as soon as the work settles, so this never outlives the
+ * disposal that asked for it.
+ */
+function __keepEventLoopAliveUntil(work) {
+  const setTimer = globalThis.setInterval
+  const clearTimer = globalThis.clearInterval
+  if (typeof setTimer !== 'function' || typeof clearTimer !== 'function') {
+    return work
+  }
+  let timer
+  try {
+    timer = setTimer(function () {}, 50)
+  } catch {
+    return work
+  }
+  const release = function () {
+    try {
+      clearTimer(timer)
+    } catch {}
+  }
+  return work.then(
+    (value) => {
+      release()
+      return value
+    },
+    (error) => {
+      release()
+      throw error
+    },
+  )
+}
+
+/**
+ * `@emnapi/wasi-threads` counts a worker exit as expected only when its own
+ * thread manager performed the termination. A bare `worker.terminate()` reaches
+ * the manager's `exit` listener instead, which reports
+ * `worker (tid = N) sent an error! ... stopped with exit code 1` and rethrows
+ * inside the emit — aborting the `once('exit')` that backs the terminate
+ * promise, so disposal never settles and the process dies with an uncaught
+ * exception. Mark the termination through the manager first.
+ *
+ * The manager comes from `__getWasiThreadManager`, not from `__napiModule`:
+ * the initialization rollback runs on the one path where instantiation never
+ * returned, so `__napiModule` is still undefined there while the workers it
+ * spawned are already registered and loaded.
+ *
+ * Not `terminateAllThreads()`: that one recreates the pool it just shut down.
+ */
 function __terminateWasiWorkers() {
   const cleanupErrors = []
   const pending = []
+  const threadManager = __getWasiThreadManager()
 
   for (const worker of __wasiWorkers) {
     let result
     try {
+      if (threadManager) {
+        threadManager.terminateWorker(worker)
+        // `terminateWorker` leaves behind a reporter that logs every message
+        // still queued on the port, which Node flushes on exit. Nothing is
+        // listening for those any more.
+        worker.onmessage = undefined
+      }
       result = worker.terminate()
     } catch (error) {
       cleanupErrors.push(error)
@@ -461,7 +653,9 @@ function __terminateWasiWorkers() {
       )
     }
   }
-  return pending.length > 0 ? Promise.all(pending).then(finish) : finish()
+  return pending.length > 0
+    ? __keepEventLoopAliveUntil(Promise.all(pending)).then(finish)
+    : finish()
 }
 
 function __finishWasiDisposal() {
@@ -831,7 +1025,11 @@ function __captureEmnapiAutoDestroyListener() {
 try {
   const __finishAutoDestroyCapture = __captureEmnapiAutoDestroyListener()
   try {
-    __emnapiContext = __emnapiCreateContext({ autoDestroy: false })
+    __emnapiContext = __wrapEmnapiContextDestroyForSettlement(
+      __emnapiCreateContext({ autoDestroy: false }),
+      __prepareWasmEnvCleanup,
+      __isPreparingWasmEnvCleanup,
+    )
     // emnapi 2.x still registers an unconditional once-listener for
     // beforeExit that auto-destroys the context, and suppressDestroy() only
     // neutralizes its callback without removing it. This loader owns cleanup
@@ -859,7 +1057,7 @@ try {
       }
     })(),
     reuseWorker: true,
-    plugins: [__emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
+    plugins: [__captureWasiThreadManager, __emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
     wasi: __wasi,
     onCreateWorker() {
       const worker = __createWasiWorker(__nodePath.join(__dirname, 'wasi-worker.mjs'))
@@ -889,6 +1087,10 @@ try {
         }
 
         worker.unref()
+        // These stubs stay in place for the worker's whole life, disposal
+        // included: `__keepEventLoopAliveUntil` is what holds the process open
+        // while a termination is pending, precisely because a worker's own
+        // references cannot be relied on for it.
       }
       return worker
     },
@@ -911,6 +1113,22 @@ try {
     },
   }))
   __publishWasiDispose(__napiModule.exports)
+  // The CommonJS tail below aliases `__napiModule.exports`; a named module
+  // export does not travel with it, so carry the marker on the binding itself
+  // too. Three things pin the stamp to exactly this spot:
+  //   - inside this `try`, because the guard throws on a
+  //     `#[napi(module_exports)]` hook that claimed the name, and only the
+  //     catch below tears the environment — context, workers, exit listener —
+  //     back down;
+  //   - after the async runtime host install, which hands this same object to
+  //     addon-provided registration functions that may put anything on it;
+  //   - assigning onto the loader's own `module.exports`, which is still the
+  //     original object here, so an addon accessor with a refusing setter is
+  //     never written through. `cjs-module-lexer` — Node's CJS -> ESM named
+  //     export detection — reads the static `module.exports.<name> =` either
+  //     way, and the later `module.exports = __napiModule.exports` does not
+  //     undo that.
+  module.exports.__napiBindingTarget = __napiStampBindingTarget(__napiModule.exports, __napiBindingTarget)
   __registerWasiExitListener()
 } catch (error) {
   const rollback = {

napi/parser/src-js/parser.wasi.d.cts

@@ -1,3 +1,7 @@
+
+/** The WASI flavor this loader instantiates. */
+export declare const __napiBindingTarget: 'wasm32-wasi'
+
 export interface Comment {
   type: 'Line' | 'Block'
   value: string

napi/playground/index.js

@@ -7,6 +7,10 @@ const require = createRequire(import.meta.url)
 
 const { readFileSync } = require('fs')
 let nativeBinding = null
+// Which artifact actually loaded. The WASI fallback chain overwrites it with
+// the flavor it resolved; the late native retry below leaves it alone because
+// it only runs while no WASI candidate has been loaded.
+let __napiLoadedBindingTarget = 'native'
 const loadErrors = []
 
 const isMusl = () => {
@@ -65,7 +69,16 @@ const isMuslFromChildProcess = () => {
 function requireNative() {
   if (process.env.NAPI_RS_NATIVE_LIBRARY_PATH) {
     try {
-      return require(process.env.NAPI_RS_NATIVE_LIBRARY_PATH)
+      const overrideBinding = require(process.env.NAPI_RS_NATIVE_LIBRARY_PATH)
+      // The override may be a generated WASI loader, which already reports its
+      // own flavor. Adopt it: `module.exports` aliases this object, so claiming
+      // 'native' would both misreport the artifact and overwrite the loader's
+      // marker through the alias.
+      __napiLoadedBindingTarget =
+        overrideBinding && typeof overrideBinding.__napiBindingTarget === 'string'
+          ? overrideBinding.__napiBindingTarget
+          : 'native'
+      return overrideBinding
     } catch (err) {
       loadErrors.push(err)
     }
@@ -630,6 +643,7 @@ if (!nativeBinding || forceWasi) {
       if (!candidateFailed) {
         wasiBinding = require('./playground.wasi.cjs')
         nativeBinding = wasiBinding
+        __napiLoadedBindingTarget = 'wasm32-wasi'
         wasiBindingLoaded = true
       }
     } catch (err) {
@@ -656,6 +670,7 @@ if (!nativeBinding || forceWasi) {
         }
         wasiBinding = require('@oxc-playground/binding-wasm32-wasi')
         nativeBinding = wasiBinding
+        __napiLoadedBindingTarget = 'wasm32-wasi'
         wasiBindingLoaded = true
       }
     } catch (err) {
@@ -704,3 +719,4 @@ if (!nativeBinding) {
 const { Severity, Oxc } = nativeBinding
 export { Severity }
 export { Oxc }
+export const __napiBindingTarget = __napiLoadedBindingTarget

napi/playground/playground.wasi-browser.js

@@ -8,6 +8,55 @@ import {
 import { createContext as __emnapiCreateContext } from '@emnapi/runtime'
 
 
+export const __napiBindingTarget = 'wasm32-wasi'
+function __napiStampBindingTarget(exportsObject, target) {
+  if (
+    Object.prototype.hasOwnProperty.call(exportsObject, '__napiBindingTarget')
+  ) {
+    if (exportsObject.__napiBindingTarget === target) {
+      // Already ours: the root entry aliases the object it loaded, so a WASI
+      // fallback candidate — or a `NAPI_RS_NATIVE_LIBRARY_PATH` override that
+      // is a generated loader — arrives already stamped with this same value.
+      return target
+    }
+    const error = new Error(
+      '`__napiBindingTarget` is reserved by the generated binding loader, but the loaded binding already exports it. Rename the export, e.g. #[napi(js_name = "...")].',
+    )
+    error.code = 'ERR_NAPI_BINDING_TARGET_CONFLICT'
+    throw error
+  }
+  if (!Object.isExtensible(exportsObject)) {
+    // A `#[napi(module_exports)]` hook may seal or freeze this object
+    // (`Object::seal` / `Object::freeze`). Reporting the artifact is metadata,
+    // never a reason to fail an otherwise successful load, so the stamp is
+    // skipped. What a consumer still sees then follows the entry point: the
+    // browser and deferred loaders declare `__napiBindingTarget` at module
+    // level and go on reporting it, while the CommonJS entries hand back this
+    // very object as `module.exports`, so there the value is absent.
+    return target
+  }
+  try {
+    // [[Define]], not [[Set]]: an ordinary assignment walks the prototype
+    // chain, so an inherited accessor could swallow the value or throw and
+    // fail an otherwise successful load. The descriptor is what a successful
+    // assignment would have produced.
+    Object.defineProperty(exportsObject, '__napiBindingTarget', {
+      configurable: true,
+      enumerable: true,
+      value: target,
+      writable: true,
+    })
+  } catch {
+    // Same rule as the non-extensible skip above: reporting the artifact is
+    // metadata, never a reason to fail an otherwise successful load. An exotic
+    // object (a Proxy whose defineProperty trap refuses) is skipped, not
+    // thrown over.
+  }
+  // The CommonJS loaders assign this return value so `cjs-module-lexer` — and
+  // therefore Node's CJS -> ESM named export detection — can see
+  // `__napiBindingTarget` statically.
+  return target
+}
 
 const __wasi = new __WASI({
   version: 'preview1',
@@ -42,10 +91,40 @@ let __emnapiContext
 
 const __wasiDisposeSymbol = Symbol.for('napi.rs.wasi.dispose')
 const __wasiWorkers = new Set()
+// The thread manager has to be reachable *before* anything that can throw
+// during load or registration. Initialization can fail after the pool has
+// already spawned workers, and the rollback still has to mark their
+// terminations as expected — but `__napiModule` is assigned only when
+// instantiation RETURNS, so on exactly that path it is still undefined. A
+// plugin factory runs while the emnapi module is being created, before the
+// wasm is loaded and before any registration function runs, and its context
+// carries the very same manager instance.
+let __wasiThreadManager
+
+function __captureWasiThreadManager(context) {
+  if (context && context.PThread) {
+    __wasiThreadManager = context.PThread
+  }
+  return {}
+}
+
+function __getWasiThreadManager() {
+  const manager =
+    __wasiThreadManager !== undefined
+      ? __wasiThreadManager
+      : __napiModule
+        ? __napiModule.PThread
+        : undefined
+  if (manager && typeof manager.terminateWorker === 'function') {
+    return manager
+  }
+  return undefined
+}
 let __napiInstance
 let __emnapiContextDestroyed = false
 let __emnapiContextDestroyPromise
 let __emnapiWasmEnvCleanupPrepared = false
+let __emnapiWasmEnvCleanupPreparing = false
 let __emnapiWasmEnvCleanupRan = false
 let __emnapiWasmEnvCleanupDrained = false
 let __emnapiWasmEnvCleanupDrainPromise
@@ -119,13 +198,58 @@ function __attachCleanupErrors(error, cleanupErrors) {
   return aggregate
 }
 
+function __wrapEmnapiContextDestroyForSettlement(
+  context,
+  prepareEnvCleanup,
+  isPreparingEnvCleanup,
+) {
+  let destroy
+  try {
+    destroy = context.destroy
+  } catch {
+    return context
+  }
+  if (typeof destroy !== 'function') {
+    return context
+  }
+  try {
+    Object.defineProperty(context, 'destroy', {
+      configurable: true,
+      enumerable: false,
+      writable: true,
+      value: function () {
+        // Reentered from a promise hook that fired inside the barrier: the
+        // frame running it destroys as soon as it returns.
+        if (isPreparingEnvCleanup?.()) {
+          return
+        }
+        prepareEnvCleanup?.()
+        return Reflect.apply(destroy, this, arguments)
+      },
+    })
+  } catch {}
+  return context
+}
+
+function __isPreparingWasmEnvCleanup() {
+  return __emnapiWasmEnvCleanupPreparing
+}
+
 function __prepareWasmEnvCleanup() {
-  if (__emnapiWasmEnvCleanupPrepared) {
+  if (__emnapiWasmEnvCleanupPrepared || __emnapiWasmEnvCleanupPreparing) {
     return
   }
   const prepare = __napiInstance?.exports?.napi_prepare_wasm_env_cleanup
   if (typeof prepare === 'function') {
-    prepare()
+    // The addon settles the promises it cancels synchronously, under a
+    // non-reentrant lifecycle mutex: anything a promise hook calls from in
+    // here must not reach this export again.
+    __emnapiWasmEnvCleanupPreparing = true
+    try {
+      prepare()
+    } finally {
+      __emnapiWasmEnvCleanupPreparing = false
+    }
     __emnapiWasmEnvCleanupRan = true
   }
   __emnapiWasmEnvCleanupPrepared = true
@@ -318,13 +442,80 @@ function __destroyEmnapiContext() {
   return destroyPromise
 }
 
