Bug: All ESLint 8 commands fail if the project path contains URL-encoded characters

[chucknelson]

Environment

Node version: 14.18.2
npm version: 6.14.15
Local ESLint version: 8.12.0
Global ESLint version: none
Operating System: Darwin 20.6.0 (macOS Big Sur)

What parser are you using?

@typescript-eslint/parser

What did you do?

Try to run any ESLint command in a project path with a URL encoded character, such as /my%2Fproject/yarn eslint --env-info.

What did you expect to happen?

Command would succeed with the expected output, such as:

/Users/myuser/my%2Fproject/node_modules/.bin/eslint --debug --env-info
eslint:cli CLI args: [ '--debug', '--env-info' ] +0ms
Environment Info:

Node version: v14.18.2
npm version: v6.14.15
Local ESLint version: v8.12.0 (Currently used)
Global ESLint version: Not found
Operating System: darwin 20.6.0

What actually happened?

Example

A project with eslint@8.12.0 installed is in the following path that includes a URL-encoded slash:

/Users/myuser/my%2Fproject

Run any ESLint command, such as --env-info and it fails with the following:

/Users/myuser/my%2Fproject/node_modules/.bin/eslint --debug --env-info

Oops! Something went wrong! :(

ESLint: 8.12.0

TypeError [ERR_INVALID_ARG_VALUE]: The argument 'filename' must be a file URL object, file URL string, or absolute path string. Received 'file:///Users/d108059/Development/tmp/my%2Fproject/node_modules/@eslint/eslintrc/dist/eslintrc.cjs'
    at new NodeError (internal/errors.js:322:7)
    at Function.createRequire (internal/modules/cjs/loader.js:1182:13)
    at Object.<anonymous> (/Users/d108059/Development/tmp/my%2Fproject/node_modules/@eslint/eslintrc/dist/eslintrc.cjs:2383:26)
    at Module._compile (/Users/d108059/Development/tmp/my%2Fproject/node_modules/v8-compile-cache/v8-compile-cache.js:192:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1114:10)
    at Module.load (internal/modules/cjs/loader.js:950:32)
    at Function.Module._load (internal/modules/cjs/loader.js:790:12)
    at Module.require (internal/modules/cjs/loader.js:974:19)
    at require (/Users/d108059/Development/tmp/my%2Fproject/node_modules/v8-compile-cache/v8-compile-cache.js:159:20)
    at Object.<anonymous> (/Users/d108059/Development/tmp/my%2Fproject/node_modules/eslint/lib/cli-engine/cli-engine.js:33:5)
error Command failed with exit code 2.

Participation

• I am willing to submit a pull request for this issue.

Additional comments

Prior versions of ESLint, such as 7.32.0, work fine with these paths. For example, this works fine:

/Users/myuser/my%2Fproject/node_modules/.bin/eslint --debug --env-info
eslint:cli CLI args: [ '--debug', '--env-info' ] +0ms
Environment Info:

Node version: v14.18.2
npm version: v6.14.15
Local ESLint version: v7.32.0 (Currently used)
Global ESLint version: Not found
Operating System: darwin 20.6.0

[nzakas]

This error is coming from require(), which means it’s coming from inside Node.js. Here’s the line:

eslint/lib/cli-engine/cli-engine.js

Line 33 in bb4c0d5

} = require("@eslint/eslintrc");

Do you see this behavior in ESLint v8.0.0?

[fasttime]

Looking at the line /@eslint/eslintrc/dist/eslintrc.cjs:2383:26 hinted by the stack trace, I can find this code:

const require$1 = Module.createRequire((typeof document === 'undefined' ? new (require('u' + 'rl').URL)('file:' + __filename).href : (document.currentScript && document.currentScript.src || new URL('eslintrc.cjs', document.baseURI).href)));

You can see the whole file here: https://unpkg.com/@eslint/eslintrc@1.2.1/dist/eslintrc.cjs

The corresponding source code is this harmless-looking line in eslintrc:

const require = createRequire(import.meta.url);

which can be found here: https://github.com/eslint/eslintrc/blob/9b719813fc6f023b722168a4f67d895106e875ce/lib/config-array-factory.js#L58

From what I can tell, the generated code is trying to create a file URL from __filename, but doing so in a very error-prone way: 'file:' + __filename rather than using the builtin Node function pathToFileURL. The resulting URL will contain an escaped slash (%2F) rather than the proper escape sequence for "%2F" (%252F).

This is not a bug in ESLint, but rather an issue with the build tools used in eslintrc, most probably Rollup.

[nzakas]

@fasttime wow, thanks for the detailed analysis. We will look deeper into this.

[mdjermanovic]

@fasttime thanks for all the details! I prepared a possible fix based on your suggestion.

eslint/eslintrc#77

[chucknelson]

Thanks all for the quick response! ❤️