AssertionError [ERR_ASSERTION]: 'newBasePath' should be an absolute path

[drkestel]

Windows
Node v12.13.0
npm v6.13.6
eslint 6.8.0
Parser: @typescript-eslint/parser
Bash terminal

eslint config:

"use strict";
const allExtensions = [".ts", ".tsx", ".d.ts", ".js", ".jsx"];
module.exports = {
    env: {
        "browser": true,
        "es6": true,
    },
    parser: "@typescript-eslint/parser",
    parserOptions: {
        project: "./tsconfig.json",
        sourceType: "module",
    },
    plugins: [
        "import",
        "@typescript-eslint",
        "@typescript-eslint/tslint",
    ],
    settings: {
        "import/extensions": allExtensions,
        "import/parsers": {
            "@typescript-eslint/parser": [".ts", ".tsx", ".d.ts"],
        },
        "import/resolver": {
            "node": {
                "extensions": allExtensions,
            },
        },
    },
    rules: {
     
        "import/no-deprecated": "warn",
        "@typescript-eslint/no-unused-vars": "error",
        "@typescript-eslint/tslint/config": [
            "warn",
            {
                "rules": {
                    "deprecation": true,
                },
            },
        ],
    },
};

I'm currently using a globally installed npm package (call it foo cli) that wraps eslint. I have a workspace in c:\src\myproject. foo cli has an internal reference to eslint 6.8.0. When I run ap lint from c:\src\myproject, foo cli invokes eslint with some default parameters, and I get the error from the bug title. Here's the raw output:

/c/myproject (master)
$ ap lint
Running C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\.bin\eslint.cmd **/*.ts --ignore-path C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\lint\.eslintignore -c C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\lint\.eslintrc.json --resolve-plugins-relative-to C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\lint
AssertionError [ERR_ASSERTION]: 'newBasePath' should be an absolute path.
    at IgnorePattern.getPatternsRelativeTo (C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\eslint\lib\cli-engine\config-array\ignore-pattern.js:210:9)
    at C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\eslint\lib\cli-engine\config-array\ignore-pattern.js:150:42
    at Array.map (<anonymous>)
    at Function.createIgnore (C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\eslint\lib\cli-engine\config-array\ignore-pattern.js:150:31)
    at createConfig (C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\eslint\lib\cli-engine\config-array\config-array.js:282:40)
    at ConfigArray.extractConfig (C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\eslint\lib\cli-engine\config-array\config-array.js:452:33)
    at FileEnumerator._isIgnoredFile (C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\eslint\lib\cli-engine\file-enumerator.js:479:24)
    at FileEnumerator._iterateFilesRecursive (C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\eslint\lib\cli-engine\file-enumerator.js:407:38)
    at _iterateFilesRecursive.next (<anonymous>)
    at FileEnumerator.iterateFiles (C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\eslint\lib\cli-engine\file-enumerator.js:251:49)

I believe the problem exists in ignore-pattern.js and was introduced in this pull request: https://github.com/eslint/eslint/pull/12274/files

If I add some debug logging to IgnorePattern.getCommonAncestorPath:

function getCommonAncestorPath(sourcePaths) {
    let result = sourcePaths[0];

    for (let i = 1; i < sourcePaths.length; ++i) {
        const a = result;
        const b = sourcePaths[i];

        // Set the shorter one (it's the common ancestor if one includes the other).
        result = a.length < b.length ? a : b;

        // Set the common ancestor.
        for (let j = 0, lastSepPos = 0; j < a.length && j < b.length; ++j) {
            if (a[j] !== b[j]) {
                result = a.slice(0, lastSepPos);
                break;
            }
            if (a[j] === path.sep) {
                lastSepPos = j;
            }
        }
    }
    console.log("**: ", { result: result, sep: path.sep, sourcePaths: sourcePaths }); // new line here
    return result || path.sep;
}

I see the following output:

/c/myproject (master)
$ ap lint
Running C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\.bin\eslint.cmd **/*.ts --ignore-path C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\lint\.eslintignore -c C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\lint\.eslintrc.json --resolve-plugins-relative-to C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\lint
**:  {
  result: 'C:\\src\\myproject',
  sep: '\\',
  sourcePaths: [ 'C:\\src\\myproject' ]
}
**:  {
  result: 'C:\\src\\myproject',
  sep: '\\',
  sourcePaths: [ 'C:\\src\\myproject' ]
}
**:  {
  result: 'C:',
  sep: '\\',
  sourcePaths: [
    'C:\\src\\myproject',
    'C:\\Users\\drkestel\\AppData\\Roaming\\npm\\node_modules\\@foocli\\lint'
  ]
}
AssertionError [ERR_ASSERTION]: 'newBasePath' should be an absolute path.
    at IgnorePattern.getPatternsRelativeTo (C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\eslint\lib\cli-engine\config-array\ignore-pattern.js:210:9)
    at C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\eslint\lib\cli-engine\config-array\ignore-pattern.js:150:42
    at Array.map (<anonymous>)
    at Function.createIgnore (C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\eslint\lib\cli-engine\config-array\ignore-pattern.js:150:31)
    at createConfig (C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\eslint\lib\cli-engine\config-array\config-array.js:282:40)
    at ConfigArray.extractConfig (C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\eslint\lib\cli-engine\config-array\config-array.js:452:33)
    at FileEnumerator._isIgnoredFile (C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\eslint\lib\cli-engine\file-enumerator.js:479:24)
    at FileEnumerator._iterateFilesRecursive (C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\eslint\lib\cli-engine\file-enumerator.js:407:38)
    at _iterateFilesRecursive.next (<anonymous>)
    at FileEnumerator.iterateFiles (C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\eslint\lib\cli-engine\file-enumerator.js:251:49)