+/**
+ * Holds the event loop open until `work` settles.
+ *
+ * Nothing else can: the pool workers are deliberately unreferenced so an idle
+ * binding cannot keep a process alive, and referencing them again for the
+ * termination does not hold either — emnapi unreferences a worker the moment it
+ * reports `async-thread-ready`, which for a worker that was still starting
+ * lands *after* the termination began. Without a handle of its own, an
+ * `await dispose()` with nothing else pending exits the process with its
+ * promise unsettled, and everything after the `await` is skipped.
+ *
+ * The timer is cleared as soon as the work settles, so this never outlives the
+ * disposal that asked for it.
+ */
+function __keepEventLoopAliveUntil(work) {
+  const setTimer = globalThis.setInterval
+  const clearTimer = globalThis.clearInterval
+  if (typeof setTimer !== 'function' || typeof clearTimer !== 'function') {
+    return work
+  }
+  let timer
+  try {
+    timer = setTimer(function () {}, 50)
+  } catch {
+    return work
+  }
+  const release = function () {
+    try {
+      clearTimer(timer)
+    } catch {}
+  }
+  return work.then(
+    (value) => {
+      release()
+      return value
+    },
+    (error) => {
+      release()
+      throw error
+    },
+  )
+}
+
+/**
+ * `@emnapi/wasi-threads` counts a worker exit as expected only when its own
+ * thread manager performed the termination. A bare `worker.terminate()` reaches
+ * the manager's `exit` listener instead, which reports
+ * `worker (tid = N) sent an error! ... stopped with exit code 1` and rethrows
+ * inside the emit — aborting the `once('exit')` that backs the terminate
+ * promise, so disposal never settles and the process dies with an uncaught
+ * exception. Mark the termination through the manager first.
+ *
+ * The manager comes from `__getWasiThreadManager`, not from `__napiModule`:
+ * the initialization rollback runs on the one path where instantiation never
+ * returned, so `__napiModule` is still undefined there while the workers it
+ * spawned are already registered and loaded.
+ *
+ * Not `terminateAllThreads()`: that one recreates the pool it just shut down.
+ */
 function __terminateWasiWorkers() {
   const cleanupErrors = []
   const pending = []
+  const threadManager = __getWasiThreadManager()
 
   for (const worker of __wasiWorkers) {
     let result
     try {
+      if (threadManager) {
+        threadManager.terminateWorker(worker)
+        // `terminateWorker` leaves behind a reporter that logs every message
+        // still queued on the port, which Node flushes on exit. Nothing is
+        // listening for those any more.
+        worker.onmessage = undefined
+      }
       result = worker.terminate()
     } catch (error) {
       cleanupErrors.push(error)
@@ -354,7 +545,9 @@ function __terminateWasiWorkers() {
       )
     }
   }
-  return pending.length > 0 ? Promise.all(pending).then(finish) : finish()
+  return pending.length > 0
+    ? __keepEventLoopAliveUntil(Promise.all(pending)).then(finish)
+    : finish()
 }
 
 function __finishWasiDisposal() {
@@ -555,7 +748,11 @@ let __wasiModule
 let __napiModule
 
 try {
-  __emnapiContext = __emnapiCreateContext({ autoDestroy: false })
+  __emnapiContext = __wrapEmnapiContextDestroyForSettlement(
+    __emnapiCreateContext({ autoDestroy: false }),
+    __prepareWasmEnvCleanup,
+    __isPreparingWasmEnvCleanup,
+  )
   __emnapiContext.suppressDestroy()
   
   ;({
@@ -566,7 +763,7 @@ try {
     context: __emnapiContext,
     asyncWorkPoolSize: __asyncWorkPoolSize,
     reuseWorker: false,
-    plugins: [__emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
+    plugins: [__captureWasiThreadManager, __emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
     wasi: __wasi,
     onCreateWorker() {
       const worker = new Worker(new URL('./wasi-worker-browser.mjs', import.meta.url), {
@@ -596,6 +793,12 @@ try {
     },
   }))
   __publishWasiDispose(__napiModule.exports)
+  // The default export hands out this object; a named module export does not
+  // travel with it, so carry the marker on the binding itself too. After the
+  // host install, which hands the same object to addon-provided registration
+  // functions that may put anything on it, and inside this `try`, so a claimed
+  // name fails the load through the rollback below rather than past it.
+  __napiStampBindingTarget(__napiModule.exports, __napiBindingTarget)
 } catch (error) {
   const cleanupErrors = await __rollbackWasiInitialization()
   throw __attachCleanupErrors(error, cleanupErrors)

napi/playground/playground.wasi.cjs

@@ -2,6 +2,56 @@
 /* eslint-disable */
 /* auto-generated by NAPI-RS */
 
+const __napiBindingTarget = 'wasm32-wasi'
+function __napiStampBindingTarget(exportsObject, target) {
+  if (
+    Object.prototype.hasOwnProperty.call(exportsObject, '__napiBindingTarget')
+  ) {
+    if (exportsObject.__napiBindingTarget === target) {
+      // Already ours: the root entry aliases the object it loaded, so a WASI
+      // fallback candidate — or a `NAPI_RS_NATIVE_LIBRARY_PATH` override that
+      // is a generated loader — arrives already stamped with this same value.
+      return target
+    }
+    const error = new Error(
+      '`__napiBindingTarget` is reserved by the generated binding loader, but the loaded binding already exports it. Rename the export, e.g. #[napi(js_name = "...")].',
+    )
+    error.code = 'ERR_NAPI_BINDING_TARGET_CONFLICT'
+    throw error
+  }
+  if (!Object.isExtensible(exportsObject)) {
+    // A `#[napi(module_exports)]` hook may seal or freeze this object
+    // (`Object::seal` / `Object::freeze`). Reporting the artifact is metadata,
+    // never a reason to fail an otherwise successful load, so the stamp is
+    // skipped. What a consumer still sees then follows the entry point: the
+    // browser and deferred loaders declare `__napiBindingTarget` at module
+    // level and go on reporting it, while the CommonJS entries hand back this
+    // very object as `module.exports`, so there the value is absent.
+    return target
+  }
+  try {
+    // [[Define]], not [[Set]]: an ordinary assignment walks the prototype
+    // chain, so an inherited accessor could swallow the value or throw and
+    // fail an otherwise successful load. The descriptor is what a successful
+    // assignment would have produced.
+    Object.defineProperty(exportsObject, '__napiBindingTarget', {
+      configurable: true,
+      enumerable: true,
+      value: target,
+      writable: true,
+    })
+  } catch {
+    // Same rule as the non-extensible skip above: reporting the artifact is
+    // metadata, never a reason to fail an otherwise successful load. An exotic
+    // object (a Proxy whose defineProperty trap refuses) is skipped, not
+    // thrown over.
+  }
+  // The CommonJS loaders assign this return value so `cjs-module-lexer` — and
+  // therefore Node's CJS -> ESM named export detection — can see
+  // `__napiBindingTarget` statically.
+  return target
+}
+
 const __nodeFs = require('node:fs')
 const __nodePath = require('node:path')
 const { WASI: __nodeWASI } = require('node:wasi')
@@ -149,10 +199,40 @@ let __emnapiContext
 
 const __wasiDisposeSymbol = Symbol.for('napi.rs.wasi.dispose')
 const __wasiWorkers = new Set()
+// The thread manager has to be reachable *before* anything that can throw
+// during load or registration. Initialization can fail after the pool has
+// already spawned workers, and the rollback still has to mark their
+// terminations as expected — but `__napiModule` is assigned only when
+// instantiation RETURNS, so on exactly that path it is still undefined. A
+// plugin factory runs while the emnapi module is being created, before the
+// wasm is loaded and before any registration function runs, and its context
+// carries the very same manager instance.
+let __wasiThreadManager
+
+function __captureWasiThreadManager(context) {
+  if (context && context.PThread) {
+    __wasiThreadManager = context.PThread
+  }
+  return {}
+}
+
+function __getWasiThreadManager() {
+  const manager =
+    __wasiThreadManager !== undefined
+      ? __wasiThreadManager
+      : __napiModule
+        ? __napiModule.PThread
+        : undefined
+  if (manager && typeof manager.terminateWorker === 'function') {
+    return manager
+  }
+  return undefined
+}
 let __napiInstance
 let __emnapiContextDestroyed = false
 let __emnapiContextDestroyPromise
 let __emnapiWasmEnvCleanupPrepared = false
+let __emnapiWasmEnvCleanupPreparing = false
 let __emnapiWasmEnvCleanupRan = false
 let __emnapiWasmEnvCleanupDrained = false
 let __emnapiWasmEnvCleanupDrainPromise
@@ -226,13 +306,58 @@ function __attachCleanupErrors(error, cleanupErrors) {
   return aggregate
 }
 
+function __wrapEmnapiContextDestroyForSettlement(
+  context,
+  prepareEnvCleanup,
+  isPreparingEnvCleanup,
+) {
+  let destroy
+  try {
+    destroy = context.destroy
+  } catch {
+    return context
+  }
+  if (typeof destroy !== 'function') {
+    return context
+  }
+  try {
+    Object.defineProperty(context, 'destroy', {
+      configurable: true,
+      enumerable: false,
+      writable: true,
+      value: function () {
+        // Reentered from a promise hook that fired inside the barrier: the
+        // frame running it destroys as soon as it returns.
+        if (isPreparingEnvCleanup?.()) {
+          return
+        }
+        prepareEnvCleanup?.()
+        return Reflect.apply(destroy, this, arguments)
+      },
+    })
+  } catch {}
+  return context
+}
+
+function __isPreparingWasmEnvCleanup() {
+  return __emnapiWasmEnvCleanupPreparing
+}
+
 function __prepareWasmEnvCleanup() {
-  if (__emnapiWasmEnvCleanupPrepared) {
+  if (__emnapiWasmEnvCleanupPrepared || __emnapiWasmEnvCleanupPreparing) {
     return
   }
   const prepare = __napiInstance?.exports?.napi_prepare_wasm_env_cleanup
   if (typeof prepare === 'function') {
-    prepare()
+    // The addon settles the promises it cancels synchronously, under a
+    // non-reentrant lifecycle mutex: anything a promise hook calls from in
+    // here must not reach this export again.
+    __emnapiWasmEnvCleanupPreparing = true
+    try {
+      prepare()
+    } finally {
+      __emnapiWasmEnvCleanupPreparing = false
+    }
     __emnapiWasmEnvCleanupRan = true
   }
   __emnapiWasmEnvCleanupPrepared = true
@@ -425,13 +550,80 @@ function __destroyEmnapiContext() {
   return destroyPromise
 }
 
+/**
+ * Holds the event loop open until `work` settles.
+ *
+ * Nothing else can: the pool workers are deliberately unreferenced so an idle
+ * binding cannot keep a process alive, and referencing them again for the
+ * termination does not hold either — emnapi unreferences a worker the moment it
+ * reports `async-thread-ready`, which for a worker that was still starting
+ * lands *after* the termination began. Without a handle of its own, an
+ * `await dispose()` with nothing else pending exits the process with its
+ * promise unsettled, and everything after the `await` is skipped.
+ *
+ * The timer is cleared as soon as the work settles, so this never outlives the
+ * disposal that asked for it.
+ */
+function __keepEventLoopAliveUntil(work) {
+  const setTimer = globalThis.setInterval
+  const clearTimer = globalThis.clearInterval
+  if (typeof setTimer !== 'function' || typeof clearTimer !== 'function') {
+    return work
+  }
+  let timer
+  try {
+    timer = setTimer(function () {}, 50)
+  } catch {
+    return work
+  }
+  const release = function () {
+    try {
+      clearTimer(timer)
+    } catch {}
+  }
+  return work.then(
+    (value) => {
+      release()
+      return value
+    },
+    (error) => {
+      release()
+      throw error
+    },
+  )
+}
+
+/**
+ * `@emnapi/wasi-threads` counts a worker exit as expected only when its own
+ * thread manager performed the termination. A bare `worker.terminate()` reaches
+ * the manager's `exit` listener instead, which reports
+ * `worker (tid = N) sent an error! ... stopped with exit code 1` and rethrows
+ * inside the emit — aborting the `once('exit')` that backs the terminate
+ * promise, so disposal never settles and the process dies with an uncaught
+ * exception. Mark the termination through the manager first.
+ *
+ * The manager comes from `__getWasiThreadManager`, not from `__napiModule`:
+ * the initialization rollback runs on the one path where instantiation never
+ * returned, so `__napiModule` is still undefined there while the workers it
+ * spawned are already registered and loaded.
+ *
+ * Not `terminateAllThreads()`: that one recreates the pool it just shut down.
+ */
 function __terminateWasiWorkers() {
   const cleanupErrors = []
   const pending = []
+  const threadManager = __getWasiThreadManager()
 
   for (const worker of __wasiWorkers) {
     let result
     try {
+      if (threadManager) {
+        threadManager.terminateWorker(worker)
+        // `terminateWorker` leaves behind a reporter that logs every message
+        // still queued on the port, which Node flushes on exit. Nothing is
+        // listening for those any more.
+        worker.onmessage = undefined
+      }
       result = worker.terminate()
     } catch (error) {
       cleanupErrors.push(error)
@@ -461,7 +653,9 @@ function __terminateWasiWorkers() {
       )
     }
   }
-  return pending.length > 0 ? Promise.all(pending).then(finish) : finish()
+  return pending.length > 0
+    ? __keepEventLoopAliveUntil(Promise.all(pending)).then(finish)
+    : finish()
 }
 
 function __finishWasiDisposal() {
@@ -831,7 +1025,11 @@ function __captureEmnapiAutoDestroyListener() {
 try {
   const __finishAutoDestroyCapture = __captureEmnapiAutoDestroyListener()
   try {
-    __emnapiContext = __emnapiCreateContext({ autoDestroy: false })
+    __emnapiContext = __wrapEmnapiContextDestroyForSettlement(
+      __emnapiCreateContext({ autoDestroy: false }),
+      __prepareWasmEnvCleanup,
+      __isPreparingWasmEnvCleanup,
+    )
     // emnapi 2.x still registers an unconditional once-listener for
     // beforeExit that auto-destroys the context, and suppressDestroy() only
     // neutralizes its callback without removing it. This loader owns cleanup
@@ -859,7 +1057,7 @@ try {
       }
     })(),
     reuseWorker: true,
-    plugins: [__emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
+    plugins: [__captureWasiThreadManager, __emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
     wasi: __wasi,
     onCreateWorker() {
       const worker = __createWasiWorker(__nodePath.join(__dirname, 'wasi-worker.mjs'))
@@ -889,6 +1087,10 @@ try {
         }
 
         worker.unref()
+        // These stubs stay in place for the worker's whole life, disposal
+        // included: `__keepEventLoopAliveUntil` is what holds the process open
+        // while a termination is pending, precisely because a worker's own
+        // references cannot be relied on for it.
       }
       return worker
     },
@@ -911,6 +1113,22 @@ try {
     },
   }))
   __publishWasiDispose(__napiModule.exports)
+  // The CommonJS tail below aliases `__napiModule.exports`; a named module
+  // export does not travel with it, so carry the marker on the binding itself
+  // too. Three things pin the stamp to exactly this spot:
+  //   - inside this `try`, because the guard throws on a
+  //     `#[napi(module_exports)]` hook that claimed the name, and only the
+  //     catch below tears the environment — context, workers, exit listener —
+  //     back down;
+  //   - after the async runtime host install, which hands this same object to
+  //     addon-provided registration functions that may put anything on it;
+  //   - assigning onto the loader's own `module.exports`, which is still the
+  //     original object here, so an addon accessor with a refusing setter is
+  //     never written through. `cjs-module-lexer` — Node's CJS -> ESM named
+  //     export detection — reads the static `module.exports.<name> =` either
+  //     way, and the later `module.exports = __napiModule.exports` does not
+  //     undo that.
+  module.exports.__napiBindingTarget = __napiStampBindingTarget(__napiModule.exports, __napiBindingTarget)
   __registerWasiExitListener()
 } catch (error) {
   const rollback = {

napi/playground/playground.wasi.d.cts

@@ -1,6 +1,9 @@
 /* auto-generated by NAPI-RS */
 /* eslint-disable */
 
+/** The WASI flavor this loader instantiates. */
+export declare const __napiBindingTarget: 'wasm32-wasi'
+
 export interface Comment {
   type: 'Line' | 'Block'
   value: string

napi/transform-react/index.d.ts

@@ -1,6 +1,14 @@
 /* auto-generated by NAPI-RS */
 /* eslint-disable */
 
+/**
+ * Which binding artifact the generated loader actually loaded: `'native'` for
+ * a native addon, otherwise the `platformArchABI` of the WASI flavor. Every
+ * flavor napi-rs can build is listed, because `NAPI_RS_NATIVE_LIBRARY_PATH`
+ * can point the loader at a WASI artifact this package does not build itself.
+ */
+export declare const __napiBindingTarget: 'native' | 'wasm32-wasi' | 'wasm32-wasip1'
+
 export interface Comment {
   type: 'Line' | 'Block'
   value: string

