Missing module error with the babelification

[sindresorhus]

@floatdrop after 1d5ef4c landed I'm now getting this error when testing got using master.

~/dev/got master
❯ ava

module.js:339
    throw err;
    ^

Error: Cannot find module 'babel-runtime/helpers/async-to-generator'
    at Function.Module._resolveFilename (module.js:337:15)
    at Function.Module._load (module.js:287:25)
    at Module.require (module.js:366:17)
    at require (module.js:385:17)
    at Object.<anonymous> (/Users/sindresorhus/dev/got/test/unix-socket.js:3:25)
    at Module._compile (module.js:435:26)
    at requireFromString (/Users/sindresorhus/dev/ava/node_modules/require-from-string/index.js:14:4)
    at Object.<anonymous> (/Users/sindresorhus/dev/ava/lib/babel.js:28:1)
    at Module._compile (module.js:435:26)
    at Object.Module._extensions..js (module.js:442:10)
module.js:339
    throw err;
    ^

Error: Cannot find module 'babel-runtime/helpers/async-to-generator'
    at Function.Module._resolveFilename (module.js:337:15)
    at Function.Module._load (module.js:287:25)
    at Module.require (module.js:366:17)
    at require (module.js:385:17)
    at Object.<anonymous> (/Users/sindresorhus/dev/got/test/retry.js:3:25)
    at Module._compile (module.js:435:26)
    at requireFromString (/Users/sindresorhus/dev/ava/node_modules/require-from-string/index.js:14:4)
    at Object.<anonymous> (/Users/sindresorhus/dev/ava/lib/babel.js:28:1)
    at Module._compile (module.js:435:26)
    at Object.Module._extensions..js (module.js:442:10)
TypeError: Cannot read property 'stack' of undefined
    at error (/Users/sindresorhus/dev/ava/cli.js:51:19)
From previous event:
    at Object.<anonymous> (/Users/sindresorhus/dev/ava/cli.js:218:34)
    at Module._compile (module.js:435:26)
    at Object.Module._extensions..js (module.js:442:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:311:12)
    at Function.Module.runMain (module.js:467:10)
    at startup (node.js:134:18)
    at node.js:961:3

[floatdrop]

@sindresorhus babel transpile files with async and prepends

var _asyncToGenerator = require('babel-runtime/helpers/async-to-generator')['default'];

At the top, but in module.paths of test there is no babel-runtime module:

Module {
  id: '/Users/floatdrop/github.com/got/test/unix-socket.js',
  exports: {},
  parent:
   Module {
     id: '/Users/floatdrop/github.com/got/node_modules/ava/node_modules/require-from-string/index.js',
     exports: [Function: requireFromString],
     parent:
      Module {
        id: '.',
        exports: {},
        parent: null,
        filename: '/Users/floatdrop/github.com/got/node_modules/ava/lib/babel.js',
        loaded: false,
        children: [Object],
        paths: [Object] },
     filename: '/Users/floatdrop/github.com/got/node_modules/ava/node_modules/require-from-string/index.js',
     loaded: true,
     children: [ [Circular] ],
     paths:
      [ '/Users/floatdrop/github.com/got/node_modules/ava/node_modules/require-from-string/node_modules',
        '/Users/floatdrop/github.com/got/node_modules/ava/node_modules',
        '/Users/floatdrop/github.com/got/node_modules',
        '/Users/floatdrop/github.com/node_modules',
        '/Users/floatdrop/node_modules',
        '/Users/node_modules',
        '/node_modules' ] },
  filename: '/Users/floatdrop/github.com/got/test/unix-socket.js',
  loaded: false,
  children: [],
  paths:
   [ '/Users/floatdrop/github.com/got/test/node_modules',
     '/Users/floatdrop/github.com/got/node_modules',
     '/Users/floatdrop/github.com/node_modules',
     '/Users/floatdrop/node_modules',
     '/Users/node_modules',
     '/node_modules' ] }

It looks like we should add some paths to paths property, but Node.js behaves the same way. Will look further in require hook for solution.

[floatdrop]

Removing runtime from optional helps (but it breaks Node.js 0.10.x).

[floatdrop]

So including runtime into optional makes Babel place require at the top. Removing it will work for Node.js with generators.

For Node.js 0.10.x we need regenerator runtime, which is depends on global Promise - facebook/regenerator#142 (like co). Babel includes regenerator runtime + core.js polyfills, when used with babel-core/register.

We could append regenerator runtime before test code, but if we append Promise polyfill - it will leak into test code scope, which is bad (but not in module which is good). Or make Promise local to regenerator with function wrapping.

@sindresorhus wdyt?

[sindresorhus]

Or make Promise local to regenerator with function wrapping.

This sounds like the best solution, but I would say we go with the fastest solution now. We can do it properly later. This issue is blocking AVA 0.4.0, so would be nice to get it fixed as fast as possible.

[sindresorhus]

core.js polyfills

Are we including this now? If not, that's a regression too.

[jamestalmage]

Simply installing babel-runtime locally fixed.

It seems to me the requireFromString line is causing the error.

requires in the transpiled code are trying to resolve from the wrong directory to get access to babel-runtime. The resolution is happening from the base directory, but the runtime is in ./node_modules/ava/node_modules/babel-runtime, which won't resolve.

It should be possible to use derequire to change all the require(...) to ___uniquederquirename__ in the transpiled code to else, then prefix the generated code with:

function ___uniquederequirename___(path) {
   try {
      return require(path);
   } catch (e) {
       if (/^babel/.test(path)) {
          // resolve from ava's root directory
       }  else {
           throw e;
       }
   }
}

[floatdrop]

Are we including this now? If not, that's a regression too.

@sindresorhus all polyfills now excluded from tests, because they affect tested code. I guess fastest way is to revet this commit and use babel/register.

@jamestalmage resolution is happening in right directory, but yes, there is no babel-runtime around, so we either need to append parts of it to code (regenerator and Promise).

[sindresorhus]

all polyfills now excluded from tests, because they affect tested code

With Babel 6 we can use https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-runtime, right?

Externalise references to helpers and builtins, automatically polyfilling your code without polluting globals

[sindresorhus]

Actually, in the Babel 5 docs, it says that the runtime plugin does not pollute globals:

Basically, you can use built-ins such as Promise, Set, Symbol etc as well use all the Babel features that require a polyfill seamlessly, without global pollution, making it extremely suitable for libraries.

https://github.com/babel/babel.github.io/blob/862b43db93e48762671267034a50c30c00e433e2/docs/usage/runtime.md

[floatdrop]

@sindresorhus then it is worth to workaround require somehow:

• install babel-runtime as peer-dependency
• hack on m.paths in require-from-string
• replace runtime require path with resolved one