refactor(linter): compute lintable extensions at compile time (#10090)

Previously, we were wasting some time creating a `Vec` at runtime with the lintable extensions, which is all of the JS/TS extensions plus other frameworks extensions like `.vue`. Now, we precompute this as a static string slice at compile time. This also ensures that we are using the same extensions list between `oxlint` and the language server too. Theoretically this is a very minor perf win possibly?

.vscode/extensions.json

@@ -5,6 +5,6 @@
     "tamasfe.even-better-toml", // toml syntax
     "nefrob.vscode-just-syntax", // justfile syntax & task runner
     "tekumara.typos-vscode", // spell checker
-    "EditorConfig.EditorConfig", // editorconfig
+    "EditorConfig.EditorConfig" // editorconfig
   ]
 }

Cargo.lock

@@ -319,6 +319,12 @@ dependencies = [
  "windows-sys 0.59.0",
 ]
 
+[[package]]
+name = "constcat"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5ffb5df6dd5dadb422897e8132f415d7a054e3cd757e5070b663f75bea1840fb"
+
 [[package]]
 name = "convert_case"
 version = "0.8.0"
@@ -1809,7 +1815,6 @@ dependencies = [
  "oxc_linter",
  "oxc_parser",
  "oxc_semantic",
- "oxc_span",
  "papaya",
  "rustc-hash",
  "serde",
@@ -1823,6 +1828,7 @@ name = "oxc_linter"
 version = "0.16.3"
 dependencies = [
  "bitflags 2.9.0",
+ "constcat",
  "convert_case",
  "cow-utils",
  "fast-glob",

Cargo.toml

@@ -168,6 +168,7 @@ bpaf = "0.9.16"
 bumpalo = "=3.17.0"
 compact_str = "0.9.0"
 console = "0.15.10"
+constcat = "0.6.0"
 convert_case = "0.8.0"
 cow-utils = "0.1.3"
 criterion2 = { version = "3.0.0", default-features = false }

apps/oxlint/src/lint.rs

@@ -10,16 +10,15 @@ use ignore::{gitignore::Gitignore, overrides::OverrideBuilder};
 use oxc_diagnostics::{DiagnosticService, GraphicalReportHandler, OxcDiagnostic};
 use oxc_linter::{
     AllowWarnDeny, ConfigStore, ConfigStoreBuilder, InvalidFilterKind, LintFilter, LintOptions,
-    LintService, LintServiceOptions, Linter, Oxlintrc, loader::LINT_PARTIAL_LOADER_EXT,
+    LintService, LintServiceOptions, Linter, Oxlintrc,
 };
-use oxc_span::VALID_EXTENSIONS;
 use rustc_hash::{FxHashMap, FxHashSet};
 use serde_json::Value;
 
 use crate::{
     cli::{CliRunResult, LintCommand, MiscOptions, ReportUnusedDirectives, Runner, WarningOptions},
     output_formatter::{LintCommandInfo, OutputFormatter},
-    walk::{Extensions, Walk},
+    walk::Walk,
 };
 
 #[derive(Debug)]
@@ -80,12 +79,6 @@ impl Runner for LintRunner {
             }
         };
 
-        let extensions = VALID_EXTENSIONS
-            .iter()
-            .chain(LINT_PARTIAL_LOADER_EXT.iter())
-            .copied()
-            .collect::<Vec<&'static str>>();
-
         let config_search_result =
             Self::find_oxlint_config(&self.cwd, basic_options.config.as_ref());
 
@@ -172,7 +165,7 @@ impl Runner for LintRunner {
         }
 
         let walker = Walk::new(&paths, &ignore_options, override_builder);
-        let paths = walker.with_extensions(Extensions(extensions)).paths();
+        let paths = walker.paths();
 
         let number_of_files = paths.len();
 

apps/oxlint/src/walk.rs

@@ -1,7 +1,7 @@
 use std::{ffi::OsStr, path::PathBuf, sync::Arc, sync::mpsc};
 
 use ignore::{DirEntry, overrides::Override};
-use oxc_span::VALID_EXTENSIONS;
+use oxc_linter::LINTABLE_EXTENSIONS;
 
 use crate::cli::IgnoreOptions;
 