napi/transform-react/index.js

@@ -7,6 +7,10 @@ const require = createRequire(import.meta.url)
 
 const { readFileSync } = require('fs')
 let nativeBinding = null
+// Which artifact actually loaded. The WASI fallback chain overwrites it with
+// the flavor it resolved; the late native retry below leaves it alone because
+// it only runs while no WASI candidate has been loaded.
+let __napiLoadedBindingTarget = 'native'
 const loadErrors = []
 
 const isMusl = () => {
@@ -65,7 +69,16 @@ const isMuslFromChildProcess = () => {
 function requireNative() {
   if (process.env.NAPI_RS_NATIVE_LIBRARY_PATH) {
     try {
-      return require(process.env.NAPI_RS_NATIVE_LIBRARY_PATH)
+      const overrideBinding = require(process.env.NAPI_RS_NATIVE_LIBRARY_PATH)
+      // The override may be a generated WASI loader, which already reports its
+      // own flavor. Adopt it: `module.exports` aliases this object, so claiming
+      // 'native' would both misreport the artifact and overwrite the loader's
+      // marker through the alias.
+      __napiLoadedBindingTarget =
+        overrideBinding && typeof overrideBinding.__napiBindingTarget === 'string'
+          ? overrideBinding.__napiBindingTarget
+          : 'native'
+      return overrideBinding
     } catch (err) {
       loadErrors.push(err)
     }
@@ -630,6 +643,7 @@ if (!nativeBinding || forceWasi) {
       if (!candidateFailed) {
         wasiBinding = require('./transform-react.wasi.cjs')
         nativeBinding = wasiBinding
+        __napiLoadedBindingTarget = 'wasm32-wasi'
         wasiBindingLoaded = true
       }
     } catch (err) {
@@ -656,6 +670,7 @@ if (!nativeBinding || forceWasi) {
         }
         wasiBinding = require('@oxc-transform-react/binding-wasm32-wasi')
         nativeBinding = wasiBinding
+        __napiLoadedBindingTarget = 'wasm32-wasi'
         wasiBindingLoaded = true
       }
     } catch (err) {
@@ -713,3 +728,4 @@ const { Severity, transform, transformSync } = nativeBinding
 export { Severity }
 export { transform }
 export { transformSync }
+export const __napiBindingTarget = __napiLoadedBindingTarget

napi/transform-react/transform-react.wasi-browser.js

@@ -8,6 +8,55 @@ import {
 import { createContext as __emnapiCreateContext } from '@emnapi/runtime'
 
 
+export const __napiBindingTarget = 'wasm32-wasi'
+function __napiStampBindingTarget(exportsObject, target) {
+  if (
+    Object.prototype.hasOwnProperty.call(exportsObject, '__napiBindingTarget')
+  ) {
+    if (exportsObject.__napiBindingTarget === target) {
+      // Already ours: the root entry aliases the object it loaded, so a WASI
+      // fallback candidate — or a `NAPI_RS_NATIVE_LIBRARY_PATH` override that
+      // is a generated loader — arrives already stamped with this same value.
+      return target
+    }
+    const error = new Error(
+      '`__napiBindingTarget` is reserved by the generated binding loader, but the loaded binding already exports it. Rename the export, e.g. #[napi(js_name = "...")].',
+    )
+    error.code = 'ERR_NAPI_BINDING_TARGET_CONFLICT'
+    throw error
+  }
+  if (!Object.isExtensible(exportsObject)) {
+    // A `#[napi(module_exports)]` hook may seal or freeze this object
+    // (`Object::seal` / `Object::freeze`). Reporting the artifact is metadata,
+    // never a reason to fail an otherwise successful load, so the stamp is
+    // skipped. What a consumer still sees then follows the entry point: the
+    // browser and deferred loaders declare `__napiBindingTarget` at module
+    // level and go on reporting it, while the CommonJS entries hand back this
+    // very object as `module.exports`, so there the value is absent.
+    return target
+  }
+  try {
+    // [[Define]], not [[Set]]: an ordinary assignment walks the prototype
+    // chain, so an inherited accessor could swallow the value or throw and
+    // fail an otherwise successful load. The descriptor is what a successful
+    // assignment would have produced.
+    Object.defineProperty(exportsObject, '__napiBindingTarget', {
+      configurable: true,
+      enumerable: true,
+      value: target,
+      writable: true,
+    })
+  } catch {
+    // Same rule as the non-extensible skip above: reporting the artifact is
+    // metadata, never a reason to fail an otherwise successful load. An exotic
+    // object (a Proxy whose defineProperty trap refuses) is skipped, not
+    // thrown over.
+  }
+  // The CommonJS loaders assign this return value so `cjs-module-lexer` — and
+  // therefore Node's CJS -> ESM named export detection — can see
+  // `__napiBindingTarget` statically.
+  return target
+}
 
 const __wasi = new __WASI({
   version: 'preview1',
@@ -42,10 +91,40 @@ let __emnapiContext
 
 const __wasiDisposeSymbol = Symbol.for('napi.rs.wasi.dispose')
 const __wasiWorkers = new Set()
+// The thread manager has to be reachable *before* anything that can throw
+// during load or registration. Initialization can fail after the pool has
+// already spawned workers, and the rollback still has to mark their
+// terminations as expected — but `__napiModule` is assigned only when
+// instantiation RETURNS, so on exactly that path it is still undefined. A
+// plugin factory runs while the emnapi module is being created, before the
+// wasm is loaded and before any registration function runs, and its context
+// carries the very same manager instance.
+let __wasiThreadManager
+
+function __captureWasiThreadManager(context) {
+  if (context && context.PThread) {
+    __wasiThreadManager = context.PThread
+  }
+  return {}
+}
+
+function __getWasiThreadManager() {
+  const manager =
+    __wasiThreadManager !== undefined
+      ? __wasiThreadManager
+      : __napiModule
+        ? __napiModule.PThread
+        : undefined
+  if (manager && typeof manager.terminateWorker === 'function') {
+    return manager
+  }
+  return undefined
+}
 let __napiInstance
 let __emnapiContextDestroyed = false
 let __emnapiContextDestroyPromise
 let __emnapiWasmEnvCleanupPrepared = false
+let __emnapiWasmEnvCleanupPreparing = false
 let __emnapiWasmEnvCleanupRan = false
 let __emnapiWasmEnvCleanupDrained = false
 let __emnapiWasmEnvCleanupDrainPromise
@@ -119,13 +198,58 @@ function __attachCleanupErrors(error, cleanupErrors) {
   return aggregate
 }
 
+function __wrapEmnapiContextDestroyForSettlement(
+  context,
+  prepareEnvCleanup,
+  isPreparingEnvCleanup,
+) {
+  let destroy
+  try {
+    destroy = context.destroy
+  } catch {
+    return context
+  }
+  if (typeof destroy !== 'function') {
+    return context
+  }
+  try {
+    Object.defineProperty(context, 'destroy', {
+      configurable: true,
+      enumerable: false,
+      writable: true,
+      value: function () {
+        // Reentered from a promise hook that fired inside the barrier: the
+        // frame running it destroys as soon as it returns.
+        if (isPreparingEnvCleanup?.()) {
+          return
+        }
+        prepareEnvCleanup?.()
+        return Reflect.apply(destroy, this, arguments)
+      },
+    })
+  } catch {}
+  return context
+}
+
+function __isPreparingWasmEnvCleanup() {
+  return __emnapiWasmEnvCleanupPreparing
+}
+
 function __prepareWasmEnvCleanup() {
-  if (__emnapiWasmEnvCleanupPrepared) {
+  if (__emnapiWasmEnvCleanupPrepared || __emnapiWasmEnvCleanupPreparing) {
     return
   }
   const prepare = __napiInstance?.exports?.napi_prepare_wasm_env_cleanup
   if (typeof prepare === 'function') {
-    prepare()
+    // The addon settles the promises it cancels synchronously, under a
+    // non-reentrant lifecycle mutex: anything a promise hook calls from in
+    // here must not reach this export again.
+    __emnapiWasmEnvCleanupPreparing = true
+    try {
+      prepare()
+    } finally {
+      __emnapiWasmEnvCleanupPreparing = false
+    }
     __emnapiWasmEnvCleanupRan = true
   }
   __emnapiWasmEnvCleanupPrepared = true
@@ -318,13 +442,80 @@ function __destroyEmnapiContext() {
   return destroyPromise
 }
 
+/**
+ * Holds the event loop open until `work` settles.
+ *
+ * Nothing else can: the pool workers are deliberately unreferenced so an idle
+ * binding cannot keep a process alive, and referencing them again for the
+ * termination does not hold either — emnapi unreferences a worker the moment it
+ * reports `async-thread-ready`, which for a worker that was still starting
+ * lands *after* the termination began. Without a handle of its own, an
+ * `await dispose()` with nothing else pending exits the process with its
+ * promise unsettled, and everything after the `await` is skipped.
+ *
+ * The timer is cleared as soon as the work settles, so this never outlives the
+ * disposal that asked for it.
+ */
+function __keepEventLoopAliveUntil(work) {
+  const setTimer = globalThis.setInterval
+  const clearTimer = globalThis.clearInterval
+  if (typeof setTimer !== 'function' || typeof clearTimer !== 'function') {
+    return work
+  }
+  let timer
+  try {
+    timer = setTimer(function () {}, 50)
+  } catch {
+    return work
+  }
+  const release = function () {
+    try {
+      clearTimer(timer)
+    } catch {}
+  }
+  return work.then(
+    (value) => {
+      release()
+      return value
+    },
+    (error) => {
+      release()
+      throw error
+    },
+  )
+}
+
+/**
+ * `@emnapi/wasi-threads` counts a worker exit as expected only when its own
+ * thread manager performed the termination. A bare `worker.terminate()` reaches
+ * the manager's `exit` listener instead, which reports
+ * `worker (tid = N) sent an error! ... stopped with exit code 1` and rethrows
+ * inside the emit — aborting the `once('exit')` that backs the terminate
+ * promise, so disposal never settles and the process dies with an uncaught
+ * exception. Mark the termination through the manager first.
+ *
+ * The manager comes from `__getWasiThreadManager`, not from `__napiModule`:
+ * the initialization rollback runs on the one path where instantiation never
+ * returned, so `__napiModule` is still undefined there while the workers it
+ * spawned are already registered and loaded.
+ *
+ * Not `terminateAllThreads()`: that one recreates the pool it just shut down.
+ */
 function __terminateWasiWorkers() {
   const cleanupErrors = []
   const pending = []
+  const threadManager = __getWasiThreadManager()
 
   for (const worker of __wasiWorkers) {
     let result
     try {
+      if (threadManager) {
+        threadManager.terminateWorker(worker)
+        // `terminateWorker` leaves behind a reporter that logs every message
+        // still queued on the port, which Node flushes on exit. Nothing is
+        // listening for those any more.
+        worker.onmessage = undefined
+      }
       result = worker.terminate()
     } catch (error) {
       cleanupErrors.push(error)
@@ -354,7 +545,9 @@ function __terminateWasiWorkers() {
       )
     }
   }
-  return pending.length > 0 ? Promise.all(pending).then(finish) : finish()
+  return pending.length > 0
+    ? __keepEventLoopAliveUntil(Promise.all(pending)).then(finish)
+    : finish()
 }
 
 function __finishWasiDisposal() {
@@ -555,7 +748,11 @@ let __wasiModule
 let __napiModule
 
 try {
-  __emnapiContext = __emnapiCreateContext({ autoDestroy: false })
+  __emnapiContext = __wrapEmnapiContextDestroyForSettlement(
+    __emnapiCreateContext({ autoDestroy: false }),
+    __prepareWasmEnvCleanup,
+    __isPreparingWasmEnvCleanup,
+  )
   __emnapiContext.suppressDestroy()
   
   ;({
@@ -566,7 +763,7 @@ try {
     context: __emnapiContext,
     asyncWorkPoolSize: __asyncWorkPoolSize,
     reuseWorker: false,
-    plugins: [__emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
+    plugins: [__captureWasiThreadManager, __emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
     wasi: __wasi,
     onCreateWorker() {
       const worker = new Worker(new URL('./wasi-worker-browser.mjs', import.meta.url), {
@@ -596,6 +793,12 @@ try {
     },
   }))
   __publishWasiDispose(__napiModule.exports)
+  // The default export hands out this object; a named module export does not
+  // travel with it, so carry the marker on the binding itself too. After the
+  // host install, which hands the same object to addon-provided registration
+  // functions that may put anything on it, and inside this `try`, so a claimed
+  // name fails the load through the rollback below rather than past it.
+  __napiStampBindingTarget(__napiModule.exports, __napiBindingTarget)
 } catch (error) {
   const cleanupErrors = await __rollbackWasiInitialization()
   throw __attachCleanupErrors(error, cleanupErrors)

napi/transform-react/transform-react.wasi.cjs

@@ -2,6 +2,56 @@
 /* eslint-disable */
 /* auto-generated by NAPI-RS */
 
+const __napiBindingTarget = 'wasm32-wasi'
+function __napiStampBindingTarget(exportsObject, target) {
+  if (
+    Object.prototype.hasOwnProperty.call(exportsObject, '__napiBindingTarget')
+  ) {
+    if (exportsObject.__napiBindingTarget === target) {
+      // Already ours: the root entry aliases the object it loaded, so a WASI
+      // fallback candidate — or a `NAPI_RS_NATIVE_LIBRARY_PATH` override that
+      // is a generated loader — arrives already stamped with this same value.
+      return target
+    }
+    const error = new Error(
+      '`__napiBindingTarget` is reserved by the generated binding loader, but the loaded binding already exports it. Rename the export, e.g. #[napi(js_name = "...")].',
+    )
+    error.code = 'ERR_NAPI_BINDING_TARGET_CONFLICT'
+    throw error
+  }
+  if (!Object.isExtensible(exportsObject)) {
+    // A `#[napi(module_exports)]` hook may seal or freeze this object
+    // (`Object::seal` / `Object::freeze`). Reporting the artifact is metadata,
+    // never a reason to fail an otherwise successful load, so the stamp is
+    // skipped. What a consumer still sees then follows the entry point: the
+    // browser and deferred loaders declare `__napiBindingTarget` at module
+    // level and go on reporting it, while the CommonJS entries hand back this
+    // very object as `module.exports`, so there the value is absent.
+    return target
+  }
+  try {
+    // [[Define]], not [[Set]]: an ordinary assignment walks the prototype
+    // chain, so an inherited accessor could swallow the value or throw and
+    // fail an otherwise successful load. The descriptor is what a successful
+    // assignment would have produced.
+    Object.defineProperty(exportsObject, '__napiBindingTarget', {
+      configurable: true,
+      enumerable: true,
+      value: target,
+      writable: true,
+    })
+  } catch {
+    // Same rule as the non-extensible skip above: reporting the artifact is
+    // metadata, never a reason to fail an otherwise successful load. An exotic
+    // object (a Proxy whose defineProperty trap refuses) is skipped, not
+    // thrown over.
+  }
+  // The CommonJS loaders assign this return value so `cjs-module-lexer` — and
+  // therefore Node's CJS -> ESM named export detection — can see
+  // `__napiBindingTarget` statically.
+  return target
+}
+
 const __nodeFs = require('node:fs')
 const __nodePath = require('node:path')
 const { WASI: __nodeWASI } = require('node:wasi')
@@ -149,10 +199,40 @@ let __emnapiContext
 
 const __wasiDisposeSymbol = Symbol.for('napi.rs.wasi.dispose')
 const __wasiWorkers = new Set()
+// The thread manager has to be reachable *before* anything that can throw
+// during load or registration. Initialization can fail after the pool has
+// already spawned workers, and the rollback still has to mark their
+// terminations as expected — but `__napiModule` is assigned only when
+// instantiation RETURNS, so on exactly that path it is still undefined. A
+// plugin factory runs while the emnapi module is being created, before the
+// wasm is loaded and before any registration function runs, and its context
+// carries the very same manager instance.
+let __wasiThreadManager
+
+function __captureWasiThreadManager(context) {
+  if (context && context.PThread) {
+    __wasiThreadManager = context.PThread
+  }
+  return {}
+}
+
+function __getWasiThreadManager() {
+  const manager =
+    __wasiThreadManager !== undefined
+      ? __wasiThreadManager
+      : __napiModule
+        ? __napiModule.PThread
+        : undefined
+  if (manager && typeof manager.terminateWorker === 'function') {
+    return manager
+  }
+  return undefined
+}
 let __napiInstance
 let __emnapiContextDestroyed = false
 let __emnapiContextDestroyPromise
 let __emnapiWasmEnvCleanupPrepared = false
+let __emnapiWasmEnvCleanupPreparing = false
 let __emnapiWasmEnvCleanupRan = false
 let __emnapiWasmEnvCleanupDrained = false
 let __emnapiWasmEnvCleanupDrainPromise
@@ -226,13 +306,58 @@ function __attachCleanupErrors(error, cleanupErrors) {
   return aggregate
 }
 
