[require-atomic-updates]: False positive on reused loop variable name

[fluggo]

Tell us about your environment

Environment Info:

Node version: v14.15.4
npm version: v7.5.3
Local ESLint version: v7.21.0 (Currently used)
Global ESLint version: Not found

Parser: @typescript-eslint/parser

Please show your full configuration:

Configuration

module.exports = {
  env: {
    es2020: true,
    node: true
  },
  root: true,
  parser: '@typescript-eslint/parser',
  parserOptions: {
    'project': './tsconfig.eslint.json',
    'sourceType': 'module',
    'tsconfigRootDir': __dirname,
  },
  plugins: [
    'eslint-plugin-import',
    '@typescript-eslint',
  ],
  extends: [
    'eslint:recommended',
    'plugin:@typescript-eslint/recommended',
    'plugin:@typescript-eslint/recommended-requiring-type-checking',
  ],
  rules: {
    '@typescript-eslint/no-non-null-assertion': 'warn',
    '@typescript-eslint/no-shadow': ['error', { 'hoist': 'all' }],
    '@typescript-eslint/no-unused-expressions': 'error',
    '@typescript-eslint/require-await': 'warn',
    '@typescript-eslint/require-array-sort-compare': 'error',
    '@typescript-eslint/no-base-to-string': 'error',
    '@typescript-eslint/restrict-plus-operands': 'error',
    'array-callback-return': 'error',
    'eqeqeq': ['error', 'always'],
    'guard-for-in': 'error',
    'no-bitwise': 'error',
    'no-caller': 'error',
    'no-eval': 'error',
    'no-new-wrappers': 'error',
    'no-template-curly-in-string': 'error',
    'no-throw-literal': 'error',
    'no-undef-init': 'error',
    'no-unreachable-loop': 'error',
    'no-useless-backreference': 'error',
    'no-var': 'error',
    'require-atomic-updates': 'error',
    'prefer-const': 'off',      // change to 'error'
    '@typescript-eslint/consistent-type-definitions': ['warn', 'interface'],
    '@typescript-eslint/semi': ['error', 'always'],
    '@typescript-eslint/unified-signatures': 'error',
    '@typescript-eslint/prefer-string-starts-ends-with': 'warn',
    '@typescript-eslint/no-extra-semi': 'off',        // change to 'warn'
    '@typescript-eslint/no-inferrable-types': 'off',    // change to ['warn', {ignoreParameters: true}]
    'arrow-body-style': 'off',          // change to ['error', 'as-needed'],
    '@typescript-eslint/no-explicit-any': 'off',
    '@typescript-eslint/explicit-module-boundary-types': 'off',
    '@typescript-eslint/no-unused-vars': 'off',
    '@typescript-eslint/no-empty-function': 'off',
    '@typescript-eslint/no-unsafe-assignment': 'off',
    '@typescript-eslint/no-unsafe-member-access': 'off',
    '@typescript-eslint/no-unsafe-call': 'off',
    '@typescript-eslint/no-unsafe-return': 'off',
    '@typescript-eslint/no-implicit-any-catch': 'off',
    '@typescript-eslint/restrict-template-expressions': 'off',
    '@typescript-eslint/no-unnecessary-condition': 'off',
    'no-inner-declarations': 'off',
    'no-promise-executor-return': 'off',
  }
};

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

async function foo(e) {
}

async function run() {
  const input = [];
  const props = [];

  for(const entry of input) {
    const prop = props.find(a => a.id === entry.id) || null;
    await foo(entry);
  }

  // Possible race condition: `const entry` might be reassigned based on an outdated value of `const entry`
  for(const entry of input) {
    const prop = props.find(a => a.id === entry.id) || null;
  }

  for(const entry2 of input) {
    const prop = props.find(a => a.id === entry2.id) || null;
  }
}

Command: npx eslint scripts/sample-require-atomic-updates.ts

What did you expect to happen?

Did not expect any errors because the entry variables in the two loops are independent.

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

ESLint seems to think that the variable captured in the second loop's arrow function closure is the entry variable from the first loop, and flags an error.

/......./scripts/sample-require-atomic-updates.ts
  14:3  error  Possible race condition: `const entry` might be reassigned based on an outdated value of `const entry`  require-atomic-updates

✖ 1 problem (1 error, 0 warnings)

[mdjermanovic]

Hi @fluggo, thanks for the issue!

I can reproduce this is our online demo, looks like a bug..

[patriscus]

I am currently working on a potential fix. I hope to create a PR within the next two days