test: add test case for the error message

JounQin · JounQin · commit 1e09f8bc4e81 · 2025-05-31T08:26:45.000+08:00
diff --git a/.eslintrc.cjs b/.eslintrc.cjs
@@ -1,155 +1,3 @@
 // ! This file is here for testing `no-unused-modules` rule for eslintrc
 
-const { version } = require('eslint/package.json')
-
-const noEslintrc = +version.split('.')[0] > 8
-
-const testCompiled = process.env.TEST_COMPILED === '1'
-
-/** @type {import('eslint').Linter.Config} */
-module.exports = {
-  root: true,
-  reportUnusedDisableDirectives: true,
-  extends: [
-    'eslint:recommended',
-    'plugin:@typescript-eslint/recommended',
-    'plugin:eslint-plugin/recommended',
-    testCompiled && 'plugin:import-x/recommended',
-    'plugin:json/recommended-legacy',
-    'plugin:mdx/recommended',
-    'plugin:n/recommended',
-    !noEslintrc && 'plugin:unicorn/recommended',
-    'plugin:yml/standard',
-    'plugin:yml/prettier',
-    'plugin:prettier/recommended',
-  ].filter(Boolean),
-  env: {
-    node: true,
-    es6: true,
-    es2017: true,
-  },
-  parserOptions: {
-    sourceType: 'module',
-    ecmaVersion: 2020,
-  },
-  rules: {
-    '@typescript-eslint/no-non-null-assertion': 'off',
-    '@typescript-eslint/no-require-imports': 'off',
-
-    'no-constant-condition': noEslintrc ? 'error' : 'off',
-
-    'eslint-plugin/consistent-output': ['error', 'always'],
-    'eslint-plugin/meta-property-ordering': 'error',
-    'eslint-plugin/no-deprecated-context-methods': 'error',
-    'eslint-plugin/no-deprecated-report-api': 'off',
-    'eslint-plugin/prefer-replace-text': 'error',
-    'eslint-plugin/report-message-format': 'error',
-    'eslint-plugin/require-meta-docs-description': [
-      'error',
-      { pattern: String.raw`^(Enforce|Ensure|Prefer|Forbid).+\.$` },
-    ],
-    'eslint-plugin/require-meta-schema': 'error',
-    'eslint-plugin/require-meta-type': 'error',
-    'n/no-extraneous-require': 'off',
-    'n/no-missing-import': 'off',
-    'n/no-missing-require': 'off',
-    'n/no-unsupported-features/es-syntax': 'off',
-    ...(noEslintrc || {
-      'unicorn/filename-case': [
-        'error',
-        {
-          case: 'kebabCase',
-          ignore: [String.raw`^(CONTRIBUTING|README)\.md$`],
-        },
-      ],
-    }),
-    'unicorn/no-array-callback-reference': 'off',
-    'unicorn/no-array-reduce': 'off',
-    'unicorn/no-null': 'off',
-    'unicorn/prefer-module': 'off',
-    'unicorn/prevent-abbreviations': 'off',
-    'unicorn/prefer-at': 'off',
-    'unicorn/prefer-export-from': ['error', { ignoreUsedVariables: true }],
-
-    // dog fooding
-    ...(testCompiled && {
-      'import-x/no-extraneous-dependencies': [
-        'error',
-        {
-          devDependencies: ['test/**'],
-          optionalDependencies: false,
-          peerDependencies: true,
-          bundledDependencies: false,
-        },
-      ],
-      'import-x/unambiguous': 'off',
-    }),
-  },
-
-  overrides: [
-    {
-      files: ['*.ts'],
-      excludedFiles: ['test/fixtures'],
-      rules: {
-        '@typescript-eslint/array-type': [
-          2,
-          {
-            default: 'array-simple',
-          },
-        ],
-        '@typescript-eslint/consistent-type-definitions': ['error', 'type'],
-        '@typescript-eslint/consistent-type-imports': [
-          'error',
-          {
-            fixStyle: 'inline-type-imports',
-          },
-        ],
-        '@typescript-eslint/no-unused-vars': [
-          'error',
-          {
-            argsIgnorePattern: '^_',
-            varsIgnorePattern: '^_',
-          },
-        ],
-        ...(testCompiled && {
-          'import-x/consistent-type-specifier-style': 'error',
-          'import-x/order': [
-            'error',
-            {
-              alphabetize: {
-                order: 'asc',
-              },
-              'newlines-between': 'always',
-            },
-          ],
-        }),
-      },
-      settings: {
-        'import-x/resolver': {
-          typescript: {
-            project: 'tsconfig.base.json',
-          },
-        },
-      },
-    },
-    {
-      files: 'test/**',
-      env: {
-        jest: true,
-      },
-    },
-    {
-      files: 'global.d.ts',
-      rules: {
-        'import-x/no-extraneous-dependencies': 'off',
-      },
-    },
-    {
-      files: 'README.md',
-      rules: {
-        // https://github.com/bmish/eslint-doc-generator/issues/655
-        'no-irregular-whitespace': 'off',
-      },
-    },
-  ],
-}
+module.exports = {}
diff --git a/docs/rules/no-unused-modules.md b/docs/rules/no-unused-modules.md
@@ -9,7 +9,7 @@ Reports:
 - dynamic imports are supported if argument is a literal string
 
 > [!IMPORTANT]
-> This rule is only compatible with legacy configs. If you make use of the new flat config, either do not enable this rule, or provide a legacy eslintrc config at the same time together for this rule to be functional.
+> This rule is only compatible with legacy configs. If you make use of the new flat config, either do not enable this rule, or provide a legacy eslintrc config (even empty) at the same time together for this rule to be functional.
 