+function __wrapEmnapiContextDestroyForSettlement(
+  context,
+  prepareEnvCleanup,
+  isPreparingEnvCleanup,
+) {
+  let destroy
+  try {
+    destroy = context.destroy
+  } catch {
+    return context
+  }
+  if (typeof destroy !== 'function') {
+    return context
+  }
+  try {
+    Object.defineProperty(context, 'destroy', {
+      configurable: true,
+      enumerable: false,
+      writable: true,
+      value: function () {
+        // Reentered from a promise hook that fired inside the barrier: the
+        // frame running it destroys as soon as it returns.
+        if (isPreparingEnvCleanup?.()) {
+          return
+        }
+        prepareEnvCleanup?.()
+        return Reflect.apply(destroy, this, arguments)
+      },
+    })
+  } catch {}
+  return context
+}
+
+function __isPreparingWasmEnvCleanup() {
+  return __emnapiWasmEnvCleanupPreparing
+}
+
 function __prepareWasmEnvCleanup() {
-  if (__emnapiWasmEnvCleanupPrepared) {
+  if (__emnapiWasmEnvCleanupPrepared || __emnapiWasmEnvCleanupPreparing) {
     return
   }
   const prepare = __napiInstance?.exports?.napi_prepare_wasm_env_cleanup
   if (typeof prepare === 'function') {
-    prepare()
+    // The addon settles the promises it cancels synchronously, under a
+    // non-reentrant lifecycle mutex: anything a promise hook calls from in
+    // here must not reach this export again.
+    __emnapiWasmEnvCleanupPreparing = true
+    try {
+      prepare()
+    } finally {
+      __emnapiWasmEnvCleanupPreparing = false
+    }
     __emnapiWasmEnvCleanupRan = true
   }
   __emnapiWasmEnvCleanupPrepared = true
@@ -425,13 +550,80 @@ function __destroyEmnapiContext() {
   return destroyPromise
 }
 
+/**
+ * Holds the event loop open until `work` settles.
+ *
+ * Nothing else can: the pool workers are deliberately unreferenced so an idle
+ * binding cannot keep a process alive, and referencing them again for the
+ * termination does not hold either — emnapi unreferences a worker the moment it
+ * reports `async-thread-ready`, which for a worker that was still starting
+ * lands *after* the termination began. Without a handle of its own, an
+ * `await dispose()` with nothing else pending exits the process with its
+ * promise unsettled, and everything after the `await` is skipped.
+ *
+ * The timer is cleared as soon as the work settles, so this never outlives the
+ * disposal that asked for it.
+ */
+function __keepEventLoopAliveUntil(work) {
+  const setTimer = globalThis.setInterval
+  const clearTimer = globalThis.clearInterval
+  if (typeof setTimer !== 'function' || typeof clearTimer !== 'function') {
+    return work
+  }
+  let timer
+  try {
+    timer = setTimer(function () {}, 50)
+  } catch {
+    return work
+  }
+  const release = function () {
+    try {
+      clearTimer(timer)
+    } catch {}
+  }
+  return work.then(
+    (value) => {
+      release()
+      return value
+    },
+    (error) => {
+      release()
+      throw error
+    },
+  )
+}
+
+/**
+ * `@emnapi/wasi-threads` counts a worker exit as expected only when its own
+ * thread manager performed the termination. A bare `worker.terminate()` reaches
+ * the manager's `exit` listener instead, which reports
+ * `worker (tid = N) sent an error! ... stopped with exit code 1` and rethrows
+ * inside the emit — aborting the `once('exit')` that backs the terminate
+ * promise, so disposal never settles and the process dies with an uncaught
+ * exception. Mark the termination through the manager first.
+ *
+ * The manager comes from `__getWasiThreadManager`, not from `__napiModule`:
+ * the initialization rollback runs on the one path where instantiation never
+ * returned, so `__napiModule` is still undefined there while the workers it
+ * spawned are already registered and loaded.
+ *
+ * Not `terminateAllThreads()`: that one recreates the pool it just shut down.
+ */
 function __terminateWasiWorkers() {
   const cleanupErrors = []
   const pending = []
+  const threadManager = __getWasiThreadManager()
 
   for (const worker of __wasiWorkers) {
     let result
     try {
+      if (threadManager) {
+        threadManager.terminateWorker(worker)
+        // `terminateWorker` leaves behind a reporter that logs every message
+        // still queued on the port, which Node flushes on exit. Nothing is
+        // listening for those any more.
+        worker.onmessage = undefined
+      }
       result = worker.terminate()
     } catch (error) {
       cleanupErrors.push(error)
@@ -461,7 +653,9 @@ function __terminateWasiWorkers() {
       )
     }
   }
-  return pending.length > 0 ? Promise.all(pending).then(finish) : finish()
+  return pending.length > 0
+    ? __keepEventLoopAliveUntil(Promise.all(pending)).then(finish)
+    : finish()
 }
 
 function __finishWasiDisposal() {
@@ -831,7 +1025,11 @@ function __captureEmnapiAutoDestroyListener() {
 try {
   const __finishAutoDestroyCapture = __captureEmnapiAutoDestroyListener()
   try {
-    __emnapiContext = __emnapiCreateContext({ autoDestroy: false })
+    __emnapiContext = __wrapEmnapiContextDestroyForSettlement(
+      __emnapiCreateContext({ autoDestroy: false }),
+      __prepareWasmEnvCleanup,
+      __isPreparingWasmEnvCleanup,
+    )
     // emnapi 2.x still registers an unconditional once-listener for
     // beforeExit that auto-destroys the context, and suppressDestroy() only
     // neutralizes its callback without removing it. This loader owns cleanup
@@ -859,7 +1057,7 @@ try {
       }
     })(),
     reuseWorker: true,
-    plugins: [__emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
+    plugins: [__captureWasiThreadManager, __emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
     wasi: __wasi,
     onCreateWorker() {
       const worker = __createWasiWorker(__nodePath.join(__dirname, 'wasi-worker.mjs'))
@@ -889,6 +1087,10 @@ try {
         }
 
         worker.unref()
+        // These stubs stay in place for the worker's whole life, disposal
+        // included: `__keepEventLoopAliveUntil` is what holds the process open
+        // while a termination is pending, precisely because a worker's own
+        // references cannot be relied on for it.
       }
       return worker
     },
@@ -911,6 +1113,22 @@ try {
     },
   }))
   __publishWasiDispose(__napiModule.exports)
+  // The CommonJS tail below aliases `__napiModule.exports`; a named module
+  // export does not travel with it, so carry the marker on the binding itself
+  // too. Three things pin the stamp to exactly this spot:
+  //   - inside this `try`, because the guard throws on a
+  //     `#[napi(module_exports)]` hook that claimed the name, and only the
+  //     catch below tears the environment — context, workers, exit listener —
+  //     back down;
+  //   - after the async runtime host install, which hands this same object to
+  //     addon-provided registration functions that may put anything on it;
+  //   - assigning onto the loader's own `module.exports`, which is still the
+  //     original object here, so an addon accessor with a refusing setter is
+  //     never written through. `cjs-module-lexer` — Node's CJS -> ESM named
+  //     export detection — reads the static `module.exports.<name> =` either
+  //     way, and the later `module.exports = __napiModule.exports` does not
+  //     undo that.
+  module.exports.__napiBindingTarget = __napiStampBindingTarget(__napiModule.exports, __napiBindingTarget)
   __registerWasiExitListener()
 } catch (error) {
   const rollback = {

napi/transform-react/transform-react.wasi.d.cts

@@ -1,6 +1,9 @@
 /* auto-generated by NAPI-RS */
 /* eslint-disable */
 
+/** The WASI flavor this loader instantiates. */
+export declare const __napiBindingTarget: 'wasm32-wasi'
+
 export interface Comment {
   type: 'Line' | 'Block'
   value: string

napi/transform-relay/index.d.ts

@@ -1,6 +1,14 @@
 /* auto-generated by NAPI-RS */
 /* eslint-disable */
 
+/**
+ * Which binding artifact the generated loader actually loaded: `'native'` for
+ * a native addon, otherwise the `platformArchABI` of the WASI flavor. Every
+ * flavor napi-rs can build is listed, because `NAPI_RS_NATIVE_LIBRARY_PATH`
+ * can point the loader at a WASI artifact this package does not build itself.
+ */
+export declare const __napiBindingTarget: 'native' | 'wasm32-wasi' | 'wasm32-wasip1'
+
 export interface Comment {
   type: 'Line' | 'Block'
   value: string

napi/transform-relay/index.js

@@ -7,6 +7,10 @@ const require = createRequire(import.meta.url)
 
 const { readFileSync } = require('fs')
 let nativeBinding = null
+// Which artifact actually loaded. The WASI fallback chain overwrites it with
+// the flavor it resolved; the late native retry below leaves it alone because
+// it only runs while no WASI candidate has been loaded.
+let __napiLoadedBindingTarget = 'native'
 const loadErrors = []
 
 const isMusl = () => {
@@ -65,7 +69,16 @@ const isMuslFromChildProcess = () => {
 function requireNative() {
   if (process.env.NAPI_RS_NATIVE_LIBRARY_PATH) {
     try {
-      return require(process.env.NAPI_RS_NATIVE_LIBRARY_PATH)
+      const overrideBinding = require(process.env.NAPI_RS_NATIVE_LIBRARY_PATH)
+      // The override may be a generated WASI loader, which already reports its
+      // own flavor. Adopt it: `module.exports` aliases this object, so claiming
+      // 'native' would both misreport the artifact and overwrite the loader's
+      // marker through the alias.
+      __napiLoadedBindingTarget =
+        overrideBinding && typeof overrideBinding.__napiBindingTarget === 'string'
+          ? overrideBinding.__napiBindingTarget
+          : 'native'
+      return overrideBinding
     } catch (err) {
       loadErrors.push(err)
     }
@@ -630,6 +643,7 @@ if (!nativeBinding || forceWasi) {
       if (!candidateFailed) {
         wasiBinding = require('./transform-relay.wasi.cjs')
         nativeBinding = wasiBinding
+        __napiLoadedBindingTarget = 'wasm32-wasi'
         wasiBindingLoaded = true
       }
     } catch (err) {
@@ -656,6 +670,7 @@ if (!nativeBinding || forceWasi) {
         }
         wasiBinding = require('@oxc-transform-relay/binding-wasm32-wasi')
         nativeBinding = wasiBinding
+        __napiLoadedBindingTarget = 'wasm32-wasi'
         wasiBindingLoaded = true
       }
     } catch (err) {
@@ -713,3 +728,4 @@ const { Severity, transform, transformSync } = nativeBinding
 export { Severity }
 export { transform }
 export { transformSync }
+export const __napiBindingTarget = __napiLoadedBindingTarget

napi/transform-relay/transform-relay.wasi-browser.js

@@ -8,6 +8,55 @@ import {
 import { createContext as __emnapiCreateContext } from '@emnapi/runtime'
 
 
+export const __napiBindingTarget = 'wasm32-wasi'
+function __napiStampBindingTarget(exportsObject, target) {
+  if (
+    Object.prototype.hasOwnProperty.call(exportsObject, '__napiBindingTarget')
+  ) {
+    if (exportsObject.__napiBindingTarget === target) {
+      // Already ours: the root entry aliases the object it loaded, so a WASI
+      // fallback candidate — or a `NAPI_RS_NATIVE_LIBRARY_PATH` override that
+      // is a generated loader — arrives already stamped with this same value.
+      return target
+    }
+    const error = new Error(
+      '`__napiBindingTarget` is reserved by the generated binding loader, but the loaded binding already exports it. Rename the export, e.g. #[napi(js_name = "...")].',
+    )
+    error.code = 'ERR_NAPI_BINDING_TARGET_CONFLICT'
+    throw error
+  }
+  if (!Object.isExtensible(exportsObject)) {
+    // A `#[napi(module_exports)]` hook may seal or freeze this object
+    // (`Object::seal` / `Object::freeze`). Reporting the artifact is metadata,
+    // never a reason to fail an otherwise successful load, so the stamp is
+    // skipped. What a consumer still sees then follows the entry point: the
+    // browser and deferred loaders declare `__napiBindingTarget` at module
+    // level and go on reporting it, while the CommonJS entries hand back this
+    // very object as `module.exports`, so there the value is absent.
+    return target
+  }
+  try {
+    // [[Define]], not [[Set]]: an ordinary assignment walks the prototype
+    // chain, so an inherited accessor could swallow the value or throw and
+    // fail an otherwise successful load. The descriptor is what a successful
+    // assignment would have produced.
+    Object.defineProperty(exportsObject, '__napiBindingTarget', {
+      configurable: true,
+      enumerable: true,
+      value: target,
+      writable: true,
+    })
+  } catch {
+    // Same rule as the non-extensible skip above: reporting the artifact is
+    // metadata, never a reason to fail an otherwise successful load. An exotic
+    // object (a Proxy whose defineProperty trap refuses) is skipped, not
+    // thrown over.
+  }
+  // The CommonJS loaders assign this return value so `cjs-module-lexer` — and
+  // therefore Node's CJS -> ESM named export detection — can see
+  // `__napiBindingTarget` statically.
+  return target
+}
 
 const __wasi = new __WASI({
   version: 'preview1',
@@ -42,10 +91,40 @@ let __emnapiContext
 
 const __wasiDisposeSymbol = Symbol.for('napi.rs.wasi.dispose')
 const __wasiWorkers = new Set()
+// The thread manager has to be reachable *before* anything that can throw
+// during load or registration. Initialization can fail after the pool has
+// already spawned workers, and the rollback still has to mark their
+// terminations as expected — but `__napiModule` is assigned only when
+// instantiation RETURNS, so on exactly that path it is still undefined. A
+// plugin factory runs while the emnapi module is being created, before the
+// wasm is loaded and before any registration function runs, and its context
+// carries the very same manager instance.
+let __wasiThreadManager
+
+function __captureWasiThreadManager(context) {
+  if (context && context.PThread) {
+    __wasiThreadManager = context.PThread
+  }
+  return {}
+}
+
+function __getWasiThreadManager() {
+  const manager =
+    __wasiThreadManager !== undefined
+      ? __wasiThreadManager
+      : __napiModule
+        ? __napiModule.PThread
+        : undefined
+  if (manager && typeof manager.terminateWorker === 'function') {
+    return manager
+  }
+  return undefined
+}
 let __napiInstance
 let __emnapiContextDestroyed = false
 let __emnapiContextDestroyPromise
 let __emnapiWasmEnvCleanupPrepared = false
+let __emnapiWasmEnvCleanupPreparing = false
 let __emnapiWasmEnvCleanupRan = false
 let __emnapiWasmEnvCleanupDrained = false
 let __emnapiWasmEnvCleanupDrainPromise
@@ -119,13 +198,58 @@ function __attachCleanupErrors(error, cleanupErrors) {
   return aggregate
 }
 
