Webpack 2 Error with Eslint 2

[dtothefp]

Sorry for duplicate issues but I'm really unsure what repo this issue belongs in. webpack-contrib/eslint-loader#80. Looking at the updated dependencies I'm guessing this is some sort of issue with acorn versions but I'm not sure?

Webpack 2 has a dependency on "acorn": "^2.4.0", and Eslint 2 has a dependency on "espree": "^3.0.0" which in turn has a dependency on "acorn": "^2.7.0".

• Webpack 2 => "acorn": "^2.4.0"
• Eslint 2 => "espree": "^3.0.0" => "acorn": "^2.7.0"

Eslint 2 has a dependency on "espree": "^2.2.4" which in turn has NO acorn dependency so I'm guessing whatever is happening is some sort of conflict in acorn but I'm unsure how this plays out.

• Webpack 2 => "acorn": "^2.4.0"
• Eslint 1 => "espree": "^2.2.4"

I think this could be an NPM 3 semver thing where NPM tries to be smart and and sees two versions of acorn with ^2.x and extracts them out into the root of node_modules

Upon updating to Eslint 2 and Webpack 2 I get an error in espree shown below. With Webpack 1 I don't get this error, and with Webpack 2.0.7.-beta and Eslint 1.x I don't get the error as well. If you have any ideas and cold point me in the right direction I'd appreciate it.

{
  "parser": "babel-eslint",
  "plugins": [
    "react"
  ],
  "env": {
    "browser": true,
    "node": true
  },
  "parserOptions": {
    "ecmaVersion": 6,
    "sourceType": "module",
    "ecmaFeatures": {
      "arrowFunctions": true,
      "blockBindings": true,
      "experimentalObjectRestSpread": true,
      "generators": true,
      "jsx": true,
      "module": true,
      "modules": true,
      "restParams": true,
      "spread": true,
      "jsx": true
    }
  }
}

ERROR in ./src/js/index.js
Module parse failed: /Users/davidfox-powell/dev/frontend-boilerplate/node_modules/babel-loader/index.js?{"presets":["react","es2015","stage-0"],"plugins":["transform-runtime","transform-decorators-legacy","typecheck",["react-transform",{"transforms":[{"transform":"react-transform-hmr","imports":["react"],"locals":["module"]},{"transform":"react-transform-catch-errors","imports":["react","redbox-react"]}]}]]}!/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/eslint-loader/index.js!/Users/davidfox-powell/dev/frontend-boilerplate/src/js/index.js 
Cannot read property 'ecmaFeatures' of undefined
You may need an appropriate loader to handle this file type.
TypeError: Cannot read property 'ecmaFeatures' of undefined
    at Parser.parseTopLevel (/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/espree/espree.js:271:18)
    at Parser.parse (/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/acorn/dist/acorn.js:1636:17)
    at Object.parse (/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/acorn/dist/acorn.js:905:44)
    at Parser.parse (/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/webpack/lib/Parser.js:960:18)
    at Module.<anonymous> (/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/webpack/lib/NormalModule.js:192:16)
    at /Users/davidfox-powell/dev/frontend-boilerplate/node_modules/webpack/lib/NormalModule.js:160:10
    at /Users/davidfox-powell/dev/frontend-boilerplate/node_modules/loader-runner/lib/LoaderRunner.js:334:3
    at iterateNormalLoaders (/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/loader-runner/lib/LoaderRunner.js:182:10)
    at iterateNormalLoaders (/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/loader-runner/lib/LoaderRunner.js:189:10)
    at /Users/davidfox-powell/dev/frontend-boilerplate/node_modules/loader-runner/lib/LoaderRunner.js:204:3
    at Object.context.callback (/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/loader-runner/lib/LoaderRunner.js:87:13)
    at Object.module.exports (/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/babel-loader/index.js:89:8)
    at LOADER_EXECUTION (/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/loader-runner/lib/LoaderRunner.js:95:14)
    at runSyncOrAsync (/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/loader-runner/lib/LoaderRunner.js:96:4)
    at iterateNormalLoaders (/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/loader-runner/lib/LoaderRunner.js:200:2)
    at iterateNormalLoaders (/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/loader-runner/lib/LoaderRunner.js:189:10)
    at /Users/davidfox-powell/dev/frontend-boilerplate/node_modules/loader-runner/lib/LoaderRunner.js:204:3
    at Object.context.callback (/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/loader-runner/lib/LoaderRunner.js:87:13)
    at Object.module.exports (/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/eslint-loader/index.js:113:8)
    at LOADER_EXECUTION (/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/loader-runner/lib/LoaderRunner.js:95:14)
    at runSyncOrAsync (/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/loader-runner/lib/LoaderRunner.js:96:4)
    at iterateNormalLoaders (/Users/davidfox-powell/dev/frontend-boilerplate/node_modules/loader-runner/lib/LoaderRunner.js:200:2)
 @ multi main

[sokra]

I don't see a conflict here: ^2.4.0 and ^2.2.0 resolve both to the same version.

[dtothefp]

@sokra yeh I was thinking the same but I don't know what else would cause it or where to look for help? Any suggestions?

[sokra]

I updated the acorn version to ^3.0.0. Maybe this fixes the issue

[dtothefp]

@sokra I can confirm this fixes my issue when I installed the latest version from master. Any plans to make a new beta release soon?

[satya164]

Would love a new release!

[bgw]

This was because espree was monkey-patching acorn. This was fixed in espree: eslint/js#250

I can confirm that updating to espree 3.0.2 fixes this issue for me.

[bebraw]

Looks like the issue has been fixed based on webpack-contrib/eslint-loader#80. Closing.