 ## Rule Details
 
diff --git a/package.json b/package.json
@@ -119,6 +119,7 @@
     "@types/klaw-sync": "^6.0.5",
     "@types/node": "^22.15.27",
     "@types/pnpapi": "^0.0.5",
+    "@types/tmp": "^0.2.6",
     "@typescript-eslint/eslint-plugin": "^8.33.0",
     "@typescript-eslint/parser": "^8.33.0",
     "@typescript-eslint/rule-tester": "^8.33.0",
@@ -153,6 +154,7 @@
     "redux": "^5.0.1",
     "simple-git-hooks": "^2.13.0",
     "tinyexec": "^1.0.1",
+    "tmp": "^0.2.3",
     "ts-node": "^10.9.2",
     "tsdown": "^0.12.5",
     "type-fest": "^4.41.0",
diff --git a/src/rules/no-unused-modules.ts b/src/rules/no-unused-modules.ts
@@ -67,7 +67,7 @@ function listFilesUsingFileEnumerator(
     ) {
       throw new Error(`
 Due to the exclusion of certain internal ESLint APIs when using flat config,
-the import/no-unused-modules rule requires an .eslintrc file to know which
+the import-x/no-unused-modules rule requires an .eslintrc file (even empty) to know which
 files to ignore (even when using flat config).
 The .eslintrc file only needs to contain "ignorePatterns", or can be empty if
 you do not want to ignore any files.
diff --git a/test/fixtures/eslint-v9/.gitignore b/test/fixtures/eslint-v9/.gitignore
@@ -0,0 +1 @@
+node_modules
diff --git a/test/fixtures/eslint-v9/.npmrc b/test/fixtures/eslint-v9/.npmrc
@@ -0,0 +1 @@
+package-lock=false
diff --git a/test/fixtures/eslint-v9/eslint.config.mjs b/test/fixtures/eslint-v9/eslint.config.mjs
@@ -0,0 +1,22 @@
+import { importX } from 'eslint-plugin-import-x'
+import js from '@eslint/js'
+
+export default [
+  js.configs.recommended,
+  importX.flatConfigs.recommended,
+  {
+    files: ['**/*.{js,mjs,cjs}'],
+    languageOptions: {
+      ecmaVersion: 'latest',
+      sourceType: 'module',
+    },
+    ignores: ['eslint.config.mjs', 'node_modules/*'],
+    rules: {
+      'no-unused-vars': 'off',
+      'import-x/no-dynamic-require': 'warn',
+      'import-x/no-nodejs-modules': 'warn',
+      'import-x/no-unused-modules': ['warn', { unusedExports: true }],
+      'import-x/no-cycle': 'warn',
+    },
+  },
+]
diff --git a/test/fixtures/eslint-v9/package.json b/test/fixtures/eslint-v9/package.json
@@ -0,0 +1,14 @@
+{
+  "name": "eslint-v9",
+  "version": "1.0.0",
+  "type": "module",
+  "main": "index.js",
+  "scripts": {
+    "lint": "eslint src --report-unused-disable-directives"
+  },
+  "devDependencies": {
+    "@eslint/js": "^9.17.0",
+    "eslint": "^9.17.0",
+    "eslint-plugin-import-x": "file:../../.."
+  }
+}
diff --git a/test/fixtures/eslint-v9/src/depth-zero.js b/test/fixtures/eslint-v9/src/depth-zero.js
@@ -0,0 +1,3 @@
+import { foo } from './es6/depth-one-dynamic'
+
+foo()
diff --git a/test/fixtures/eslint-v9/src/exports.js b/test/fixtures/eslint-v9/src/exports.js
@@ -0,0 +1,6 @@
+//import c from './exports';
+import { a, b } from './exports'
+
+import path from 'path'
+import fs from 'node:fs'
+import console from 'console'
diff --git a/test/rules/no-unused-modules.spec.ts b/test/rules/no-unused-modules.spec.ts
@@ -1,3 +1,5 @@
+import { execSync } from 'node:child_process'
+import type { ChildProcess } from 'node:child_process'
 import fs from 'node:fs'
 
 import { jest } from '@jest/globals'
@@ -7,8 +9,14 @@ import type { TSESLint } from '@typescript-eslint/utils'
 // eslint-disable-next-line import-x/default -- incorrect types
 import eslint8UnsupportedApi from 'eslint8.56/use-at-your-own-risk'
 import { RuleTester as ESLint9_FlatRuleTester } from 'eslint9'
+import { dirSync } from 'tmp'
 
