biome correctness/noGlobalDirnameFilename: fix changes program behavior

Hypothesis Nemotron 3 Super predicted to fire fired 1×

Rewrite creates import.meta.dirname that shadows a outer-scope dirname variable.

Program

Output

(no stdout)
ReferenceError: __dirname is not defined in ES module scope

(no stdout)

Judge Nemotron 3 Ultra advisory program-bug · low

The program runs as an ES module where __dirname is undefined, so it crashes before the fix; after the fix it uses import.meta.dirname which exists in ES modules. The behavior change is caused by the module system, not by a semantic difference in the rewrite itself.

Explanation Nemotron 3 Super unverified

The original program uses `__dirname`, which is undefined in ES modules, causing a ReferenceError when executed. The replacement `import.meta.dirname` provides the directory name of the current module file in ES module scope, resolving the error. Since the original code fails to run due to the missing `__dirname`, while the fixed version executes successfully, the behavior changes from throwing an error to running without error—this difference in observable outcome means the rewrite is not semantics-preserving, even though it makes the code functional in ES modules. The fix alters the program’s execution path by eliminating a runtime exception.

Reproduce

file

prog.js (the before program)

minimized program

r2-p003.js

evidence sheet

r2-p003.md

regression fixture

r2-p003.js the minimized program with a header stating the observed change, for the tool's test suite

node prog.js
bunx @biomejs/biome lint --only=correctness/noGlobalDirnameFilename --write prog.js
node prog.js

Upstream search GitHub issues Tavily Nemotron 3 Super + Ultra

noGlobalDirnameFilename fix · __dirname usage · ES module global variable · import.meta.dirname replacement

• related biomejs/biome/issues/4331 same rule (noGlobalDirnameFilename) but tracking initial implementation not the fix-changes-behavior defect
• duplicate biomejs/biome/issues/11028 same rule (noGlobalDirnameFilename) and same defect (fix replaces __dirname with import.meta.dirname in contexts where it changes behavior)

Details

program

Name collision after rewrite

hazard

Rewrite creates import.meta.dirname that shadows a outer-scope dirname variable.

oracle

exit 1 → 0 stderr before: ReferenceError: __dirname is not defined in ES module scope stderr after: (none)

run

2026-10-17T20-16-26-722Z-l85y-biome-correctness_noGlobalDirnameFilename

--- orig.js	2026-10-17 16:16:49.925922655 -0400
+++ fixed.js	2026-10-17 16:16:50.190919492 -0400
@@ -1,5 +1,5 @@
 let dirname = 'outer';
-const dir = __dirname;
+const dir = import.meta.dirname;
 console.log('dirname:', dirname);
 if (typeof dirname === 'string') {
   console.log('block dirname:', dirname);

Summary

- Name: noGlobalDirnameFilename
- Fix: safe
- Default severity: info
- Available from version: 2.0.0
- Diagnostic category: lint/correctness/noGlobalDirnameFilename


Description

 Disallow the use of `__dirname` and `__filename` in the global scope.

 They are [not available in ES modules](https://nodejs.org/api/esm.html#esm_no_filename_or_dirname).
 Starting with Node.js 20.11, `import.meta.dirname` and `import.meta.filename` have been introduced in ES modules, providing identical functionality to `__dirname` and `__filename` in CommonJS (CJS).

Examples

Invalid

 ```js,expect_diagnostic
 const dirname = __dirname;
 ```

 ```js,expect_diagnostic
 const filename = __filename;
 ```

 ``` js,expect_diagnostic
 const foo = { __filename }
 ```

 ```js,expect_diagnostic
 if (__dirname.startsWith("/project/src/")) {}
 ```

Valid

 ```js
 const dirname = import.meta.dirname
 const filename = import.meta.filename
 const foo = {__filename: import.meta.filename };
 if (import.meta.dirname.startsWith("/project/src/")) {}
 ```