eslint 6.2.0 unexpected token = and /

My environment

$ uname -a
Darwin foo.baz 18.7.0 Darwin Kernel Version 18.7.0: Thu Jun 20 18:42:21 PDT 2019; root:xnu-4903.270.47~4/RELEASE_X86_64 x86_64

• ESLint Version: 6.2.0

$ cat package.json | jq '.devDependencies.eslint'
"^6.2.0"
$ cat node_modules/eslint/package.json | jq '.version'
"6.2.0"

• Node Version: 12.8.1

$ node --version
v12.8.1

• npm Version: 6.10.3

$ npm --version
6.10.3

Please show your full configuration:

$ cat .eslintrc.js

module.exports = {
  env: {
    browser: true,
    es6:     true,
    node:    true,
    jest:    true,
  },
  extends: [
    "eslint:recommended",
    "plugin:react/recommended",
    "plugin:jest/recommended",
    "plugin:jsx-a11y/recommended"
  ],
  parserOptions: {
    ecmaFeatures: {
      jsx: true
    },
    ecmaVersion: "2018",
    sourceType:  "module",
  },
  plugins: [
    "react",
    "jest",
    "jsx-a11y"
  ],
  rules: {
    indent: [
      "error",
      2
    ],
    "linebreak-style": [
      "error",
      "unix"
    ],
    quotes: [
      "error",
      "double"
    ],
    semi: [
      "error",
      "always"
    ],
    "key-spacing": [
      "error",
      {align: "value"}
    ],
    "no-console":           "off",
    "no-debugger":          "warn",
    "no-alert":             "warn",
    "object-curly-spacing": [
      "error",
      "never"
    ],
    "array-bracket-spacing": [
      "error",
      "never"
    ]
  },
  overrides: [
    {
      files: ["*.test.js"],
      rules: {
        "react/no-find-dom-node": "off"
      }
    }
  ],
  settings: {
    react: {
      version: "detect"
    }
  }
};

What did you do? Please include the actual source code causing the issue, as well as the command that you used to run ESLint.

$ cat src/components/App/App.js

"use strict";

import React from "react";

class App extends React.Component {
  render() {
    return (
      <div id="container">
        <p>
          hello internet!
        </p>
      </div>
    );
  }
}

export default App;

$ cat src/index.js

"use strict";

import React from "react";
import ReactDOM from "react-dom";
import App from "./components/App/App";

ReactDOM.render(
  <App />,
  document.getElementById("root")
);

$ npx eslint src/**/**.js

What did you expect to happen? that all linting will pass. when running eslint@6.1.0, it passes fine. when running eslint@6.2.0 it fails as above.

What actually happened? Please include the actual, raw output from ESLint.

$ npx eslint src/**/**.js

/Users/foo/react/src/components/App/App.js
  8:14  error  Parsing error: Unexpected token =

/Users/foo/react/src/index.js
  8:8  error  Parsing error: Unexpected token /

✖ 2 problems (2 errors, 0 warnings)

[mysticatea]

Webpack and Rollup have the same problem.

If this is not a bug of npm then this is the problem in Acorn. This problem appears when two Acorns are different entities: (1) Acorn that plugins loaded, (2) Acorn that is using the plugins. If Acorn did pass self token type objects to plugins, this problem will disappear.

[SimenB]

espree depends on acorn@7 and acorn-jsx@5 - however acorn-jsx@5 has a peer dependency on acorn@6. Yarn also prints a warning, but it doesn’t fail at runtime.

warning "eslint > espree > acorn-jsx@5.0.1" has incorrect peer dependency "acorn@^6.0.0".

https://github.com/eslint/espree/blob/c0635bac4cd891cb612fb81655012e2579f4e2b1/package.json#L21-L22 https://github.com/RReverser/acorn-jsx/blob/6697d3407221a58e23d040b4059f20eb045247a5/package.json#L21-L26

Should just be a warning though, no? Might be worth PR-ing acorn-jsx allowing v7 of acorn. https://github.com/acornjs/acorn/blob/aedbc56b86c086fcbee3214a6516f59794c2a99c/acorn/CHANGELOG.md#700-2019-08-13