@@ -10,7 +10,7 @@ pub struct Extensions(pub Vec<&'static str>);
 
 impl Default for Extensions {
     fn default() -> Self {
-        Self(VALID_EXTENSIONS.to_vec())
+        Self(LINTABLE_EXTENSIONS.to_vec())
     }
 }
 
@@ -108,6 +108,7 @@ impl Walk {
         receiver.into_iter().flatten().collect()
     }
 
+    #[cfg_attr(not(test), expect(dead_code))]
     pub fn with_extensions(mut self, extensions: Extensions) -> Self {
         self.extensions = extensions;
         self

crates/oxc_language_server/Cargo.toml

@@ -28,7 +28,6 @@ oxc_diagnostics = { workspace = true }
 oxc_linter = { workspace = true }
 oxc_parser = { workspace = true }
 oxc_semantic = { workspace = true }
-oxc_span = { workspace = true }
 
 cow-utils = { workspace = true }
 env_logger = { workspace = true, features = ["humantime"] }

crates/oxc_language_server/fixtures/linter/astro/debugger.astro

@@ -0,0 +1,20 @@
+---
+debugger
+---
+
+<!-- Store the message prop as a data attribute. -->
+<astro-greet data-message={message}>
+  <button>Say hi!</button>
+</astro-greet>
+
+<script asdf >
+  debugger
+</script>
+
+<script asdf>
+  debugger
+</script>
+
+<script>
+  debugger
+</script>

crates/oxc_language_server/fixtures/linter/svelte/debugger.svelte

@@ -0,0 +1,23 @@
+<script>
+	debugger;
+
+	export let title;
+	export let person;
+
+	// this will update `document.title` whenever
+	// the `title` prop changes
+	$: document.title = title;
+
+	$: {
+		console.log(`multiple statements can be combined`);
+		console.log(`the current title is ${title}`);
+	}
+
+	// this will update `name` when 'person' changes
+	$: ({ name } = person);
+
+	// don't do this. it will run before the previous line
+	let name2 = name;
+</script>
+
+<h1>Hello {name}!</h1>

crates/oxc_language_server/fixtures/linter/vue/debugger.vue

@@ -0,0 +1,12 @@
+<template>
+    <div>Hello World</div>
+</template>
+
+<script>
+    debugger
+</script>
+
+<script setup lang="ts" generic="T extends Record<string, string>">
+    let foo: T; // test ts syntax
+    debugger;
+</script>

crates/oxc_language_server/src/linter/isolated_lint_handler.rs

@@ -12,12 +12,11 @@ use tower_lsp::lsp_types::{self, DiagnosticRelatedInformation, DiagnosticSeverit
 use oxc_allocator::Allocator;
 use oxc_diagnostics::{Error, NamedSource};
 use oxc_linter::{
-    Linter, ModuleRecord,
-    loader::{JavaScriptSource, LINT_PARTIAL_LOADER_EXT, Loader},
+    LINTABLE_EXTENSIONS, Linter, ModuleRecord,
+    loader::{JavaScriptSource, Loader},
 };
 use oxc_parser::{ParseOptions, Parser};
 use oxc_semantic::SemanticBuilder;
-use oxc_span::VALID_EXTENSIONS;
 
 use crate::DiagnosticReport;
 use crate::linter::error_with_position::{ErrorReport, ErrorWithPosition, FixedContent};
@@ -187,9 +186,8 @@ impl IsolatedLintHandler {
 
     fn should_lint_path(path: &Path) -> bool {
         static WANTED_EXTENSIONS: OnceLock<FxHashSet<&'static str>> = OnceLock::new();
-        let wanted_exts = WANTED_EXTENSIONS.get_or_init(|| {
-            VALID_EXTENSIONS.iter().chain(LINT_PARTIAL_LOADER_EXT.iter()).copied().collect()
-        });
+        let wanted_exts =
+            WANTED_EXTENSIONS.get_or_init(|| LINTABLE_EXTENSIONS.iter().copied().collect());
 
         path.extension()
             .and_then(std::ffi::OsStr::to_str)

crates/oxc_language_server/src/linter/server_linter.rs

@@ -90,4 +90,11 @@ mod test {
         Tester::new_with_linter(linter)
             .test_and_snapshot_single_file("fixtures/linter/regexp_feature/index.ts");
     }
+
+    #[test]
+    fn test_frameworks() {
+        Tester::new().test_and_snapshot_single_file("fixtures/linter/astro/debugger.astro");
+        Tester::new().test_and_snapshot_single_file("fixtures/linter/vue/debugger.vue");
+        Tester::new().test_and_snapshot_single_file("fixtures/linter/svelte/debugger.svelte");
+    }
 }

crates/oxc_language_server/src/linter/snapshots/fixtures_linter_astro_debugger.astro.snap

