Parser fails on certain files

Summary

I was trying to implement Stryker for one of our repos to see if it was easy to do. Sadly, I’ve had no luck so far. I ran into two issues: the first one is that the parser crashes on certain files. But the error stacktrace is not helpful (for an end user), because it starts and ends within the node modules.

This is the Stryker output for such an error:

$ stryker run
[2018-02-07 08:46:56.360] [INFO] ConfigReader - Using stryker.conf.js in the current working directory.
[2018-02-07 08:46:57.104] [INFO] InputFileResolver - Found 1 of 161 file(s) to be mutated.
[2018-02-07 08:46:57.105] [INFO] InitialTestExecutor - Starting initial test run. This may take a while.
[2018-02-07 08:46:57.106] [INFO] BabelConfigReader - Reading .babelrc file from path "/Users/ronderksen/Sites/blaze-wishlist-site-wehkamp/.babelrc"
[2018-02-07 08:47:13.505] [INFO] InitialTestExecutor - Initial test run succeeded. Ran 118 tests in 16 seconds.
[2018-02-07 08:47:13.509] [ERROR] StrykerCli - an error occurred { SyntaxError: Unexpected token (37:6)
    at Parser.pp$5.raise (/Users/ronderksen/Sites/blaze-wishlist-site-wehkamp/node_modules/babylon/lib/index.js:4454:13)
    at Parser.pp.unexpected (/Users/ronderksen/Sites/blaze-wishlist-site-wehkamp/node_modules/babylon/lib/index.js:1761:8)
    at Parser.pp$3.parseIdentifier (/Users/ronderksen/Sites/blaze-wishlist-site-wehkamp/node_modules/babylon/lib/index.js:4332:10)
    at Parser.pp$3.parsePropertyName (/Users/ronderksen/Sites/blaze-wishlist-site-wehkamp/node_modules/babylon/lib/index.js:4156:96)
    at Parser.parsePropertyName (/Users/ronderksen/Sites/blaze-wishlist-site-wehkamp/node_modules/babylon/lib/index.js:6229:23)
    at Parser.pp$3.parseObj (/Users/ronderksen/Sites/blaze-wishlist-site-wehkamp/node_modules/babylon/lib/index.js:4045:12)
    at Parser.pp$3.parseExprAtom (/Users/ronderksen/Sites/blaze-wishlist-site-wehkamp/node_modules/babylon/lib/index.js:3719:19)
    at Parser.parseExprAtom (/Users/ronderksen/Sites/blaze-wishlist-site-wehkamp/node_modules/babylon/lib/index.js:7238:22)
    at Parser.pp$3.parseExprSubscripts (/Users/ronderksen/Sites/blaze-wishlist-site-wehkamp/node_modules/babylon/lib/index.js:3494:19)
    at Parser.pp$3.parseMaybeUnary (/Users/ronderksen/Sites/blaze-wishlist-site-wehkamp/node_modules/babylon/lib/index.js:3474:19)
    at Parser.pp$3.parseExprOps (/Users/ronderksen/Sites/blaze-wishlist-site-wehkamp/node_modules/babylon/lib/index.js:3404:19)
    at Parser.pp$3.parseMaybeConditional (/Users/ronderksen/Sites/blaze-wishlist-site-wehkamp/node_modules/babylon/lib/index.js:3381:19)
    at Parser.pp$3.parseMaybeAssign (/Users/ronderksen/Sites/blaze-wishlist-site-wehkamp/node_modules/babylon/lib/index.js:3344:19)
    at Parser.parseMaybeAssign (/Users/ronderksen/Sites/blaze-wishlist-site-wehkamp/node_modules/babylon/lib/index.js:6474:20)
    at Parser.pp$3.parseParenAndDistinguishExpression (/Users/ronderksen/Sites/blaze-wishlist-site-wehkamp/node_modules/babylon/lib/index.js:3828:26)
    at Parser.pp$3.parseExprAtom (/Users/ronderksen/Sites/blaze-wishlist-site-wehkamp/node_modules/babylon/lib/index.js:3709:19) pos: 1631, loc: Position { line: 37, column: 6 } }

Stryker config

const path = require('path');

module.exports = function(config) {
  config.set({
    files: [
      {
        pattern: 'src/app/path/to/file.js',
        mutated: true,
        included: false,
      },
      'src/public/**/*',
      'src/app/**/*.scss',
      'src/app/**/path/to/file.spec.js',
      'src/app/**/path/to/file.spec.js.snap',
      'src/**/*',
      'test/*',
      'development/*',
    ],
    testRunner: 'jest',
    mutator: 'javascript',
    transpilers: ['babel'],
    reporter: ['html', 'clear-text', 'progress'],
    coverageAnalysis: 'off',
    babelrcFile: '.babelrc',
    jest: {
      config: require(path.resolve(__dirname, './test/jest.config.json')),
    },
  });
};

Stryker environment

├─┬ stryker@0.18.2
├─┬ stryker-api@0.12.0
├─┬ stryker-babel-transpiler@0.2.4
├─┬ stryker-html-reporter@0.11.5
├─┬ stryker-javascript-mutator@0.3.3
├─┬ stryker-jest-runner@0.4.0
├─┬ stryker-webpack-transpiler@0.1.2

Your Environment

software	version(s)
node	v8.9.4
npm	v.5.5.1
Operating System	macOS 10.13.2

[nicojs]

@ronderksen thanks for the clear reproduction steps. It seems that we don’t support the objectRestSpread yet. See list of plugins here: https://github.com/babel/babel/tree/master/packages/babylon#plugins

I will add it (and some more stage 1, 2 and 3 features) to the default list of plugins. At a later time we should make this part configurable.

[simondel]

Glad to hear that the problem has been solved! We usually reply to issues like these with a message which version of which plugin fixed the issue.

So you should have seen something like “This has been fixed with stryker-javascript-mutator 0.4.0” but we forgot that this time 😦

Thanks for creating a reproduction repo! Those really help us a lot 😃 If you need any more help, don’t hesitate to contact us!