fix(react-compiler): preserve warning bailouts (#24935)

Preserve warning-level React Compiler diagnostics instead of wrapping pipeline bailouts in a synthetic fatal error. This keeps expected incompatible-library and Todo bailouts non-fatal so sibling functions can still compile.

Adds regression coverage and refreshes the affected snapshots. Validated with `just ready`.

AI-assisted: Codex was used to investigate, implement, and validate this change.

crates/oxc_react_compiler/src/diagnostics.rs

@@ -122,30 +122,6 @@ pub fn has_critical_errors(diagnostics: &[OxcDiagnostic]) -> bool {
         .any(|d| d.severity == Severity::Error && !ErrorCategory::PreserveManualMemo.matches(d))
 }
 
-/// Format a thrown diagnostic as a string matching the TS
-/// `CompilerError.toString()` output, used for the `data` field of
-/// `CompileUnexpectedThrow` events: `"<Heading>: <reason>. <description>."`.
-/// The reason is the message minus the deterministic prefix added by
-/// [`ErrorCategory::diagnostic`].
-pub fn to_string_for_event(diagnostic: &OxcDiagnostic) -> String {
-    let category = ErrorCategory::of(diagnostic);
-    let heading = match category {
-        Some("IncompatibleLibrary" | "PreserveManualMemo" | "UnsupportedSyntax") => {
-            "Compilation Skipped"
-        }
-        Some(heading @ ("Invariant" | "Todo")) => heading,
-        _ => "Error",
-    };
-    let reason = category
-        .and_then(|c| diagnostic.message.strip_prefix(&format!("[ReactCompiler] {c}: ")))
-        .unwrap_or(&diagnostic.message);
-    let mut buf = format!("{heading}: {reason}");
-    if let Some(help) = &diagnostic.help {
-        buf.push_str(&format!(". {help}."));
-    }
-    buf
-}
-
 /// Owned copy of a diagnostic for the log accumulator, labelling the enclosing
 /// function (`fn_span`) when the diagnostic carries no location of its own.
 #[cold]

crates/oxc_react_compiler/src/react_compiler/entrypoint/pipeline.rs

@@ -10,9 +10,8 @@
 
 use oxc_allocator::GetAllocator;
 use oxc_diagnostics::{Diagnostics, OxcDiagnostic};
-use oxc_span::Span;
 
-use crate::diagnostics::{ErrorCategory, to_string_for_event};
+use crate::diagnostics::ErrorCategory;
 use crate::react_compiler_hir::ReactFunctionType;
 use crate::react_compiler_hir::environment::Environment;
 use crate::react_compiler_hir::environment::OutputMode;
@@ -91,9 +90,6 @@ use crate::options::CompilerOutputMode;
 /// Run the compilation pipeline on a single function.
 ///
 /// On failure, returns the diagnostics of the failed compilation attempt.
-/// An error thrown by a pass (in TS: an exception escaping the pass) that is
-/// not an Invariant additionally surfaces a `CompileUnexpectedThrow`
-/// diagnostic, matching TS `tryCompileFunction`'s catch block.
 #[allow(clippy::too_many_arguments)]
 pub fn compile_fn<'a>(
     ast: &oxc_ast::builder::AstBuilder<'a>,
@@ -103,32 +99,19 @@ pub fn compile_fn<'a>(
     mode: CompilerOutputMode,
     env_config: &EnvironmentConfig,
     context: &mut ProgramContext<'a>,
-    fn_span: Option<Span>,
 ) -> Result<Option<CodegenFunction<'a>>, Diagnostics> {
     match run_pipeline(ast, func, scope, fn_type, mode, env_config, context) {
         Ok(result) => result,
-        Err(thrown) => {
-            if !ErrorCategory::Invariant.matches(&thrown) {
-                let mut diagnostic = OxcDiagnostic::error(format!(
-                    "[ReactCompiler] Unexpected error: {}",
-                    to_string_for_event(&thrown)
-                ));
-                if let Some(span) = fn_span {
-                    diagnostic = diagnostic.with_label(span);
-                }
-                context.diagnostics.push(diagnostic);
-            }
-            Err(Diagnostics::from(thrown))
-        }
+        Err(diagnostic) => Err(Diagnostics::from(diagnostic)),
     }
 }
 