@@ -0,0 +1,49 @@
+---
+source: crates/oxc_language_server/src/linter/tester.rs
+---
+code: "eslint(no-debugger)"
+code_description.href: "https://oxc.rs/docs/guide/usage/linter/rules/eslint/no-debugger"
+message: "`debugger` statement is not allowed\nhelp: Delete this code."
+range: Range { start: Position { line: 1, character: 0 }, end: Position { line: 1, character: 8 } }
+related_information[0].message: ""
+related_information[0].location.uri: "file://<variable>/fixtures/linter/astro/debugger.astro"
+related_information[0].location.range: Range { start: Position { line: 1, character: 0 }, end: Position { line: 1, character: 8 } }
+severity: Some(Warning)
+source: Some("oxc")
+tags: None
+            
+
+code: "eslint(no-debugger)"
+code_description.href: "https://oxc.rs/docs/guide/usage/linter/rules/eslint/no-debugger"
+message: "`debugger` statement is not allowed\nhelp: Delete this code."
+range: Range { start: Position { line: 10, character: 2 }, end: Position { line: 10, character: 10 } }
+related_information[0].message: ""
+related_information[0].location.uri: "file://<variable>/fixtures/linter/astro/debugger.astro"
+related_information[0].location.range: Range { start: Position { line: 10, character: 2 }, end: Position { line: 10, character: 10 } }
+severity: Some(Warning)
+source: Some("oxc")
+tags: None
+            
+
+code: "eslint(no-debugger)"
+code_description.href: "https://oxc.rs/docs/guide/usage/linter/rules/eslint/no-debugger"
+message: "`debugger` statement is not allowed\nhelp: Delete this code."
+range: Range { start: Position { line: 14, character: 2 }, end: Position { line: 14, character: 10 } }
+related_information[0].message: ""
+related_information[0].location.uri: "file://<variable>/fixtures/linter/astro/debugger.astro"
+related_information[0].location.range: Range { start: Position { line: 14, character: 2 }, end: Position { line: 14, character: 10 } }
+severity: Some(Warning)
+source: Some("oxc")
+tags: None
+            
+
+code: "eslint(no-debugger)"
+code_description.href: "https://oxc.rs/docs/guide/usage/linter/rules/eslint/no-debugger"
+message: "`debugger` statement is not allowed\nhelp: Delete this code."
+range: Range { start: Position { line: 18, character: 2 }, end: Position { line: 18, character: 10 } }
+related_information[0].message: ""
+related_information[0].location.uri: "file://<variable>/fixtures/linter/astro/debugger.astro"
+related_information[0].location.range: Range { start: Position { line: 18, character: 2 }, end: Position { line: 18, character: 10 } }
+severity: Some(Warning)
+source: Some("oxc")
+tags: None

crates/oxc_language_server/src/linter/snapshots/fixtures_linter_svelte_debugger.svelte.snap

@@ -0,0 +1,13 @@
+---
+source: crates/oxc_language_server/src/linter/tester.rs
+---
+code: "eslint(no-debugger)"
+code_description.href: "https://oxc.rs/docs/guide/usage/linter/rules/eslint/no-debugger"
+message: "`debugger` statement is not allowed\nhelp: Delete this code."
+range: Range { start: Position { line: 1, character: 1 }, end: Position { line: 1, character: 10 } }
+related_information[0].message: ""
+related_information[0].location.uri: "file://<variable>/fixtures/linter/svelte/debugger.svelte"
+related_information[0].location.range: Range { start: Position { line: 1, character: 1 }, end: Position { line: 1, character: 10 } }
+severity: Some(Warning)
+source: Some("oxc")
+tags: None

crates/oxc_language_server/src/linter/snapshots/fixtures_linter_vue_debugger.vue.snap