+function __wrapEmnapiContextDestroyForSettlement(
+  context,
+  prepareEnvCleanup,
+  isPreparingEnvCleanup,
+) {
+  let destroy
+  try {
+    destroy = context.destroy
+  } catch {
+    return context
+  }
+  if (typeof destroy !== 'function') {
+    return context
+  }
+  try {
+    Object.defineProperty(context, 'destroy', {
+      configurable: true,
+      enumerable: false,
+      writable: true,
+      value: function () {
+        // Reentered from a promise hook that fired inside the barrier: the
+        // frame running it destroys as soon as it returns.
+        if (isPreparingEnvCleanup?.()) {
+          return
+        }
+        prepareEnvCleanup?.()
+        return Reflect.apply(destroy, this, arguments)
+      },
+    })
+  } catch {}
+  return context
+}
+
+function __isPreparingWasmEnvCleanup() {
+  return __emnapiWasmEnvCleanupPreparing
+}
+
 function __prepareWasmEnvCleanup() {
-  if (__emnapiWasmEnvCleanupPrepared) {
+  if (__emnapiWasmEnvCleanupPrepared || __emnapiWasmEnvCleanupPreparing) {
     return
   }
   const prepare = __napiInstance?.exports?.napi_prepare_wasm_env_cleanup
   if (typeof prepare === 'function') {
-    prepare()
+    // The addon settles the promises it cancels synchronously, under a
+    // non-reentrant lifecycle mutex: anything a promise hook calls from in
+    // here must not reach this export again.
+    __emnapiWasmEnvCleanupPreparing = true
+    try {
+      prepare()
+    } finally {
+      __emnapiWasmEnvCleanupPreparing = false
+    }
     __emnapiWasmEnvCleanupRan = true
   }
   __emnapiWasmEnvCleanupPrepared = true
@@ -318,13 +442,80 @@ function __destroyEmnapiContext() {
   return destroyPromise
 }
 
+/**
+ * Holds the event loop open until `work` settles.
+ *
+ * Nothing else can: the pool workers are deliberately unreferenced so an idle
+ * binding cannot keep a process alive, and referencing them again for the
+ * termination does not hold either — emnapi unreferences a worker the moment it
+ * reports `async-thread-ready`, which for a worker that was still starting
+ * lands *after* the termination began. Without a handle of its own, an
+ * `await dispose()` with nothing else pending exits the process with its
+ * promise unsettled, and everything after the `await` is skipped.
+ *
+ * The timer is cleared as soon as the work settles, so this never outlives the
+ * disposal that asked for it.
+ */
+function __keepEventLoopAliveUntil(work) {
+  const setTimer = globalThis.setInterval
+  const clearTimer = globalThis.clearInterval
+  if (typeof setTimer !== 'function' || typeof clearTimer !== 'function') {
+    return work
+  }
+  let timer
+  try {
+    timer = setTimer(function () {}, 50)
+  } catch {
+    return work
+  }
+  const release = function () {
+    try {
+      clearTimer(timer)
+    } catch {}
+  }
+  return work.then(
+    (value) => {
+      release()
+      return value
+    },
+    (error) => {
+      release()
+      throw error
+    },
+  )
+}
+
+/**
+ * `@emnapi/wasi-threads` counts a worker exit as expected only when its own
+ * thread manager performed the termination. A bare `worker.terminate()` reaches
+ * the manager's `exit` listener instead, which reports
+ * `worker (tid = N) sent an error! ... stopped with exit code 1` and rethrows
+ * inside the emit — aborting the `once('exit')` that backs the terminate
+ * promise, so disposal never settles and the process dies with an uncaught
+ * exception. Mark the termination through the manager first.
+ *
+ * The manager comes from `__getWasiThreadManager`, not from `__napiModule`:
+ * the initialization rollback runs on the one path where instantiation never
+ * returned, so `__napiModule` is still undefined there while the workers it
+ * spawned are already registered and loaded.
+ *
+ * Not `terminateAllThreads()`: that one recreates the pool it just shut down.
+ */
 function __terminateWasiWorkers() {
   const cleanupErrors = []
   const pending = []
+  const threadManager = __getWasiThreadManager()
 
   for (const worker of __wasiWorkers) {
     let result
     try {
+      if (threadManager) {
+        threadManager.terminateWorker(worker)
+        // `terminateWorker` leaves behind a reporter that logs every message
+        // still queued on the port, which Node flushes on exit. Nothing is
+        // listening for those any more.
+        worker.onmessage = undefined
+      }
       result = worker.terminate()
     } catch (error) {
       cleanupErrors.push(error)
@@ -354,7 +545,9 @@ function __terminateWasiWorkers() {
       )
     }
   }
-  return pending.length > 0 ? Promise.all(pending).then(finish) : finish()
+  return pending.length > 0
+    ? __keepEventLoopAliveUntil(Promise.all(pending)).then(finish)
+    : finish()
 }
 
 function __finishWasiDisposal() {
@@ -555,7 +748,11 @@ let __wasiModule
 let __napiModule
 
 try {
-  __emnapiContext = __emnapiCreateContext({ autoDestroy: false })
+  __emnapiContext = __wrapEmnapiContextDestroyForSettlement(
+    __emnapiCreateContext({ autoDestroy: false }),
+    __prepareWasmEnvCleanup,
+    __isPreparingWasmEnvCleanup,
+  )
   __emnapiContext.suppressDestroy()
   
   ;({
@@ -566,7 +763,7 @@ try {
     context: __emnapiContext,
     asyncWorkPoolSize: __asyncWorkPoolSize,
     reuseWorker: false,
-    plugins: [__emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
+    plugins: [__captureWasiThreadManager, __emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
     wasi: __wasi,
     onCreateWorker() {
       const worker = new Worker(new URL('./wasi-worker-browser.mjs', import.meta.url), {
@@ -596,6 +793,12 @@ try {
     },
   }))
   __publishWasiDispose(__napiModule.exports)
+  // The default export hands out this object; a named module export does not
+  // travel with it, so carry the marker on the binding itself too. After the
+  // host install, which hands the same object to addon-provided registration
+  // functions that may put anything on it, and inside this `try`, so a claimed
+  // name fails the load through the rollback below rather than past it.
+  __napiStampBindingTarget(__napiModule.exports, __napiBindingTarget)
 } catch (error) {
   const cleanupErrors = await __rollbackWasiInitialization()
   throw __attachCleanupErrors(error, cleanupErrors)

napi/transform-relay/transform-relay.wasi.cjs

@@ -2,6 +2,56 @@
 /* eslint-disable */
 /* auto-generated by NAPI-RS */
 
+const __napiBindingTarget = 'wasm32-wasi'
+function __napiStampBindingTarget(exportsObject, target) {
+  if (
+    Object.prototype.hasOwnProperty.call(exportsObject, '__napiBindingTarget')
+  ) {
+    if (exportsObject.__napiBindingTarget === target) {
+      // Already ours: the root entry aliases the object it loaded, so a WASI
+      // fallback candidate — or a `NAPI_RS_NATIVE_LIBRARY_PATH` override that
+      // is a generated loader — arrives already stamped with this same value.
+      return target
+    }
+    const error = new Error(
+      '`__napiBindingTarget` is reserved by the generated binding loader, but the loaded binding already exports it. Rename the export, e.g. #[napi(js_name = "...")].',
+    )
+    error.code = 'ERR_NAPI_BINDING_TARGET_CONFLICT'
+    throw error
+  }
+  if (!Object.isExtensible(exportsObject)) {
+    // A `#[napi(module_exports)]` hook may seal or freeze this object
+    // (`Object::seal` / `Object::freeze`). Reporting the artifact is metadata,
+    // never a reason to fail an otherwise successful load, so the stamp is
+    // skipped. What a consumer still sees then follows the entry point: the
+    // browser and deferred loaders declare `__napiBindingTarget` at module
+    // level and go on reporting it, while the CommonJS entries hand back this
+    // very object as `module.exports`, so there the value is absent.
+    return target
+  }
+  try {
+    // [[Define]], not [[Set]]: an ordinary assignment walks the prototype
+    // chain, so an inherited accessor could swallow the value or throw and
+    // fail an otherwise successful load. The descriptor is what a successful
+    // assignment would have produced.
+    Object.defineProperty(exportsObject, '__napiBindingTarget', {
+      configurable: true,
+      enumerable: true,
+      value: target,
+      writable: true,
+    })
+  } catch {
+    // Same rule as the non-extensible skip above: reporting the artifact is
+    // metadata, never a reason to fail an otherwise successful load. An exotic
+    // object (a Proxy whose defineProperty trap refuses) is skipped, not
+    // thrown over.
+  }
+  // The CommonJS loaders assign this return value so `cjs-module-lexer` — and
+  // therefore Node's CJS -> ESM named export detection — can see
+  // `__napiBindingTarget` statically.
+  return target
+}
+
 const __nodeFs = require('node:fs')
 const __nodePath = require('node:path')
 const { WASI: __nodeWASI } = require('node:wasi')
@@ -149,10 +199,40 @@ let __emnapiContext
 
 const __wasiDisposeSymbol = Symbol.for('napi.rs.wasi.dispose')
 const __wasiWorkers = new Set()
+// The thread manager has to be reachable *before* anything that can throw
+// during load or registration. Initialization can fail after the pool has
+// already spawned workers, and the rollback still has to mark their
+// terminations as expected — but `__napiModule` is assigned only when
+// instantiation RETURNS, so on exactly that path it is still undefined. A
+// plugin factory runs while the emnapi module is being created, before the
+// wasm is loaded and before any registration function runs, and its context
+// carries the very same manager instance.
+let __wasiThreadManager
+
+function __captureWasiThreadManager(context) {
+  if (context && context.PThread) {
+    __wasiThreadManager = context.PThread
+  }
+  return {}
+}
+
+function __getWasiThreadManager() {
+  const manager =
+    __wasiThreadManager !== undefined
+      ? __wasiThreadManager
+      : __napiModule
+        ? __napiModule.PThread
+        : undefined
+  if (manager && typeof manager.terminateWorker === 'function') {
+    return manager
+  }
+  return undefined
+}
 let __napiInstance
 let __emnapiContextDestroyed = false
 let __emnapiContextDestroyPromise
 let __emnapiWasmEnvCleanupPrepared = false
+let __emnapiWasmEnvCleanupPreparing = false
 let __emnapiWasmEnvCleanupRan = false
 let __emnapiWasmEnvCleanupDrained = false
 let __emnapiWasmEnvCleanupDrainPromise
@@ -226,13 +306,58 @@ function __attachCleanupErrors(error, cleanupErrors) {
   return aggregate
 }
 
+function __wrapEmnapiContextDestroyForSettlement(
+  context,
+  prepareEnvCleanup,
+  isPreparingEnvCleanup,
+) {
+  let destroy
+  try {
+    destroy = context.destroy
+  } catch {
+    return context
+  }
+  if (typeof destroy !== 'function') {
+    return context
+  }
+  try {
+    Object.defineProperty(context, 'destroy', {
+      configurable: true,
+      enumerable: false,
+      writable: true,
+      value: function () {
+        // Reentered from a promise hook that fired inside the barrier: the
+        // frame running it destroys as soon as it returns.
+        if (isPreparingEnvCleanup?.()) {
+          return
+        }
+        prepareEnvCleanup?.()
+        return Reflect.apply(destroy, this, arguments)
+      },
+    })
+  } catch {}
+  return context
+}
+
+function __isPreparingWasmEnvCleanup() {
+  return __emnapiWasmEnvCleanupPreparing
+}
+
 function __prepareWasmEnvCleanup() {
-  if (__emnapiWasmEnvCleanupPrepared) {
+  if (__emnapiWasmEnvCleanupPrepared || __emnapiWasmEnvCleanupPreparing) {
     return
   }
   const prepare = __napiInstance?.exports?.napi_prepare_wasm_env_cleanup
   if (typeof prepare === 'function') {
-    prepare()
+    // The addon settles the promises it cancels synchronously, under a
+    // non-reentrant lifecycle mutex: anything a promise hook calls from in
+    // here must not reach this export again.
+    __emnapiWasmEnvCleanupPreparing = true
+    try {
+      prepare()
+    } finally {
+      __emnapiWasmEnvCleanupPreparing = false
+    }
     __emnapiWasmEnvCleanupRan = true
   }
   __emnapiWasmEnvCleanupPrepared = true
@@ -425,13 +550,80 @@ function __destroyEmnapiContext() {
   return destroyPromise
 }
 
