babel: [Bug] plugin-transform-block-scoping: Cannot read property 'bindings' of null

Choose one: is this a bug report or feature request?

Log:

james@LAPTOP-UP0DKQSC ~/code/winescan/Stopwatch
$ yarn test
yarn run v1.5.1
$ jest
FAIL __tests__\App.js
  ● Test suite failed to run

    TypeError: Cannot read property 'bindings' of null

      at Scope.moveBindingTo (node_modules/@babel/traverse/lib/scope/index.js:923:13)
      at BlockScoping.updateScopeInfo (node_modules/babel-plugin-transform-es2015-block-scoping/lib/index.js:364:17)
      at BlockScoping.run (node_modules/babel-plugin-transform-es2015-block-scoping/lib/index.js:330:12)
      at PluginPass.BlockStatementSwitchStatementProgram (node_modules/babel-plugin-transform-es2015-block-scoping/lib/index.js:70:24)
      at newFn (node_modules/@babel/traverse/lib/visitors.js:223:21)
      at NodePath._call (node_modules/@babel/traverse/lib/path/context.js:64:19)
      at NodePath.call (node_modules/@babel/traverse/lib/path/context.js:38:17)
      at NodePath.visit (node_modules/@babel/traverse/lib/path/context.js:99:12)
      at TraversalContext.visitQueue (node_modules/@babel/traverse/lib/context.js:135:18)
      at TraversalContext.visitSingle (node_modules/@babel/traverse/lib/context.js:94:19)

Input Code

import 'react-native';
import React from 'react';
import App from '../App';

// Note: test renderer must be required after react-native.
import renderer from 'react-test-renderer';

it('renders correctly', () => {
  const tree = renderer.create(<App />).toJSON();
  expect(tree).toMatchSnapshot();
});

Babel/Babylon Configuration (.babelrc, package.json, cli command)

{
  "presets": ["react-native"]
}

Possible Solution

I did a bit of manual digging through the code. The problem is that here, parentScope is null. parentScope is initialized here. Over here, where updateScopeInfo was called, we make some checks before calling the method to ensure that the parent is a function/program node.

It seems like the code in the last URL should be changed:

     // this is a block within a `Function/Program` so we can safely leave it be
-    if (t.isFunction(this.parent) || t.isProgram(this.block)) {
+    if (t.isFunction(this.parent) || t.isProgram(this.parent)) {

About this issue

Original URL
State: closed
Created 6 years ago
Comments: 28 (14 by maintainers)

Most upvoted comments

Hey @jamesqo! We really appreciate you taking the time to report an issue. The collaborators on this project attempt to help as many people as possible, but we’re a limited number of volunteers, so it’s possible this won’t be addressed swiftly.

If you need any help, or just have general Babel or JavaScript questions, we have a vibrant Slack community that typically always has someone willing to help. You can sign-up here for an invite.

+30

babel-bot on Mar 25, 2018

@Tauka you’ll want to use @babel/preset-env (env, which is babel-preset-env will load the old v6 versions)

+12

existentialism on Apr 25, 2018

Here’s a one liner to reproduce the issue.

Running with 7.0.0-beta.44:

require('@babel/core').transform('let a', { filename: 'test.js', presets: ['react-native'] });

produces:

./node_modules/@babel/traverse/lib/scope/index.js:964
      scope.bindings[name] = info;
            ^

TypeError: Cannot read property 'bindings' of null
    at Scope.moveBindingTo (./node_modules/@babel/traverse/lib/scope/index.js:964:13)
    at BlockScoping.updateScopeInfo (./node_modules/babel-plugin-transform-es2015-block-scoping/lib/index.js:364:17)
    at BlockScoping.run (./node_modules/babel-plugin-transform-es2015-block-scoping/lib/index.js:330:12)
    at PluginPass.BlockStatementSwitchStatementProgram (./node_modules/babel-plugin-transform-es2015-block-scoping/lib/index.js:70:24)
    at newFn (./node_modules/@babel/traverse/lib/visitors.js:243:21)
    at NodePath._call (./node_modules/@babel/traverse/lib/path/context.js:65:18)
    at NodePath.call (./node_modules/@babel/traverse/lib/path/context.js:40:17)
    at NodePath.visit (./node_modules/@babel/traverse/lib/path/context.js:100:12)
    at TraversalContext.visitQueue (./node_modules/@babel/traverse/lib/context.js:144:16)
    at TraversalContext.visitSingle (./node_modules/@babel/traverse/lib/context.js:104:19)

ArtemGovorov on Apr 9, 2018

@ArtemGovorov your stack trace also hints at mixing v7 and v6:

at Scope.moveBindingTo (./node_modules/@babel/traverse/lib/scope/index.js:964:13)

and

at BlockScoping.updateScopeInfo (./node_modules/babel-plugin-transform-es2015-block-scoping/lib/index.js:364:17)

(Note the things in bold)

existentialism on Apr 9, 2018

@existentialism Problem solved, thank you!

Tauka on Apr 28, 2018

@existentialism Thanks for your help! I have solved this issue a few days ago, and I can finally link to github today…… this is my suggestions:

Replace babel-preset-es2015 with @babel/preset-env
Try to update all of your babel plugins to babel 7 and make sure they have the same version
If you used babel-preset-react-native, try to update your plugins to 7.0.0-beta.47
If you have some problem with babel-core@7.X.X, you can try to install babel-core@7.0.0-bridge.0 Thanks for all of your help!

sxyshirly on Aug 2, 2018