@@ -0,0 +1,25 @@
+---
+source: crates/oxc_language_server/src/linter/tester.rs
+---
+code: "eslint(no-debugger)"
+code_description.href: "https://oxc.rs/docs/guide/usage/linter/rules/eslint/no-debugger"
+message: "`debugger` statement is not allowed\nhelp: Delete this code."
+range: Range { start: Position { line: 5, character: 4 }, end: Position { line: 5, character: 12 } }
+related_information[0].message: ""
+related_information[0].location.uri: "file://<variable>/fixtures/linter/vue/debugger.vue"
+related_information[0].location.range: Range { start: Position { line: 5, character: 4 }, end: Position { line: 5, character: 12 } }
+severity: Some(Warning)
+source: Some("oxc")
+tags: None
+            
+
+code: "eslint(no-debugger)"
+code_description.href: "https://oxc.rs/docs/guide/usage/linter/rules/eslint/no-debugger"
+message: "`debugger` statement is not allowed\nhelp: Delete this code."
+range: Range { start: Position { line: 10, character: 4 }, end: Position { line: 10, character: 13 } }
+related_information[0].message: ""
+related_information[0].location.uri: "file://<variable>/fixtures/linter/vue/debugger.vue"
+related_information[0].location.range: Range { start: Position { line: 10, character: 4 }, end: Position { line: 10, character: 13 } }
+severity: Some(Warning)
+source: Some("oxc")
+tags: None

crates/oxc_language_server/src/linter/tester.rs

@@ -102,8 +102,10 @@ impl Tester<'_> {
     #[expect(clippy::disallowed_methods)]
     pub fn test_and_snapshot_single_file(&self, relative_file_path: &str) {
         let uri = get_file_uri(relative_file_path);
-        let content = std::fs::read_to_string(uri.to_file_path().unwrap())
-            .expect("could not read fixture file");
+        let content = match std::fs::read_to_string(uri.to_file_path().unwrap()) {
+            Ok(content) => content,
+            Err(err) => panic!("could not read fixture file: {err}: {relative_file_path}"),
+        };
         let reports = self.server_linter.run_single(&uri, Some(content)).unwrap();
         let snapshot = if reports.is_empty() {
             "No diagnostic reports".to_string()

crates/oxc_linter/Cargo.toml

@@ -41,6 +41,7 @@ oxc_syntax = { workspace = true, features = ["serialize"] }
 
 #
 bitflags = { workspace = true }
+constcat = { workspace = true }
 convert_case = { workspace = true }
 cow-utils = { workspace = true }
 fast-glob = { workspace = true }

crates/oxc_linter/src/lib.rs

@@ -38,6 +38,7 @@ pub use crate::{
     context::LintContext,
     fixer::FixKind,
     frameworks::FrameworkFlags,
+    loader::LINTABLE_EXTENSIONS,
     module_record::ModuleRecord,
     options::LintOptions,
     options::{AllowWarnDeny, InvalidFilterKind, LintFilter, LintFilterKind},

crates/oxc_linter/src/loader/mod.rs

@@ -4,7 +4,7 @@ use oxc_span::SourceType;
 
 mod partial_loader;
 mod source;
-pub use partial_loader::{LINT_PARTIAL_LOADER_EXT, PartialLoader};
+pub use partial_loader::{LINT_PARTIAL_LOADER_EXTENSIONS, LINTABLE_EXTENSIONS, PartialLoader};
 pub use source::JavaScriptSource;
 
 // TODO: use oxc_resolver::FileSystem. We can't do so until that crate exposes FileSystemOs
@@ -19,7 +19,7 @@ impl Loader {
             || path
                 .extension()
                 .and_then(std::ffi::OsStr::to_str)
-                .is_some_and(|ext| LINT_PARTIAL_LOADER_EXT.contains(&ext))
+                .is_some_and(|ext| LINT_PARTIAL_LOADER_EXTENSIONS.contains(&ext))
     }
 
     /// # Errors

crates/oxc_linter/src/loader/partial_loader/mod.rs

@@ -2,13 +2,22 @@ mod astro;
 mod svelte;
 mod vue;
 
+use oxc_span::VALID_EXTENSIONS;
+
 pub use self::{astro::AstroPartialLoader, svelte::SveltePartialLoader, vue::VuePartialLoader};
 use crate::loader::JavaScriptSource;
 
 const SCRIPT_START: &str = "<script";
 const SCRIPT_END: &str = "</script>";
 