+/**
+ * Holds the event loop open until `work` settles.
+ *
+ * Nothing else can: the pool workers are deliberately unreferenced so an idle
+ * binding cannot keep a process alive, and referencing them again for the
+ * termination does not hold either — emnapi unreferences a worker the moment it
+ * reports `async-thread-ready`, which for a worker that was still starting
+ * lands *after* the termination began. Without a handle of its own, an
+ * `await dispose()` with nothing else pending exits the process with its
+ * promise unsettled, and everything after the `await` is skipped.
+ *
+ * The timer is cleared as soon as the work settles, so this never outlives the
+ * disposal that asked for it.
+ */
+function __keepEventLoopAliveUntil(work) {
+  const setTimer = globalThis.setInterval
+  const clearTimer = globalThis.clearInterval
+  if (typeof setTimer !== 'function' || typeof clearTimer !== 'function') {
+    return work
+  }
+  let timer
+  try {
+    timer = setTimer(function () {}, 50)
+  } catch {
+    return work
+  }
+  const release = function () {
+    try {
+      clearTimer(timer)
+    } catch {}
+  }
+  return work.then(
+    (value) => {
+      release()
+      return value
+    },
+    (error) => {
+      release()
+      throw error
+    },
+  )
+}
+
+/**
+ * `@emnapi/wasi-threads` counts a worker exit as expected only when its own
+ * thread manager performed the termination. A bare `worker.terminate()` reaches
+ * the manager's `exit` listener instead, which reports
+ * `worker (tid = N) sent an error! ... stopped with exit code 1` and rethrows
+ * inside the emit — aborting the `once('exit')` that backs the terminate
+ * promise, so disposal never settles and the process dies with an uncaught
+ * exception. Mark the termination through the manager first.
+ *
+ * The manager comes from `__getWasiThreadManager`, not from `__napiModule`:
+ * the initialization rollback runs on the one path where instantiation never
+ * returned, so `__napiModule` is still undefined there while the workers it
+ * spawned are already registered and loaded.
+ *
+ * Not `terminateAllThreads()`: that one recreates the pool it just shut down.
+ */
 function __terminateWasiWorkers() {
   const cleanupErrors = []
   const pending = []
+  const threadManager = __getWasiThreadManager()
 
   for (const worker of __wasiWorkers) {
     let result
     try {
+      if (threadManager) {
+        threadManager.terminateWorker(worker)
+        // `terminateWorker` leaves behind a reporter that logs every message
+        // still queued on the port, which Node flushes on exit. Nothing is
+        // listening for those any more.
+        worker.onmessage = undefined
+      }
       result = worker.terminate()
     } catch (error) {
       cleanupErrors.push(error)
@@ -461,7 +653,9 @@ function __terminateWasiWorkers() {
       )
     }
   }
-  return pending.length > 0 ? Promise.all(pending).then(finish) : finish()
+  return pending.length > 0
+    ? __keepEventLoopAliveUntil(Promise.all(pending)).then(finish)
+    : finish()
 }
 
 function __finishWasiDisposal() {
@@ -831,7 +1025,11 @@ function __captureEmnapiAutoDestroyListener() {
 try {
   const __finishAutoDestroyCapture = __captureEmnapiAutoDestroyListener()
   try {
-    __emnapiContext = __emnapiCreateContext({ autoDestroy: false })
+    __emnapiContext = __wrapEmnapiContextDestroyForSettlement(
+      __emnapiCreateContext({ autoDestroy: false }),
+      __prepareWasmEnvCleanup,
+      __isPreparingWasmEnvCleanup,
+    )
     // emnapi 2.x still registers an unconditional once-listener for
     // beforeExit that auto-destroys the context, and suppressDestroy() only
     // neutralizes its callback without removing it. This loader owns cleanup
@@ -859,7 +1057,7 @@ try {
       }
     })(),
     reuseWorker: true,
-    plugins: [__emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
+    plugins: [__captureWasiThreadManager, __emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
     wasi: __wasi,
     onCreateWorker() {
       const worker = __createWasiWorker(__nodePath.join(__dirname, 'wasi-worker.mjs'))
@@ -889,6 +1087,10 @@ try {
         }
 
         worker.unref()
+        // These stubs stay in place for the worker's whole life, disposal
+        // included: `__keepEventLoopAliveUntil` is what holds the process open
+        // while a termination is pending, precisely because a worker's own
+        // references cannot be relied on for it.
       }
       return worker
     },
@@ -911,6 +1113,22 @@ try {
     },
   }))
   __publishWasiDispose(__napiModule.exports)
+  // The CommonJS tail below aliases `__napiModule.exports`; a named module
+  // export does not travel with it, so carry the marker on the binding itself
+  // too. Three things pin the stamp to exactly this spot:
+  //   - inside this `try`, because the guard throws on a
+  //     `#[napi(module_exports)]` hook that claimed the name, and only the
+  //     catch below tears the environment — context, workers, exit listener —
+  //     back down;
+  //   - after the async runtime host install, which hands this same object to
+  //     addon-provided registration functions that may put anything on it;
+  //   - assigning onto the loader's own `module.exports`, which is still the
+  //     original object here, so an addon accessor with a refusing setter is
+  //     never written through. `cjs-module-lexer` — Node's CJS -> ESM named
+  //     export detection — reads the static `module.exports.<name> =` either
+  //     way, and the later `module.exports = __napiModule.exports` does not
+  //     undo that.
+  module.exports.__napiBindingTarget = __napiStampBindingTarget(__napiModule.exports, __napiBindingTarget)
   __registerWasiExitListener()
 } catch (error) {
   const rollback = {

napi/transform-relay/transform-relay.wasi.d.cts

@@ -1,6 +1,9 @@
 /* auto-generated by NAPI-RS */
 /* eslint-disable */
 
+/** The WASI flavor this loader instantiates. */
+export declare const __napiBindingTarget: 'wasm32-wasi'
+
 export interface Comment {
   type: 'Line' | 'Block'
   value: string

napi/transform/index.d.ts

@@ -1,6 +1,14 @@
 /* auto-generated by NAPI-RS */
 /* eslint-disable */
 
+/**
+ * Which binding artifact the generated loader actually loaded: `'native'` for
+ * a native addon, otherwise the `platformArchABI` of the WASI flavor. Every
+ * flavor napi-rs can build is listed, because `NAPI_RS_NATIVE_LIBRARY_PATH`
+ * can point the loader at a WASI artifact this package does not build itself.
+ */
+export declare const __napiBindingTarget: 'native' | 'wasm32-wasi' | 'wasm32-wasip1'
+
 export interface Comment {
   type: 'Line' | 'Block'
   value: string

napi/transform/index.js

@@ -7,6 +7,10 @@ const require = createRequire(import.meta.url)
 
 const { readFileSync } = require('fs')
 let nativeBinding = null
+// Which artifact actually loaded. The WASI fallback chain overwrites it with
+// the flavor it resolved; the late native retry below leaves it alone because
+// it only runs while no WASI candidate has been loaded.
+let __napiLoadedBindingTarget = 'native'
 const loadErrors = []
 
 const isMusl = () => {
@@ -65,7 +69,16 @@ const isMuslFromChildProcess = () => {
 function requireNative() {
   if (process.env.NAPI_RS_NATIVE_LIBRARY_PATH) {
     try {
-      return require(process.env.NAPI_RS_NATIVE_LIBRARY_PATH)
+      const overrideBinding = require(process.env.NAPI_RS_NATIVE_LIBRARY_PATH)
+      // The override may be a generated WASI loader, which already reports its
+      // own flavor. Adopt it: `module.exports` aliases this object, so claiming
+      // 'native' would both misreport the artifact and overwrite the loader's
+      // marker through the alias.
+      __napiLoadedBindingTarget =
+        overrideBinding && typeof overrideBinding.__napiBindingTarget === 'string'
+          ? overrideBinding.__napiBindingTarget
+          : 'native'
+      return overrideBinding
     } catch (err) {
       loadErrors.push(err)
     }
@@ -630,6 +643,7 @@ if (!nativeBinding || forceWasi) {
       if (!candidateFailed) {
         wasiBinding = require('./transform.wasi.cjs')
         nativeBinding = wasiBinding
+        __napiLoadedBindingTarget = 'wasm32-wasi'
         wasiBindingLoaded = true
       }
     } catch (err) {
@@ -656,6 +670,7 @@ if (!nativeBinding || forceWasi) {
         }
         wasiBinding = require('@oxc-transform/binding-wasm32-wasi')
         nativeBinding = wasiBinding
+        __napiLoadedBindingTarget = 'wasm32-wasi'
         wasiBindingLoaded = true
       }
     } catch (err) {
@@ -718,3 +733,4 @@ export { moduleRunnerTransform }
 export { moduleRunnerTransformSync }
 export { transform }
 export { transformSync }
+export const __napiBindingTarget = __napiLoadedBindingTarget

napi/transform/transform.wasi-browser.js

@@ -8,6 +8,55 @@ import {
 import { createContext as __emnapiCreateContext } from '@emnapi/runtime'
 
 
+export const __napiBindingTarget = 'wasm32-wasi'
+function __napiStampBindingTarget(exportsObject, target) {
+  if (
+    Object.prototype.hasOwnProperty.call(exportsObject, '__napiBindingTarget')
+  ) {
+    if (exportsObject.__napiBindingTarget === target) {
+      // Already ours: the root entry aliases the object it loaded, so a WASI
+      // fallback candidate — or a `NAPI_RS_NATIVE_LIBRARY_PATH` override that
+      // is a generated loader — arrives already stamped with this same value.
+      return target
+    }
+    const error = new Error(
+      '`__napiBindingTarget` is reserved by the generated binding loader, but the loaded binding already exports it. Rename the export, e.g. #[napi(js_name = "...")].',
+    )
+    error.code = 'ERR_NAPI_BINDING_TARGET_CONFLICT'
+    throw error
+  }
+  if (!Object.isExtensible(exportsObject)) {
+    // A `#[napi(module_exports)]` hook may seal or freeze this object
+    // (`Object::seal` / `Object::freeze`). Reporting the artifact is metadata,
+    // never a reason to fail an otherwise successful load, so the stamp is
+    // skipped. What a consumer still sees then follows the entry point: the
+    // browser and deferred loaders declare `__napiBindingTarget` at module
+    // level and go on reporting it, while the CommonJS entries hand back this
+    // very object as `module.exports`, so there the value is absent.
+    return target
+  }
+  try {
+    // [[Define]], not [[Set]]: an ordinary assignment walks the prototype
+    // chain, so an inherited accessor could swallow the value or throw and
+    // fail an otherwise successful load. The descriptor is what a successful
+    // assignment would have produced.
+    Object.defineProperty(exportsObject, '__napiBindingTarget', {
+      configurable: true,
+      enumerable: true,
+      value: target,
+      writable: true,
+    })
+  } catch {
+    // Same rule as the non-extensible skip above: reporting the artifact is
+    // metadata, never a reason to fail an otherwise successful load. An exotic
+    // object (a Proxy whose defineProperty trap refuses) is skipped, not
+    // thrown over.
+  }
+  // The CommonJS loaders assign this return value so `cjs-module-lexer` — and
+  // therefore Node's CJS -> ESM named export detection — can see
+  // `__napiBindingTarget` statically.
+  return target
+}
 
 const __wasi = new __WASI({
   version: 'preview1',
@@ -42,10 +91,40 @@ let __emnapiContext
 
 const __wasiDisposeSymbol = Symbol.for('napi.rs.wasi.dispose')
 const __wasiWorkers = new Set()
+// The thread manager has to be reachable *before* anything that can throw
+// during load or registration. Initialization can fail after the pool has
+// already spawned workers, and the rollback still has to mark their
+// terminations as expected — but `__napiModule` is assigned only when
+// instantiation RETURNS, so on exactly that path it is still undefined. A
+// plugin factory runs while the emnapi module is being created, before the
+// wasm is loaded and before any registration function runs, and its context
+// carries the very same manager instance.
+let __wasiThreadManager
+
+function __captureWasiThreadManager(context) {
+  if (context && context.PThread) {
+    __wasiThreadManager = context.PThread
+  }
+  return {}
+}
+
+function __getWasiThreadManager() {
+  const manager =
+    __wasiThreadManager !== undefined
+      ? __wasiThreadManager
+      : __napiModule
+        ? __napiModule.PThread
+        : undefined
+  if (manager && typeof manager.terminateWorker === 'function') {
+    return manager
+  }
+  return undefined
+}
 let __napiInstance
 let __emnapiContextDestroyed = false
 let __emnapiContextDestroyPromise
 let __emnapiWasmEnvCleanupPrepared = false
+let __emnapiWasmEnvCleanupPreparing = false
 let __emnapiWasmEnvCleanupRan = false
 let __emnapiWasmEnvCleanupDrained = false
 let __emnapiWasmEnvCleanupDrainPromise
@@ -119,13 +198,58 @@ function __attachCleanupErrors(error, cleanupErrors) {
   return aggregate
 }
 
+function __wrapEmnapiContextDestroyForSettlement(
+  context,
+  prepareEnvCleanup,
+  isPreparingEnvCleanup,
+) {
+  let destroy
+  try {
+    destroy = context.destroy
+  } catch {
+    return context
+  }
+  if (typeof destroy !== 'function') {
+    return context
+  }
+  try {
+    Object.defineProperty(context, 'destroy', {
+      configurable: true,
+      enumerable: false,
+      writable: true,
+      value: function () {
+        // Reentered from a promise hook that fired inside the barrier: the
+        // frame running it destroys as soon as it returns.
+        if (isPreparingEnvCleanup?.()) {
+          return
+        }
+        prepareEnvCleanup?.()
+        return Reflect.apply(destroy, this, arguments)
+      },
+    })
+  } catch {}
+  return context
+}
+
+function __isPreparingWasmEnvCleanup() {
+  return __emnapiWasmEnvCleanupPreparing
+}
+
 function __prepareWasmEnvCleanup() {
-  if (__emnapiWasmEnvCleanupPrepared) {
+  if (__emnapiWasmEnvCleanupPrepared || __emnapiWasmEnvCleanupPreparing) {
     return
   }
   const prepare = __napiInstance?.exports?.napi_prepare_wasm_env_cleanup
   if (typeof prepare === 'function') {
-    prepare()
+    // The addon settles the promises it cancels synchronously, under a
+    // non-reentrant lifecycle mutex: anything a promise hook calls from in
+    // here must not reach this export again.
+    __emnapiWasmEnvCleanupPreparing = true
+    try {
+      prepare()
+    } finally {
+      __emnapiWasmEnvCleanupPreparing = false
+    }
     __emnapiWasmEnvCleanupRan = true
   }
   __emnapiWasmEnvCleanupPrepared = true
@@ -318,13 +442,80 @@ function __destroyEmnapiContext() {
   return destroyPromise
 }
 
