Setting "ArrayExpression": "off" in indent rule causes eslint to crash

[gpascale]

Tell us about your environment

• ESLint Version: 4.5.0 (tested various versions back to 4.0.0 and saw same issue)
• Node Version: 6.9.1
• npm Version: 3.10.8

What parser (default, Babel-ESLint, etc.) are you using?

default

Please show your full configuration:

Configuration

{
  "env": {
    "browser": true,
    "commonjs": true,
    "es6": true
  },
  "extends": "eslint:recommended",
  "parserOptions": {
    "ecmaFeatures": {
      "experimentalObjectRestSpread": true,
      "jsx": true
    },
    "sourceType": "module"
  },
  "plugins": [
    "react",
    "json"
  ],
  "rules": {
    // want to add "ArrayExpression": "first" but eslint has a bug
    "indent": [ "error", 2, { "SwitchCase": 1, "flatTernaryExpressions": true, "ArrayExpression": "off", "ObjectExpression": "off" } ],
    "linebreak-style": [ "error", "unix" ],
    "quotes": [ "error", "single" ],
    "semi": [ "error", "always" ],
    "react/jsx-uses-vars": 1,
    "no-unused-vars": [ "warn", { "vars": "all" } ],
    "brace-style": [ "error", "stroustrup", { "allowSingleLine": true } ]
  }
}

What did you do? Please include the actual source code causing the issue.

I'm just running eslint on my small/medium sized node/react/es6 codebase. I can't tell exactly what part of my code is causing the problem because an error is happening in eslint itself.

What did you expect to happen?

The linter to run normally

What actually happened? Please include the actual, raw output from ESLint.

Cannot read property 'range' of null
TypeError: Cannot read property 'range' of null
at SourceCode.getTokenBefore (/home/git/myproject/node_modules/eslint/lib/token-store/index.js:303:17)
at getFirstToken (/home/git/myproject/node_modules/eslint/lib/rules/indent.js:784:40)
at elements.forEach (/home/git/myproject/node_modules/eslint/lib/rules/indent.js:806:41)
at Array.forEach (native)
at addElementListIndent (/home/git/myproject/node_modules/eslint/lib/rules/indent.js:804:22)
at Object.ArrayExpression, ArrayPattern [as listener] (/home/git/myproject/node_modules/eslint/lib/rules/indent.js:965:17)
at Program:exit.listenerCallQueue.filter.forEach.nodeInfo (/home/git/myproject/node_modules/eslint/lib/rules/indent.js:1444:55)
at Array.forEach (native)
at Linter.Program:exit (/home/git/myproject/node_modules/eslint/lib/rules/indent.js:1444:26)
at emitOne (events.js:101:20)
at Linter.emit (events.js:188:7)

NOTE:
The culprit here seems to be setting "ArrayExpression": "off". If I omit it or set it to "first", the linter runs as expected.

[not-an-aardvark]

Thanks for the report. This seems like it might be a bug, but it's hard to tell without having an example of code that causes the issue. The ArrayExpression: off option certainly works for some code, so I can't reproduce the problem based on the information you've provided.

If you add the --debug flag when running ESLint, it will print out some messages when it lints each file. If you look at the last few messages that get printed before the crash, it should be possible to determine which file was being linted when the crash occurred.

[gpascale]

Thanks for the tip. Using --debug I was able to find the file where it was crashing and ultimately narrow it down to a single line. I verified that running eslint on a file containing nothing but this line will trigger the error.

const [, ...myArrayMinusOne] = myArray;

It's possible (read: probable) that I don't have eslint properly configured for all my babel/eswhatever nonsense, but regardless, it would of course be better if it didn't crash.

[not-an-aardvark]

Thanks, I was able to reproduce this issue.