-pub const LINT_PARTIAL_LOADER_EXT: &[&str] = &["vue", "astro", "svelte"];
+/// File extensions that can contain JS/TS code in certain parts, such as in `<script>` tags, and can
+/// be loaded using the [`PartialLoader`].
+pub const LINT_PARTIAL_LOADER_EXTENSIONS: &[&str] = &["vue", "astro", "svelte"];
+
+/// All valid JavaScript/TypeScript extensions, plus additional framework files that
+/// contain JavaScript/TypeScript code in them (e.g., Vue, Astro, Svelte, etc.).
+pub const LINTABLE_EXTENSIONS: &[&str] =
+    constcat::concat_slices!([&str]: VALID_EXTENSIONS, LINT_PARTIAL_LOADER_EXTENSIONS);
 
 pub struct PartialLoader;
 

crates/oxc_linter/src/rules/unicorn/no_empty_file.rs

@@ -4,7 +4,10 @@ use oxc_macros::declare_oxc_lint;
 use oxc_span::Span;
 
 use crate::{
-    context::LintContext, loader::LINT_PARTIAL_LOADER_EXT, rule::Rule, utils::is_empty_stmt,
+    context::{ContextHost, LintContext},
+    loader::LINT_PARTIAL_LOADER_EXTENSIONS,
+    rule::Rule,
+    utils::is_empty_stmt,
 };
 
 fn no_empty_file_diagnostic(span: Span) -> OxcDiagnostic {
@@ -39,13 +42,6 @@ declare_oxc_lint!(
 
 impl Rule for NoEmptyFile {
     fn run_once(&self, ctx: &LintContext) {
-        if ctx
-            .file_path()
-            .extension()
-            .is_some_and(|ext| LINT_PARTIAL_LOADER_EXT.contains(&ext.to_string_lossy().as_ref()))
-        {
-            return;
-        }
         let Some(root) = ctx.nodes().root_node() else {
             return;
         };
@@ -67,6 +63,12 @@ impl Rule for NoEmptyFile {
         span.end = std::cmp::min(span.end, 100);
         ctx.diagnostic(no_empty_file_diagnostic(span));
     }
+
+    fn should_run(&self, ctx: &ContextHost) -> bool {
+        ctx.file_path().extension().is_some_and(|ext| {
+            !LINT_PARTIAL_LOADER_EXTENSIONS.contains(&ext.to_string_lossy().as_ref())
+        })
+    }
 }
 
 fn has_triple_slash_directive(ctx: &LintContext<'_>) -> bool {

crates/oxc_linter/src/service/runtime.rs

@@ -25,7 +25,7 @@ use oxc_span::{CompactStr, SourceType, VALID_EXTENSIONS};
 use super::LintServiceOptions;
 use crate::{
     Fixer, Linter, Message,
-    loader::{JavaScriptSource, LINT_PARTIAL_LOADER_EXT, PartialLoader},
+    loader::{JavaScriptSource, LINT_PARTIAL_LOADER_EXTENSIONS, PartialLoader},
     module_record::ModuleRecord,
     utils::read_to_string,
 };
@@ -175,7 +175,7 @@ impl Runtime {
     ) -> Option<Result<(SourceType, String), Error>> {
         let source_type = SourceType::from_path(path);
         let not_supported_yet =
-            source_type.as_ref().is_err_and(|_| !LINT_PARTIAL_LOADER_EXT.contains(&ext));
+            source_type.as_ref().is_err_and(|_| !LINT_PARTIAL_LOADER_EXTENSIONS.contains(&ext));
         if not_supported_yet {
             return None;
         }

crates/oxc_span/src/source_type/mod.rs

@@ -97,7 +97,7 @@ impl ContentEq for SourceType {
 }
 
 /// Valid file extensions
-pub const VALID_EXTENSIONS: [&str; 8] = ["js", "mjs", "cjs", "jsx", "ts", "mts", "cts", "tsx"];
+pub const VALID_EXTENSIONS: &[&str] = &["js", "mjs", "cjs", "jsx", "ts", "mts", "cts", "tsx"];
 
 impl SourceType {
     /// Creates a [`SourceType`] representing a regular [`JavaScript`] file.