+/**
+ * Holds the event loop open until `work` settles.
+ *
+ * Nothing else can: the pool workers are deliberately unreferenced so an idle
+ * binding cannot keep a process alive, and referencing them again for the
+ * termination does not hold either — emnapi unreferences a worker the moment it
+ * reports `async-thread-ready`, which for a worker that was still starting
+ * lands *after* the termination began. Without a handle of its own, an
+ * `await dispose()` with nothing else pending exits the process with its
+ * promise unsettled, and everything after the `await` is skipped.
+ *
+ * The timer is cleared as soon as the work settles, so this never outlives the
+ * disposal that asked for it.
+ */
+function __keepEventLoopAliveUntil(work) {
+  const setTimer = globalThis.setInterval
+  const clearTimer = globalThis.clearInterval
+  if (typeof setTimer !== 'function' || typeof clearTimer !== 'function') {
+    return work
+  }
+  let timer
+  try {
+    timer = setTimer(function () {}, 50)
+  } catch {
+    return work
+  }
+  const release = function () {
+    try {
+      clearTimer(timer)
+    } catch {}
+  }
+  return work.then(
+    (value) => {
+      release()
+      return value
+    },
+    (error) => {
+      release()
+      throw error
+    },
+  )
+}
+
+/**
+ * `@emnapi/wasi-threads` counts a worker exit as expected only when its own
+ * thread manager performed the termination. A bare `worker.terminate()` reaches
+ * the manager's `exit` listener instead, which reports
+ * `worker (tid = N) sent an error! ... stopped with exit code 1` and rethrows
+ * inside the emit — aborting the `once('exit')` that backs the terminate
+ * promise, so disposal never settles and the process dies with an uncaught
+ * exception. Mark the termination through the manager first.
+ *
+ * The manager comes from `__getWasiThreadManager`, not from `__napiModule`:
+ * the initialization rollback runs on the one path where instantiation never
+ * returned, so `__napiModule` is still undefined there while the workers it
+ * spawned are already registered and loaded.
+ *
+ * Not `terminateAllThreads()`: that one recreates the pool it just shut down.
+ */
 function __terminateWasiWorkers() {
   const cleanupErrors = []
   const pending = []
+  const threadManager = __getWasiThreadManager()
 
   for (const worker of __wasiWorkers) {
     let result
     try {
+      if (threadManager) {
+        threadManager.terminateWorker(worker)
+        // `terminateWorker` leaves behind a reporter that logs every message
+        // still queued on the port, which Node flushes on exit. Nothing is
+        // listening for those any more.
+        worker.onmessage = undefined
+      }
       result = worker.terminate()
     } catch (error) {
       cleanupErrors.push(error)
@@ -354,7 +545,9 @@ function __terminateWasiWorkers() {
       )
     }
   }
-  return pending.length > 0 ? Promise.all(pending).then(finish) : finish()
+  return pending.length > 0
+    ? __keepEventLoopAliveUntil(Promise.all(pending)).then(finish)
+    : finish()
 }
 
 function __finishWasiDisposal() {
@@ -555,7 +748,11 @@ let __wasiModule
 let __napiModule
 
 try {
-  __emnapiContext = __emnapiCreateContext({ autoDestroy: false })
+  __emnapiContext = __wrapEmnapiContextDestroyForSettlement(
+    __emnapiCreateContext({ autoDestroy: false }),
+    __prepareWasmEnvCleanup,
+    __isPreparingWasmEnvCleanup,
+  )
   __emnapiContext.suppressDestroy()
   
   ;({
@@ -566,7 +763,7 @@ try {
     context: __emnapiContext,
     asyncWorkPoolSize: __asyncWorkPoolSize,
     reuseWorker: false,
-    plugins: [__emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
+    plugins: [__captureWasiThreadManager, __emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
     wasi: __wasi,
     onCreateWorker() {
       const worker = new Worker(new URL('./wasi-worker-browser.mjs', import.meta.url), {
@@ -596,6 +793,12 @@ try {
     },
   }))
   __publishWasiDispose(__napiModule.exports)
+  // The default export hands out this object; a named module export does not
+  // travel with it, so carry the marker on the binding itself too. After the
+  // host install, which hands the same object to addon-provided registration
+  // functions that may put anything on it, and inside this `try`, so a claimed
+  // name fails the load through the rollback below rather than past it.
+  __napiStampBindingTarget(__napiModule.exports, __napiBindingTarget)
 } catch (error) {
   const cleanupErrors = await __rollbackWasiInitialization()
   throw __attachCleanupErrors(error, cleanupErrors)

napi/transform/transform.wasi.cjs

@@ -2,6 +2,56 @@
 /* eslint-disable */
 /* auto-generated by NAPI-RS */
 
+const __napiBindingTarget = 'wasm32-wasi'
+function __napiStampBindingTarget(exportsObject, target) {
+  if (
+    Object.prototype.hasOwnProperty.call(exportsObject, '__napiBindingTarget')
+  ) {
+    if (exportsObject.__napiBindingTarget === target) {
+      // Already ours: the root entry aliases the object it loaded, so a WASI
+      // fallback candidate — or a `NAPI_RS_NATIVE_LIBRARY_PATH` override that
+      // is a generated loader — arrives already stamped with this same value.
+      return target
+    }
+    const error = new Error(
+      '`__napiBindingTarget` is reserved by the generated binding loader, but the loaded binding already exports it. Rename the export, e.g. #[napi(js_name = "...")].',
+    )
+    error.code = 'ERR_NAPI_BINDING_TARGET_CONFLICT'
+    throw error
+  }
+  if (!Object.isExtensible(exportsObject)) {
+    // A `#[napi(module_exports)]` hook may seal or freeze this object
+    // (`Object::seal` / `Object::freeze`). Reporting the artifact is metadata,
+    // never a reason to fail an otherwise successful load, so the stamp is
+    // skipped. What a consumer still sees then follows the entry point: the
+    // browser and deferred loaders declare `__napiBindingTarget` at module
+    // level and go on reporting it, while the CommonJS entries hand back this
+    // very object as `module.exports`, so there the value is absent.
+    return target
+  }
+  try {
+    // [[Define]], not [[Set]]: an ordinary assignment walks the prototype
+    // chain, so an inherited accessor could swallow the value or throw and
+    // fail an otherwise successful load. The descriptor is what a successful
+    // assignment would have produced.
+    Object.defineProperty(exportsObject, '__napiBindingTarget', {
+      configurable: true,
+      enumerable: true,
+      value: target,
+      writable: true,
+    })
+  } catch {
+    // Same rule as the non-extensible skip above: reporting the artifact is
+    // metadata, never a reason to fail an otherwise successful load. An exotic
+    // object (a Proxy whose defineProperty trap refuses) is skipped, not
+    // thrown over.
+  }
+  // The CommonJS loaders assign this return value so `cjs-module-lexer` — and
+  // therefore Node's CJS -> ESM named export detection — can see
+  // `__napiBindingTarget` statically.
+  return target
+}
+
 const __nodeFs = require('node:fs')
 const __nodePath = require('node:path')
 const { WASI: __nodeWASI } = require('node:wasi')
@@ -149,10 +199,40 @@ let __emnapiContext
 
 const __wasiDisposeSymbol = Symbol.for('napi.rs.wasi.dispose')
 const __wasiWorkers = new Set()
+// The thread manager has to be reachable *before* anything that can throw
+// during load or registration. Initialization can fail after the pool has
+// already spawned workers, and the rollback still has to mark their
+// terminations as expected — but `__napiModule` is assigned only when
+// instantiation RETURNS, so on exactly that path it is still undefined. A
+// plugin factory runs while the emnapi module is being created, before the
+// wasm is loaded and before any registration function runs, and its context
+// carries the very same manager instance.
+let __wasiThreadManager
+
+function __captureWasiThreadManager(context) {
+  if (context && context.PThread) {
+    __wasiThreadManager = context.PThread
+  }
+  return {}
+}
+
+function __getWasiThreadManager() {
+  const manager =
+    __wasiThreadManager !== undefined
+      ? __wasiThreadManager
+      : __napiModule
+        ? __napiModule.PThread
+        : undefined
+  if (manager && typeof manager.terminateWorker === 'function') {
+    return manager
+  }
+  return undefined
+}
 let __napiInstance
 let __emnapiContextDestroyed = false
 let __emnapiContextDestroyPromise
 let __emnapiWasmEnvCleanupPrepared = false
+let __emnapiWasmEnvCleanupPreparing = false
 let __emnapiWasmEnvCleanupRan = false
 let __emnapiWasmEnvCleanupDrained = false
 let __emnapiWasmEnvCleanupDrainPromise
@@ -226,13 +306,58 @@ function __attachCleanupErrors(error, cleanupErrors) {
   return aggregate
 }
 
+function __wrapEmnapiContextDestroyForSettlement(
+  context,
+  prepareEnvCleanup,
+  isPreparingEnvCleanup,
+) {
+  let destroy
+  try {
+    destroy = context.destroy
+  } catch {
+    return context
+  }
+  if (typeof destroy !== 'function') {
+    return context
+  }
+  try {
+    Object.defineProperty(context, 'destroy', {
+      configurable: true,
+      enumerable: false,
+      writable: true,
+      value: function () {
+        // Reentered from a promise hook that fired inside the barrier: the
+        // frame running it destroys as soon as it returns.
+        if (isPreparingEnvCleanup?.()) {
+          return
+        }
+        prepareEnvCleanup?.()
+        return Reflect.apply(destroy, this, arguments)
+      },
+    })
+  } catch {}
+  return context
+}
+
+function __isPreparingWasmEnvCleanup() {
+  return __emnapiWasmEnvCleanupPreparing
+}
+
 function __prepareWasmEnvCleanup() {
-  if (__emnapiWasmEnvCleanupPrepared) {
+  if (__emnapiWasmEnvCleanupPrepared || __emnapiWasmEnvCleanupPreparing) {
     return
   }
   const prepare = __napiInstance?.exports?.napi_prepare_wasm_env_cleanup
   if (typeof prepare === 'function') {
-    prepare()
+    // The addon settles the promises it cancels synchronously, under a
+    // non-reentrant lifecycle mutex: anything a promise hook calls from in
+    // here must not reach this export again.
+    __emnapiWasmEnvCleanupPreparing = true
+    try {
+      prepare()
+    } finally {
+      __emnapiWasmEnvCleanupPreparing = false
+    }
     __emnapiWasmEnvCleanupRan = true
   }
   __emnapiWasmEnvCleanupPrepared = true
@@ -425,13 +550,80 @@ function __destroyEmnapiContext() {
   return destroyPromise
 }
 
+/**
+ * Holds the event loop open until `work` settles.
+ *
+ * Nothing else can: the pool workers are deliberately unreferenced so an idle
+ * binding cannot keep a process alive, and referencing them again for the
+ * termination does not hold either — emnapi unreferences a worker the moment it
+ * reports `async-thread-ready`, which for a worker that was still starting
+ * lands *after* the termination began. Without a handle of its own, an
+ * `await dispose()` with nothing else pending exits the process with its
+ * promise unsettled, and everything after the `await` is skipped.
+ *
+ * The timer is cleared as soon as the work settles, so this never outlives the
+ * disposal that asked for it.
+ */
+function __keepEventLoopAliveUntil(work) {
+  const setTimer = globalThis.setInterval
+  const clearTimer = globalThis.clearInterval
+  if (typeof setTimer !== 'function' || typeof clearTimer !== 'function') {
+    return work
+  }
+  let timer
+  try {
+    timer = setTimer(function () {}, 50)
+  } catch {
+    return work
+  }
+  const release = function () {
+    try {
+      clearTimer(timer)
+    } catch {}
+  }
+  return work.then(
+    (value) => {
+      release()
+      return value
+    },
+    (error) => {
+      release()
+      throw error
+    },
+  )
+}
+
+/**
+ * `@emnapi/wasi-threads` counts a worker exit as expected only when its own
+ * thread manager performed the termination. A bare `worker.terminate()` reaches
+ * the manager's `exit` listener instead, which reports
+ * `worker (tid = N) sent an error! ... stopped with exit code 1` and rethrows
+ * inside the emit — aborting the `once('exit')` that backs the terminate
+ * promise, so disposal never settles and the process dies with an uncaught
+ * exception. Mark the termination through the manager first.
+ *
+ * The manager comes from `__getWasiThreadManager`, not from `__napiModule`:
+ * the initialization rollback runs on the one path where instantiation never
+ * returned, so `__napiModule` is still undefined there while the workers it
+ * spawned are already registered and loaded.
+ *
+ * Not `terminateAllThreads()`: that one recreates the pool it just shut down.
+ */
 function __terminateWasiWorkers() {
   const cleanupErrors = []
   const pending = []
+  const threadManager = __getWasiThreadManager()
 
   for (const worker of __wasiWorkers) {
     let result
     try {
+      if (threadManager) {
+        threadManager.terminateWorker(worker)
+        // `terminateWorker` leaves behind a reporter that logs every message
+        // still queued on the port, which Node flushes on exit. Nothing is
+        // listening for those any more.
+        worker.onmessage = undefined
+      }
       result = worker.terminate()
     } catch (error) {
       cleanupErrors.push(error)
@@ -461,7 +653,9 @@ function __terminateWasiWorkers() {
       )
     }
   }
-  return pending.length > 0 ? Promise.all(pending).then(finish) : finish()
+  return pending.length > 0
+    ? __keepEventLoopAliveUntil(Promise.all(pending)).then(finish)
+    : finish()
 }
 
 function __finishWasiDisposal() {
@@ -831,7 +1025,11 @@ function __captureEmnapiAutoDestroyListener() {
 try {
   const __finishAutoDestroyCapture = __captureEmnapiAutoDestroyListener()
   try {
-    __emnapiContext = __emnapiCreateContext({ autoDestroy: false })
+    __emnapiContext = __wrapEmnapiContextDestroyForSettlement(
+      __emnapiCreateContext({ autoDestroy: false }),
+      __prepareWasmEnvCleanup,
+      __isPreparingWasmEnvCleanup,
+    )
     // emnapi 2.x still registers an unconditional once-listener for
     // beforeExit that auto-destroys the context, and suppressDestroy() only
     // neutralizes its callback without removing it. This loader owns cleanup
@@ -859,7 +1057,7 @@ try {
       }
     })(),
     reuseWorker: true,
-    plugins: [__emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
+    plugins: [__captureWasiThreadManager, __emnapiAsyncWorkPlugin, __emnapiTSFNPlugin],
     wasi: __wasi,
     onCreateWorker() {
       const worker = __createWasiWorker(__nodePath.join(__dirname, 'wasi-worker.mjs'))
@@ -889,6 +1087,10 @@ try {
         }
 
         worker.unref()
+        // These stubs stay in place for the worker's whole life, disposal
+        // included: `__keepEventLoopAliveUntil` is what holds the process open
+        // while a termination is pending, precisely because a worker's own
+        // references cannot be relied on for it.
       }
       return worker
     },
@@ -911,6 +1113,22 @@ try {
     },
   }))
   __publishWasiDispose(__napiModule.exports)
+  // The CommonJS tail below aliases `__napiModule.exports`; a named module
+  // export does not travel with it, so carry the marker on the binding itself
+  // too. Three things pin the stamp to exactly this spot:
+  //   - inside this `try`, because the guard throws on a
+  //     `#[napi(module_exports)]` hook that claimed the name, and only the
+  //     catch below tears the environment — context, workers, exit listener —
+  //     back down;
+  //   - after the async runtime host install, which hands this same object to
+  //     addon-provided registration functions that may put anything on it;
+  //   - assigning onto the loader's own `module.exports`, which is still the
+  //     original object here, so an addon accessor with a refusing setter is
+  //     never written through. `cjs-module-lexer` — Node's CJS -> ESM named
+  //     export detection — reads the static `module.exports.<name> =` either
+  //     way, and the later `module.exports = __napiModule.exports` does not
+  //     undo that.
+  module.exports.__napiBindingTarget = __napiStampBindingTarget(__napiModule.exports, __napiBindingTarget)
   __registerWasiExitListener()
 } catch (error) {
   const rollback = {

napi/transform/transform.wasi.d.cts

@@ -1,6 +1,9 @@
 /* auto-generated by NAPI-RS */
 /* eslint-disable */
 
+/** The WASI flavor this loader instantiates. */
+export declare const __napiBindingTarget: 'wasm32-wasi'
+
 export interface Comment {
   type: 'Line' | 'Block'
   value: string