-import { createRuleTestCaseFunctions, testFilePath, parsers } from '../utils.js'
+import {
+  createRuleTestCaseFunctions,
+  testFilePath,
+  parsers,
+  isESLint9,
+} from '../utils.js'
 import type { GetRuleModuleOptions, GetRuleModuleMessageIds } from '../utils.js'
 
 import { cjsRequire as require } from 'eslint-plugin-import-x'
@@ -1560,3 +1568,40 @@ for (const [name, FlatRuleTester] of [
     })
   })
 }
+
+;(isESLint9 ? describe : describe.skip)('with eslint 9+', () => {
+  it('provides meaningful error when eslintrc is not present', () => {
+    // Create temp directory outside of project root
+    const { name: tempDir, removeCallback } = dirSync({
+      unsafeCleanup: true,
+    })
+
+    // Copy example project to temp directory
+    // eslint-disable-next-line n/no-unsupported-features/node-builtins -- false positive
+    fs.cpSync(testFilePath('eslint-v9'), tempDir, {
+      recursive: true,
+    })
+
+    let errorMessage = ''
+
+    // We run `test-compiled` first, so that the plugin is already built
+    // But don't forget to run `yarn build` first if you're developing the rule or test case
+
+    // Install the plugin and run the lint command in the temp directory
+    try {
+      execSync(`npm install -D ${process.cwd()} && npm run lint`, {
+        cwd: tempDir,
+      })
+    } catch (error) {
+      errorMessage = (error as ChildProcess).stderr!.toString()
+    }
+
+    // Verify that the error message is as expected
+    expect(errorMessage).toContain(
+      'the import-x/no-unused-modules rule requires an .eslintrc file (even empty)',
+    )
+
+    // Cleanup
+    removeCallback()
+  }, 100_000)
+})
diff --git a/test/utils.ts b/test/utils.ts
@@ -6,6 +6,7 @@ import type {
   RunTests as TSESLintRunTests,
 } from '@typescript-eslint/rule-tester'
 import type { RuleModule } from '@typescript-eslint/utils/ts-eslint'
+import eslintPkg from 'eslint/package.json'
 import * as semver from 'semver'
 import typescriptPkg from 'typescript/package.json'
 
@@ -22,6 +23,8 @@ export const parsers = {
   HERMES: require.resolve('hermes-eslint'),
 }
 
+export const isESLint9 = semver.satisfies(eslintPkg.version, '>=9')
+
 export function tsVersionSatisfies(specifier: string) {
   return semver.satisfies(typescriptPkg.version, specifier)
 }
diff --git a/yarn.lock b/yarn.lock
@@ -3913,6 +3913,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@types/tmp@npm:^0.2.6":
+  version: 0.2.6
+  resolution: "@types/tmp@npm:0.2.6"
+  checksum: 10c0/a11bfa2cd8eaa6c5d62f62a3569192d7a2c28efdc5c17af0b0551db85816b2afc8156f3ca15ac76f0b142ae1403f04f44279871424233a1f3390b2e5fc828cd0
+  languageName: node
+  linkType: hard
+
 "@types/treeify@npm:^1.0.0":
   version: 1.0.3
   resolution: "@types/treeify@npm:1.0.3"
@@ -5951,6 +5958,7 @@ __metadata:
     "@types/klaw-sync": "npm:^6.0.5"
     "@types/node": "npm:^22.15.27"
     "@types/pnpapi": "npm:^0.0.5"
+    "@types/tmp": "npm:^0.2.6"
     "@typescript-eslint/eslint-plugin": "npm:^8.33.0"
     "@typescript-eslint/parser": "npm:^8.33.0"
     "@typescript-eslint/rule-tester": "npm:^8.33.0"
@@ -5993,6 +6001,7 @@ __metadata:
     simple-git-hooks: "npm:^2.13.0"
     stable-hash: "npm:^0.0.5"
     tinyexec: "npm:^1.0.1"
+    tmp: "npm:^0.2.3"
     ts-node: "npm:^10.9.2"
     tsdown: "npm:^0.12.5"
     type-fest: "npm:^4.41.0"
@@ -12348,6 +12357,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"tmp@npm:^0.2.3":
+  version: 0.2.3
+  resolution: "tmp@npm:0.2.3"
+  checksum: 10c0/3e809d9c2f46817475b452725c2aaa5d11985cf18d32a7a970ff25b568438e2c076c2e8609224feef3b7923fa9749b74428e3e634f6b8e520c534eef2fd24125
+  languageName: node
+  linkType: hard
+
 "tmpl@npm:1.0.5":
   version: 1.0.5
   resolution: "tmpl@npm:1.0.5"

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+import { foo } from './es6/depth-one-dynamic'`
	`2`	`+`
	`3`	`+foo()`