/c/myproject (master)
$

Notice the result: 'C:', - that is not considered a valid absolute path.

Interestingly enough, I can mitigate the problem by using windows cmd.exe and setting my current prompt to c:\ (lowercase, as opposed to C:\). Because c:\ != C:\, it works. See the output:

c:\src\myproject>ap lint
Running C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\node_modules\.bin\eslint.cmd **/*.ts --ignore-path C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\lint\.eslintignore -c C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\lint\.eslintrc.json --resolve-plugins-relative-to C:\Users\drkestel\AppData\Roaming\npm\node_modules\@foocli\lint
**:  {
  result: 'c:\\src\\myproject',
  sep: '\\',
  sourcePaths: [ 'c:\\src\\myproject' ]
}
**:  {
  result: 'c:\\src\\myproject',
  sep: '\\',
  sourcePaths: [ 'c:\\src\\myproject' ]
}
**:  {
  result: '',
  sep: '\\',
  sourcePaths: [
    'c:\\src\\myproject',
    'C:\\Users\\drkestel\\AppData\\Roaming\\npm\\node_modules\\@foocli\\lint'
  ]
}
**:  {
  result: '',
  sep: '\\',
  sourcePaths: [
    'c:\\src\\myproject',
    'C:\\Users\\drkestel\\AppData\\Roaming\\npm\\node_modules\\@foocli\\lint'
  ]
}

c:\src\myproject\Client\Index.ts
  66:5   warning  Missing return type on function                 @typescript-eslint/explicit-function-return-type
  67:17  error    'container' is assigned a value but never used  @typescript-eslint/no-unused-vars
  68:15  error    'id' is assigned a value but never used         @typescript-eslint/no-unused-vars

... more valid linting

I can also mitigate the problem by making the following code change to ignore-pattern.js:

function getCommonAncestorPath(sourcePaths) {
    let result = sourcePaths[0];

    for (let i = 1; i < sourcePaths.length; ++i) {
        const a = result;
        const b = sourcePaths[i];

        // Set the shorter one (it's the common ancestor if one includes the other).
        result = a.length < b.length ? a : b;

        // Set the common ancestor.
        for (let j = 0, lastSepPos = 0; j < a.length && j < b.length; ++j) {
            if (a[j] !== b[j]) {
                result = a.slice(0, lastSepPos);
                break;
            }
            if (a[j] === path.sep) {
                lastSepPos = j;
            }
        }
    }
    // this was the previous return statement
    // return result || path.sep;

    // new return statement
    let resolvedResult = result || path.sep;
    if (resolvedResult && resolvedResult.endsWith(":")) {
        resolvedResult = resolvedResult + path.sep;
    }
    return resolvedResult;
}

[kaicataldo]

Thanks for the detailed bug report. This does seem like a bug to me. Looking at how paths work in WIndows in Microsoft's documentation, it does look like we need to fix this algorithm to not remove the separator from C:, since "C:" is considered relative while "C:\\" is considered absolute.

[nickharris]

@kaicataldo are you happy with drkestels //new return statement from the snippet above or would you prefer just update result = a.slice(0, lastSepPos); to result = a.slice(0, lastSepPos + 1);

[kaicataldo]

This makes sense to me:

    let resolvedResult = result || path.sep;
    if (resolvedResult && resolvedResult.endsWith(":")) {
        resolvedResult = resolvedResult + path.sep;
    }
    return resolvedResult;

I'd be curious to hear from other team members who have more experience with Windows think. I'm no expert on Windows path gotchas.

[nickharris]

@kaicataldo how about something like this https://github.com/eslint/eslint/pull/13078/files

[nickharris]

@nzakas @kaicataldo do you have docs on your release pipeline? I am trying to understand rough timelines around when this will be available to consume from npmjs in an alpha build and then an official release?

[nzakas]

The timeline for major releases is a bit ad-hoc, and given the current worldwide situation and team members dealing with that and other personal issues, I can’t really give you any specify guidance. We wanted to get 7.0.0 out by May, and the next alpha was supposed to be last week but we couldn’t get stuff done due to low availability.

[nickharris]

no probs, completely understand the current situation was just curious so i can plan around it. take care, nick.

[kaicataldo]

@nickharris v7.0.0 was released last Friday!

[nickharris]

yup already using it :) thank you!