pnpm-lock.yaml

@@ -117,8 +117,8 @@ catalogs:
       specifier: 2.0.0-alpha.3
       version: 2.0.0-alpha.3
     '@napi-rs/cli':
-      specifier: 3.9.1
-      version: 3.9.1
+      specifier: 3.10.1
+      version: 3.10.1
     '@napi-rs/wasm-runtime':
       specifier: 1.2.4
       version: 1.2.4
@@ -161,7 +161,7 @@ importers:
     devDependencies:
       '@napi-rs/cli':
         specifier: 'catalog:'
-        version: 3.9.1(@emnapi/core@1.9.2)(@emnapi/runtime@1.9.2)(@types/node@25.0.2)(emnapi@2.0.0-alpha.3)
+        version: 3.10.1(@emnapi/core@1.9.2)(@emnapi/runtime@1.9.2)(@types/node@25.0.2)(emnapi@2.0.0-alpha.3)
       oxfmt:
         specifier: ^0.67.0
         version: 0.67.0(svelte@5.57.0(@typescript-eslint/types@8.69.0))(vite-plus@0.3.0(@arethetypeswrong/core@0.18.5)(@types/node@25.0.2)(@vitest/browser-playwright@4.1.11)(esbuild@0.28.2)(happy-dom@20.0.11)(publint@0.3.24)(svelte@5.57.0(@typescript-eslint/types@8.69.0))(terser@5.44.1)(tsx@4.23.13)(typescript@6.0.3)(vite@8.3.0(@types/node@25.0.2)(esbuild@0.28.2)(terser@5.44.1)(tsx@4.23.13)))
@@ -192,7 +192,7 @@ importers:
         version: 0.18.5
       '@napi-rs/cli':
         specifier: 'catalog:'
-        version: 3.9.1(@emnapi/core@1.9.2)(@emnapi/runtime@1.9.2)(@types/node@24.1.0)(emnapi@2.0.0-alpha.3)
+        version: 3.10.1(@emnapi/core@1.9.2)(@emnapi/runtime@1.9.2)(@types/node@24.1.0)(emnapi@2.0.0-alpha.3)
       '@oxapps/shared':
         specifier: workspace:*
         version: link:../shared
@@ -240,7 +240,7 @@ importers:
         version: 8.0.0
       '@napi-rs/cli':
         specifier: 'catalog:'
-        version: 3.9.1(@emnapi/core@1.9.2)(@emnapi/runtime@1.9.2)(@types/node@24.1.0)(emnapi@2.0.0-alpha.3)
+        version: 3.10.1(@emnapi/core@1.9.2)(@emnapi/runtime@1.9.2)(@types/node@24.1.0)(emnapi@2.0.0-alpha.3)
       '@oxapps/shared':
         specifier: workspace:*
         version: link:../shared
@@ -354,7 +354,7 @@ importers:
         version: 2.0.0-alpha.3
       '@napi-rs/cli':
         specifier: 'catalog:'
-        version: 3.9.1(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)(@types/node@24.1.0)(emnapi@2.0.0-alpha.3)
+        version: 3.10.1(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)(@types/node@24.1.0)(emnapi@2.0.0-alpha.3)
       '@types/node':
         specifier: 'catalog:'
         version: 24.1.0
@@ -382,7 +382,7 @@ importers:
         version: 2.0.0-alpha.3
       '@napi-rs/cli':
         specifier: 'catalog:'
-        version: 3.9.1(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)(@types/node@24.1.0)(emnapi@2.0.0-alpha.3)
+        version: 3.10.1(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)(@types/node@24.1.0)(emnapi@2.0.0-alpha.3)
       '@napi-rs/wasm-runtime':
         specifier: 'catalog:'
         version: 1.2.4(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)
@@ -428,7 +428,7 @@ importers:
         version: 2.0.0-alpha.3
       '@napi-rs/cli':
         specifier: 'catalog:'
-        version: 3.9.1(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)(@types/node@25.0.2)(emnapi@2.0.0-alpha.3)
+        version: 3.10.1(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)(@types/node@25.0.2)(emnapi@2.0.0-alpha.3)
       publint:
         specifier: 'catalog:'
         version: 0.3.24
@@ -443,7 +443,7 @@ importers:
         version: 2.0.0-alpha.3
       '@napi-rs/cli':
         specifier: 'catalog:'
-        version: 3.9.1(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)(@types/node@24.1.0)(emnapi@2.0.0-alpha.3)
+        version: 3.10.1(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)(@types/node@24.1.0)(emnapi@2.0.0-alpha.3)
       '@types/node':
         specifier: 'catalog:'
         version: 24.1.0
@@ -464,7 +464,7 @@ importers:
         version: 2.0.0-alpha.3
       '@napi-rs/cli':
         specifier: 'catalog:'
-        version: 3.9.1(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)(@types/node@24.1.0)(emnapi@2.0.0-alpha.3)
+        version: 3.10.1(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)(@types/node@24.1.0)(emnapi@2.0.0-alpha.3)
       '@types/node':
         specifier: 'catalog:'
         version: 24.1.0
@@ -485,7 +485,7 @@ importers:
         version: 2.0.0-alpha.3
       '@napi-rs/cli':
         specifier: 'catalog:'
-        version: 3.9.1(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)(@types/node@24.1.0)(emnapi@2.0.0-alpha.3)
+        version: 3.10.1(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)(@types/node@24.1.0)(emnapi@2.0.0-alpha.3)
       '@types/node':
         specifier: 'catalog:'
         version: 24.1.0
@@ -553,7 +553,7 @@ importers:
     devDependencies:
       '@napi-rs/cli':
         specifier: 'catalog:'
-        version: 3.9.1(@emnapi/core@1.9.2)(@emnapi/runtime@1.9.2)(@types/node@25.0.2)(emnapi@2.0.0-alpha.3)
+        version: 3.10.1(@emnapi/core@1.9.2)(@emnapi/runtime@1.9.2)(@types/node@25.0.2)(emnapi@2.0.0-alpha.3)
 
   tasks/compat_data:
     devDependencies:
@@ -1480,8 +1480,8 @@ packages:
     resolution: {integrity: sha512-Z7C/xXCiGWsg0KuKsHTKJxbWhpI3Vs5GwLfOean7MGyVFGqdRgBbAjOCh6u4bbjPc/8MJ2pZmK/0DLdCbivLDA==}
     engines: {node: '>=8'}
 
-  '@napi-rs/cli@3.9.1':
-    resolution: {integrity: sha512-2DYBrM2j4n00L+O7fKAS38q19rVQK2HXz5RxSuJgFyZrd9TrdVQFmHOfqvqqsRIRBTZmqiMqBd/yzn4X1a23DQ==}
+  '@napi-rs/cli@3.10.1':
+    resolution: {integrity: sha512-9w66AHq2U3vIfj7G0UlVUOENbt6M7XHlHxa+rSbxkVhmCXKY2GIvLGLyYfWz8wBMjwC7dJojNInQhhUJU4hJUw==}
     engines: {node: ^20.17.0 || ^22.13.0 || >= 23.5.0}
     hasBin: true
     peerDependencies:
@@ -4936,6 +4936,10 @@ packages:
     resolution: {integrity: sha512-4a+OsYv9UktOJKE+l1A4OufDgdRF9PifWj+tJnHURo/P+WOxpG4GzUFL9qCalmWauao6ogiG+QvnCovwPoyAWA==}
     engines: {node: '>=12.20.0'}
 
+  obug@3.0.0:
+    resolution: {integrity: sha512-5vvB5+W7ePv+p3uqxi+RcW1XAzLW0/hxt3/4X4Lc4qHudzOhmBiBwOY6DRob4WnanAEGvNcLjF+KNOufrUoEQw==}
+    engines: {node: '>=12.20.0'}
+
   on-finished@2.4.1:
     resolution: {integrity: sha512-oVlzkg3ENAhCk2zdv7IJwd/QUD4z2RxRwpkcGY8psCVcCYZNq4wYnVWALHM+brtuJjePWiYF/ClmuDr8Ch5+kg==}
     engines: {node: '>= 0.8'}
@@ -6722,7 +6726,7 @@ snapshots:
 
   '@lukeed/csprng@1.1.0': {}
 
-  '@napi-rs/cli@3.9.1(@emnapi/core@1.9.2)(@emnapi/runtime@1.9.2)(@types/node@24.1.0)(emnapi@2.0.0-alpha.3)':
+  '@napi-rs/cli@3.10.1(@emnapi/core@1.9.2)(@emnapi/runtime@1.9.2)(@types/node@24.1.0)(emnapi@2.0.0-alpha.3)':
     dependencies:
       '@inquirer/prompts': 8.5.2(@types/node@24.1.0)
       '@napi-rs/cross-toolchain': 1.0.3(@emnapi/core@1.9.2)(@emnapi/runtime@1.9.2)
@@ -6732,7 +6736,7 @@ snapshots:
       colorette: 2.0.20
       es-toolkit: 1.47.0
       js-yaml: 5.4.1
-      obug: 2.1.4
+      obug: 3.0.0
       semver: 7.8.5
       typanion: 3.14.0
       typescript: 6.0.3
@@ -6754,7 +6758,7 @@ snapshots:
       - '@types/node'
       - supports-color
 
-  '@napi-rs/cli@3.9.1(@emnapi/core@1.9.2)(@emnapi/runtime@1.9.2)(@types/node@25.0.2)(emnapi@2.0.0-alpha.3)':
+  '@napi-rs/cli@3.10.1(@emnapi/core@1.9.2)(@emnapi/runtime@1.9.2)(@types/node@25.0.2)(emnapi@2.0.0-alpha.3)':
     dependencies:
       '@inquirer/prompts': 8.5.2(@types/node@25.0.2)
       '@napi-rs/cross-toolchain': 1.0.3(@emnapi/core@1.9.2)(@emnapi/runtime@1.9.2)
@@ -6764,7 +6768,7 @@ snapshots:
       colorette: 2.0.20
       es-toolkit: 1.47.0
       js-yaml: 5.4.1
-      obug: 2.1.4
+      obug: 3.0.0
       semver: 7.8.5
       typanion: 3.14.0
       typescript: 6.0.3
@@ -6786,7 +6790,7 @@ snapshots:
       - '@types/node'
       - supports-color
 
-  '@napi-rs/cli@3.9.1(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)(@types/node@24.1.0)(emnapi@2.0.0-alpha.3)':
+  '@napi-rs/cli@3.10.1(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)(@types/node@24.1.0)(emnapi@2.0.0-alpha.3)':
     dependencies:
       '@inquirer/prompts': 8.5.2(@types/node@24.1.0)
       '@napi-rs/cross-toolchain': 1.0.3(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)
@@ -6796,7 +6800,7 @@ snapshots:
       colorette: 2.0.20
       es-toolkit: 1.47.0
       js-yaml: 5.4.1
-      obug: 2.1.4
+      obug: 3.0.0
       semver: 7.8.5
       typanion: 3.14.0
       typescript: 6.0.3
@@ -6818,7 +6822,7 @@ snapshots:
       - '@types/node'
       - supports-color
 
-  '@napi-rs/cli@3.9.1(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)(@types/node@25.0.2)(emnapi@2.0.0-alpha.3)':
+  '@napi-rs/cli@3.10.1(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)(@types/node@25.0.2)(emnapi@2.0.0-alpha.3)':
     dependencies:
       '@inquirer/prompts': 8.5.2(@types/node@25.0.2)
       '@napi-rs/cross-toolchain': 1.0.3(@emnapi/core@2.0.0-alpha.3)(@emnapi/runtime@2.0.0-alpha.3)
@@ -6828,7 +6832,7 @@ snapshots:
       colorette: 2.0.20
       es-toolkit: 1.47.0
       js-yaml: 5.4.1
-      obug: 2.1.4
+      obug: 3.0.0
       semver: 7.8.5
       typanion: 3.14.0
       typescript: 6.0.3
@@ -9876,6 +9880,8 @@ snapshots:
 
   obug@2.1.4: {}
 
+  obug@3.0.0: {}
+
   on-finished@2.4.1:
     dependencies:
       ee-first: 1.1.1

pnpm-workspace.yaml

@@ -14,7 +14,7 @@ catalog:
   "@emnapi/runtime": 2.0.0-alpha.3
   emnapi: 2.0.0-alpha.3
   "@arethetypeswrong/core": 0.18.5
-  "@napi-rs/cli": 3.9.1
+  "@napi-rs/cli": 3.10.1
   "@napi-rs/wasm-runtime": 1.2.4
   "@types/node": 24.1.0
   cross-env: ^10.1.0

tasks/codegen_conformance/index.d.ts

@@ -1,6 +1,14 @@
 /* auto-generated by NAPI-RS */
 /* eslint-disable */
 
+/**
+ * Which binding artifact the generated loader actually loaded: `'native'` for
+ * a native addon, otherwise the `platformArchABI` of the WASI flavor. Every
+ * flavor napi-rs can build is listed, because `NAPI_RS_NATIVE_LIBRARY_PATH`
+ * can point the loader at a WASI artifact this package does not build itself.
+ */
+export declare const __napiBindingTarget: 'native' | 'wasm32-wasi' | 'wasm32-wasip1'
+
 /**
  * Parse `source_text` with `oxc_parser` and print the AST with `oxc_codegen`, including a source map.
  *

tasks/codegen_conformance/index.js

@@ -7,6 +7,10 @@ const require = createRequire(import.meta.url)
 
 const { readFileSync } = require('fs')
 let nativeBinding = null
+// Which artifact actually loaded. The WASI fallback chain overwrites it with
+// the flavor it resolved; the late native retry below leaves it alone because
+// it only runs while no WASI candidate has been loaded.
+let __napiLoadedBindingTarget = 'native'
 const loadErrors = []
 
 const isMusl = () => {
@@ -65,7 +69,16 @@ const isMuslFromChildProcess = () => {
 function requireNative() {
   if (process.env.NAPI_RS_NATIVE_LIBRARY_PATH) {
     try {
-      return require(process.env.NAPI_RS_NATIVE_LIBRARY_PATH)
+      const overrideBinding = require(process.env.NAPI_RS_NATIVE_LIBRARY_PATH)
+      // The override may be a generated WASI loader, which already reports its
+      // own flavor. Adopt it: `module.exports` aliases this object, so claiming
+      // 'native' would both misreport the artifact and overwrite the loader's
+      // marker through the alias.
+      __napiLoadedBindingTarget =
+        overrideBinding && typeof overrideBinding.__napiBindingTarget === 'string'
+          ? overrideBinding.__napiBindingTarget
+          : 'native'
+      return overrideBinding
     } catch (err) {
       loadErrors.push(err)
     }
@@ -630,6 +643,7 @@ if (!nativeBinding || forceWasi) {
       if (!candidateFailed) {
         wasiBinding = require('./codegen_conformance.wasi.cjs')
         nativeBinding = wasiBinding
+        __napiLoadedBindingTarget = 'wasm32-wasi'
         wasiBindingLoaded = true
       }
     } catch (err) {
@@ -656,6 +670,7 @@ if (!nativeBinding || forceWasi) {
         }
         wasiBinding = require('oxc-codegen-conformance-wasm32-wasi')
         nativeBinding = wasiBinding
+        __napiLoadedBindingTarget = 'wasm32-wasi'
         wasiBindingLoaded = true
       }
     } catch (err) {
@@ -704,3 +719,4 @@ if (!nativeBinding) {
 const { codegen, Severity } = nativeBinding
 export { codegen }
 export { Severity }
+export const __napiBindingTarget = __napiLoadedBindingTarget