biome correctness/noGlobalDirnameFilename: fix changes program behavior

Hypothesis Nemotron 3 Super predicted to fire fired 1×

comments attached to the removed or moved code

Program

Output

(no stdout)
ReferenceError: __filename 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 __filename is undefined, causing a ReferenceError before the fix. The rewrite to import.meta.filename is the documented equivalent for ES modules, so the behavior change stems from the module system environment, not a flaw in the fix itself.

Explanation Nemotron 3 Super unverified

The original `__filename` refers to a Node.js CommonJS variable unavailable in ES modules, causing a ReferenceError; replacing it with `import.meta.filename`, which provides the module’s file URL as a string, avoids that error but changes the value type from a filesystem path string to a URL string, altering runtime behavior for any code depending on the exact format or content of `x`. This substitution is not semantically equivalent because the two expressions produce different values despite both being defined.

Reproduce

file

prog.js (the before program)

minimized program

r1-p008.js

evidence sheet

r1-p008.md

regression fixture

r1-p008.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 · __filename usage · import.meta.filename replacement · ES module global variable

• related biomejs/biome/issues/6670 same rule area (global __filename/__dirname metavariables) but different construct (GritQL plugin metavariable not set)
• duplicate biomejs/biome/issues/4331 same rule (noGlobalDirnameFilename) and same construct (__filename/__dirname global replacement with import.meta)

Details

program

__filename /* inline */ - comment attached to removed code

hazard

comments attached to the removed or moved code

oracle

exit 1 → 0 stderr before: ReferenceError: __filename 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 16:16:41.596023239 -0400
+++ fixed.js	2026-10-17 16:16:41.866019943 -0400
@@ -1,3 +1,3 @@
 // Hazard 8
-const x = __filename /* inline note */;
+const x = import.meta.filename /* inline note */;
 console.log(x.length);

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/")) {}
 ```