 /// The pass pipeline: creates an Environment, runs BuildHIR (lowering), the
 /// HIR/reactive-scope passes, and codegen.
 ///
-/// `Err(OxcDiagnostic)` is an error thrown by a pass (a TS exception);
+/// `Err(OxcDiagnostic)` is a diagnostic that immediately bails out of a pass.
 /// Invariant and end-of-pipeline accumulated errors return as
-/// `Ok(Err(diagnostics))` since they must not surface `CompileUnexpectedThrow`.
+/// `Ok(Err(diagnostics))`.
 #[allow(clippy::too_many_arguments)]
 fn run_pipeline<'a>(
     ast: &oxc_ast::builder::AstBuilder<'a>,

crates/oxc_react_compiler/src/react_compiler/entrypoint/program.rs

@@ -1056,8 +1056,7 @@ fn try_compile_function<'a>(
     env_config: &EnvironmentConfig,
     context: &mut ProgramContext<'a>,
 ) -> Result<Option<CodegenFunction<'a>>, Diagnostics> {
-    // Check for suppressions that affect this function. Suppression errors are
-    // returned (not thrown), so they do NOT trigger CompileUnexpectedThrow.
+    // Check for suppressions that affect this function before entering the pipeline.
     if let (Some(start), Some(end)) = (source.fn_start, source.fn_end) {
         let affecting = filter_suppressions_that_affect_function(&context.suppressions, start, end);
         if !affecting.is_empty() {
@@ -1075,7 +1074,6 @@ fn try_compile_function<'a>(
         output_mode,
         env_config,
         context,
-        source.fn_ast_span,
     )
 }
 

crates/oxc_react_compiler/tests/snapshots/error.dont-hoist-inline-reference.snap

@@ -4,7 +4,6 @@ input_file: crates/oxc_react_compiler/fixtures/error.dont-hoist-inline-reference
 ---
 Diagnostics:
 
-OxcDiagnostic { inner: OxcDiagnosticInner { message: "[ReactCompiler] Unexpected error: Todo: [hoisting] EnterSSA: Expected identifier to be defined before being used. Identifier x$1 is undefined.", labels: One([LabeledSpan { label: None, span: SourceSpan { offset: SourceOffset(41), length: 62 }, primary: false }]), help: None, note: None, severity: Error, code: OxcCode { scope: None, number: None }, url: None } }
 OxcDiagnostic { inner: OxcDiagnosticInner { message: "[ReactCompiler] Todo: [hoisting] EnterSSA: Expected identifier to be defined before being used", labels: One([LabeledSpan { label: None, span: SourceSpan { offset: SourceOffset(67), length: 22 }, primary: false }]), help: Some("Identifier x$1 is undefined"), note: None, severity: Warning, code: OxcCode { scope: None, number: None }, url: None } }
 
 No changes.

crates/oxc_react_compiler/tests/snapshots/error.invalid-known-incompatible-function.snap

@@ -4,7 +4,6 @@ input_file: crates/oxc_react_compiler/fixtures/error.invalid-known-incompatible-
 ---
 Diagnostics:
 
-OxcDiagnostic { inner: OxcDiagnosticInner { message: "[ReactCompiler] Unexpected error: Compilation Skipped: Use of incompatible library. This API returns functions which cannot be memoized without leading to stale UI. To prevent this, by default React Compiler will skip memoizing this component/hook. However, you may see issues if values from this API are passed to other components/hooks that are memoized.", labels: One([LabeledSpan { label: None, span: SourceSpan { offset: SourceOffset(71), length: 87 }, primary: false }]), help: None, note: None, severity: Error, code: OxcCode { scope: None, number: None }, url: None } }
 OxcDiagnostic { inner: OxcDiagnosticInner { message: "[ReactCompiler] IncompatibleLibrary: Use of incompatible library", labels: One([LabeledSpan { label: Some("useKnownIncompatible is known to be incompatible"), span: SourceSpan { offset: SourceOffset(109), length: 17 }, primary: false }]), help: Some("This API returns functions which cannot be memoized without leading to stale UI. To prevent this, by default React Compiler will skip memoizing this component/hook. However, you may see issues if values from this API are passed to other components/hooks that are memoized"), note: None, severity: Warning, code: OxcCode { scope: None, number: None }, url: None } }
 
 No changes.

crates/oxc_react_compiler/tests/snapshots/error.invalid-known-incompatible-hook-return-property.snap

@@ -4,7 +4,6 @@ input_file: crates/oxc_react_compiler/fixtures/error.invalid-known-incompatible-
 ---
 Diagnostics:
 
