eslint --init throws: TypeError: Cannot read property '0' of undefined

[gfx]

eslint --init fails when my enviroment:

• ESLint v3.12.2
• NodeJS v6.9.2
• npm 3.10.8

with the answers:

$ eslint --init
? How would you like to configure ESLint? Inspect your JavaScript file(s)
? Which file(s), path(s), or glob(s) should be examined? client/
? What format do you want your config file to be in? JSON
? Are you using ECMAScript 6 features? Yes
? Are you using ES6 modules? Yes
? Where will your code run? Browser
? Do you use CommonJS? No
? Do you use JSX? Yes
? Do you use React? Yes
Determining Config: 23% [=======-----------------------] 1.0s elapsed, eta 3.3s Cannot read property '0' of undefined
TypeError: Cannot read property '0' of undefined
    at lintResults.forEach.result (~/.ghq/github.com/proj/node_modules/eslint/lib/config/autoconfig.js:301:60)
    at Array.forEach (native)
    at ruleSets.forEach.ruleSet (~/.ghq/github.com/proj/node_modules/eslint/lib/config/autoconfig.js:296:29)
    at Array.forEach (native)
    at filenames.forEach.filename (~/.ghq/github.com/proj/node_modules/eslint/lib/config/autoconfig.js:292:22)
    at Array.forEach (native)
    at Registry.lintSourceCode (~/.ghq/github.com/proj/node_modules/eslint/lib/config/autoconfig.js:287:19)
    at configureRules (~/.ghq/github.com/proj/node_modules/eslint/lib/config/config-initializer.js:148:25)
    at processAnswers (~/.ghq/github.com/proj/node_modules/eslint/lib/config/config-initializer.js:248:18)
    at inquirer.prompt.err [as completed] (~/.ghq/github.com/proj/node_modules/eslint/lib/config/config-initializer.js:418:30)

with a patch to autoconfig.js:

# line 301
+                    console.log(lintedRegistry.rules[result.ruleId]);
+                    console.log(result.ruleId, ruleSetIdx);
                     if (lintedRegistry.rules[result.ruleId][ruleSetIdx]) {
                         lintedRegistry.rules[result.ruleId][ruleSetIdx].errorCount += 1;
                     }

it shows:

undefined
import/extensions 0

Seams lintedRegistry.rules["import/extensions"] is missing.

[mysticatea]

Thank you for the report!

Looks like a bug.
I guess that eslint --init command handles only core rules, but import/extensions was appeared.

[alberto]

@gfx any idea how eslint-plugin-import got installed and enabled there? I can't reproduce this

[gfx]

@alberto I just add eslint-plugin-import to devDependencies in package.json and enable it in .elsintrc.

[nzakas]

@IanVS any idea why a plugin rule would show up in auto config?

[IanVS]

I think that one of his files has an inline config that is enabling import/extensions, and the code is not properly guarded. It guards against core rules, as a result of the fix to #5992, but we also need to check for plugin rules. I can fix this quickly.