babel: error index.js: "" is not a valid identifer name error with 7.7.0

Bug Report

Hi There, One of our builds on CI has just failed when we picked up the latest 7.7.0 release. Building a react-native project is failing and we’re getting this error :

error index.js: "" is not a valid identifer name
debug TypeError: "" is not a valid identifer name
    at node_modules/metro/node_modules/@babel/types/lib/definitions/core.js:322:17
    at Object.validate (node_modules/@babel/types/lib/definitions/utils.js:201:7)
    at validateField (node_modules/metro/node_modules/@babel/types/lib/validators/validate.js:22:9)
    at validate (node_modules/metro/node_modules/@babel/types/lib/validators/validate.js:16:3)
    at builder (node_modules/metro/node_modules/@babel/types/lib/builders/builder.js:38:27)
    at Object.Identifier (node_modules/metro/node_modules/@babel/types/lib/builders/generated/index.js:334:31)
    at functionFromProgram (metro/src/ModuleGraph/worker/JsFileWrapping.js:71:7)
    at Object.wrapModule (metro/src/ModuleGraph/worker/JsFileWrapping.js:39:19)
    at node_modules/metro/src/JSTransformer/worker.js:323:52

This happend on circle CI right after 7.7.0 was published, on a code base that hasn’t changed, and is building perfectly on other platforms where the dependencies haven’t been installed.

The problem is that many packages (like the metro bundler) have @babel/core@^7.0.0 defined as dependency, so this is automatically picked up when using these dependencies. This is what happened to us this morning

Current Behavior I expect my RN bundle to build 😬

Input Code simply make sure 7.7.0 is resolved. if 7.6.3 or earlier is resolved, all is good

Environment

Babel version(s): [7.7.0]
Node/npm version: [Node 8]
OS: [Ubuntu]
Monorepo: [no]
How you are using Babel: [react native metro bundler]

Possible Solution remove that update

About this issue

Original URL
State: closed
Created 5 years ago
Reactions: 12
Comments: 19 (4 by maintainers)

Most upvoted comments

FYI, react native community is deeply affected by this.

yuanfux on Nov 5, 2019

Definitely an unfortunate Metro bug: https://github.com/facebook/metro/blob/690f175c2d88432521edd9cde55bfdd220588134/packages/metro/src/ModuleGraph/worker/JsFileWrapping.js#L81

An empty string is not a valid variable name and isn’t a valid function name 😦 They should just be passing null, e.g.

  return t.functionExpression(
    null,
    parameters.map(makeIdentifier),
    t.blockStatement(program.body, program.directives),
  );

Tracked in https://github.com/facebook/metro/issues/481

loganfsmyth on Nov 5, 2019

@guyca besides, if you have to rollback for a feature to work, it means there’s a breaking change in the version, and it shouldn’t be 7.7.0 but 8.0.0 and we wouldn’t have that problem @nicolo-ribaudo this is really serious. Could you please - at least consider to - unpublish that version so it doesn’t block people from building react-native bundles ?

francois-codes on Nov 5, 2019

@f-roland Yep! My intention was only to provide context, not to argue against reverting this change.

loganfsmyth on Nov 5, 2019

Thanks @yuanfux - still waiting for the versions to be removed from the npm registry - that’s the only real fix

francois-codes on Nov 5, 2019