-OxcDiagnostic { inner: OxcDiagnosticInner { message: "[ReactCompiler] Unexpected error: Compilation Skipped: Use of incompatible library. This API returns functions which cannot be memoized without leading to stale UI. To prevent this, by default React Compiler will skip memoizing this component/hook. However, you may see issues if values from this API are passed to other components/hooks that are memoized.", labels: One([LabeledSpan { label: None, span: SourceSpan { offset: SourceOffset(82), length: 119 }, primary: false }]), help: None, note: None, severity: Error, code: OxcCode { scope: None, number: None }, url: None } }
 OxcDiagnostic { inner: OxcDiagnosticInner { message: "[ReactCompiler] IncompatibleLibrary: Use of incompatible library", labels: One([LabeledSpan { label: Some("useKnownIncompatibleIndirect returns an incompatible() function that is known incompatible"), span: SourceSpan { offset: SourceOffset(177), length: 12 }, primary: false }]), help: Some("This API returns functions which cannot be memoized without leading to stale UI. To prevent this, by default React Compiler will skip memoizing this component/hook. However, you may see issues if values from this API are passed to other components/hooks that are memoized"), note: None, severity: Warning, code: OxcCode { scope: None, number: None }, url: None } }
 
 No changes.

crates/oxc_react_compiler/tests/snapshots/error.invalid-known-incompatible-hook.snap

@@ -4,7 +4,6 @@ input_file: crates/oxc_react_compiler/fixtures/error.invalid-known-incompatible-
 ---
 Diagnostics:
 
-OxcDiagnostic { inner: OxcDiagnosticInner { message: "[ReactCompiler] Unexpected error: Compilation Skipped: Use of incompatible library. This API returns functions which cannot be memoized without leading to stale UI. To prevent this, by default React Compiler will skip memoizing this component/hook. However, you may see issues if values from this API are passed to other components/hooks that are memoized.", labels: One([LabeledSpan { label: None, span: SourceSpan { offset: SourceOffset(74), length: 90 }, primary: false }]), help: None, note: None, severity: Error, code: OxcCode { scope: None, number: None }, url: None } }
 OxcDiagnostic { inner: OxcDiagnosticInner { message: "[ReactCompiler] IncompatibleLibrary: Use of incompatible library", labels: One([LabeledSpan { label: Some("useKnownIncompatible is known to be incompatible"), span: SourceSpan { offset: SourceOffset(112), length: 20 }, primary: false }]), help: Some("This API returns functions which cannot be memoized without leading to stale UI. To prevent this, by default React Compiler will skip memoizing this component/hook. However, you may see issues if values from this API are passed to other components/hooks that are memoized"), note: None, severity: Warning, code: OxcCode { scope: None, number: None }, url: None } }
 
 No changes.

crates/oxc_react_compiler/tests/snapshots/error.todo-functiondecl-hoisting.snap

@@ -4,7 +4,6 @@ input_file: crates/oxc_react_compiler/fixtures/error.todo-functiondecl-hoisting.
 ---
 Diagnostics:
 
-OxcDiagnostic { inner: OxcDiagnosticInner { message: "[ReactCompiler] Unexpected error: Todo: [PruneHoistedContexts] Rewrite hoisted function references", labels: One([LabeledSpan { label: None, span: SourceSpan { offset: SourceOffset(330), length: 164 }, primary: false }]), help: None, note: None, severity: Error, code: OxcCode { scope: None, number: None }, url: None } }
 OxcDiagnostic { inner: OxcDiagnosticInner { message: "[ReactCompiler] Todo: [PruneHoistedContexts] Rewrite hoisted function references", labels: One([LabeledSpan { label: None, span: SourceSpan { offset: SourceOffset(371), length: 3 }, primary: false }]), help: None, note: None, severity: Warning, code: OxcCode { scope: None, number: None }, url: None } }
 
 No changes.

crates/oxc_react_compiler/tests/snapshots/error.todo-hook-call-spreads-mutable-iterator.snap

@@ -4,7 +4,6 @@ input_file: crates/oxc_react_compiler/fixtures/error.todo-hook-call-spreads-muta
 ---
 Diagnostics:
 
-OxcDiagnostic { inner: OxcDiagnosticInner { message: "[ReactCompiler] Unexpected error: Todo: Support spread syntax for hook arguments", labels: One([LabeledSpan { label: None, span: SourceSpan { offset: SourceOffset(45), length: 120 }, primary: false }]), help: None, note: None, severity: Error, code: OxcCode { scope: None, number: None }, url: None } }
 OxcDiagnostic { inner: OxcDiagnosticInner { message: "[ReactCompiler] Todo: Support spread syntax for hook arguments", labels: One([LabeledSpan { label: None, span: SourceSpan { offset: SourceOffset(147), length: 14 }, primary: false }]), help: None, note: None, severity: Warning, code: OxcCode { scope: None, number: None }, url: None } }
 
 No changes.

crates/oxc_react_compiler/tests/snapshots/error.todo-rust-as-expression-assignment-target.snap

@@ -4,7 +4,6 @@ input_file: crates/oxc_react_compiler/fixtures/error.todo-rust-as-expression-ass
 ---
 Diagnostics:
 
-OxcDiagnostic { inner: OxcDiagnosticInner { message: "[ReactCompiler] Unexpected error: Todo: [FindContextIdentifiers] Cannot handle Object destructuring assignment target TSAsExpression", labels: One([LabeledSpan { label: None, span: SourceSpan { offset: SourceOffset(0), length: 137 }, primary: false }]), help: None, note: None, severity: Error, code: OxcCode { scope: None, number: None }, url: None } }
 OxcDiagnostic { inner: OxcDiagnosticInner { message: "[ReactCompiler] Todo: [FindContextIdentifiers] Cannot handle Object destructuring assignment target TSAsExpression", labels: One([LabeledSpan { label: None, span: SourceSpan { offset: SourceOffset(52), length: 32 }, primary: false }]), help: None, note: None, severity: Warning, code: OxcCode { scope: None, number: None }, url: None } }
 
 No changes.

crates/oxc_react_compiler/tests/snapshots/error.todo-valid-functiondecl-hoisting.snap

@@ -4,7 +4,6 @@ input_file: crates/oxc_react_compiler/fixtures/error.todo-valid-functiondecl-hoi
 ---
 Diagnostics:
 
-OxcDiagnostic { inner: OxcDiagnosticInner { message: "[ReactCompiler] Unexpected error: Todo: [PruneHoistedContexts] Rewrite hoisted function references", labels: One([LabeledSpan { label: None, span: SourceSpan { offset: SourceOffset(307), length: 180 }, primary: false }]), help: None, note: None, severity: Error, code: OxcCode { scope: None, number: None }, url: None } }
 OxcDiagnostic { inner: OxcDiagnosticInner { message: "[ReactCompiler] Todo: [PruneHoistedContexts] Rewrite hoisted function references", labels: One([LabeledSpan { label: None, span: SourceSpan { offset: SourceOffset(369), length: 3 }, primary: false }]), help: None, note: None, severity: Warning, code: OxcCode { scope: None, number: None }, url: None } }
 
 No changes.

crates/oxc_react_compiler/tests/transform.rs

@@ -447,6 +447,56 @@ fn diagnostics_preserve_compiler_severity() {
     );
 }
 
+/// A warning-level function bail-out must not be promoted to a fatal error:
+/// sibling functions should still compile and downstream transforms should run.
+#[test]
+fn incompatible_library_bailout_remains_a_warning() {
+    let source = "\
+import { useReactTable } from '@tanstack/react-table';\n\
+function Table() {\n\
+  const table = useReactTable({});\n\
+  return <div>{table}</div>;\n\
+}\n\
+export function Component(props: { text: string }) {\n\
+  return <span>{props.text}</span>;\n\
+}\n";
+
+    let allocator = Allocator::default();
+    let (program, result) = transform_source(source, SourceType::tsx(), &allocator, options());
+
+    assert!(result.changed, "the unaffected component should compile");
+    assert!(
+        result.diagnostics.has_warnings(),
+        "the incompatible library should report a warning: {:?}",
+        result.diagnostics
+    );
+    assert!(
+        !result.diagnostics.has_errors(),
+        "a warning-level function bail-out must not become fatal: {:?}",
+        result.diagnostics
+    );
+    assert_eq!(result.diagnostics.len(), 1);
+    assert!(
+        result.diagnostics[0].message.contains("[ReactCompiler] IncompatibleLibrary"),
+        "expected the original compiler diagnostic: {:?}",
+        result.diagnostics
+    );
+    assert!(
+        result
+            .diagnostics
+            .iter()
+            .all(|diagnostic| !diagnostic.message.contains("Unexpected error")),
+        "the bail-out must not create a synthetic error: {:?}",
+        result.diagnostics
+    );
+
+    let output = Codegen::new().build(&program).code;
+    assert!(
+        output.contains("react/compiler-runtime"),
+        "expected the unaffected component to be transformed:\n{output}"
+    );
+}
+
 /// The transform only rewrites the compiled functions, so top-level comments
 /// survive; comments inside a compiled function are pruned because their anchor no
 /// longer resolves to a statement (see `prune_inner_comments`).