[Fix] no-unused-modules: fix usage of import/extensions settings

CHANGELOG.md

@@ -5,6 +5,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 This change log adheres to standards from [Keep a CHANGELOG](http://keepachangelog.com).
 
 ## [Unreleased]
+### Fixed
+- [`no-unused-modules`]: fix usage of `import/extensions` settings ([#1560], thanks [@stekycz])
 
 ## [2.19.1] - 2019-12-08
 ### Fixed
@@ -620,6 +622,7 @@ for info on changes for earlier releases.
 
 [`memo-parser`]: ./memo-parser/README.md
 
+[#1560]: https://github.com/benmosher/eslint-plugin-import/pull/1560
 [#1551]: https://github.com/benmosher/eslint-plugin-import/pull/1551
 [#1542]: https://github.com/benmosher/eslint-plugin-import/pull/1542
 [#1521]: https://github.com/benmosher/eslint-plugin-import/pull/1521
@@ -1038,3 +1041,4 @@ for info on changes for earlier releases.
 [@christophercurrie]: https://github.com/christophercurrie
 [@randallreedjr]: https://github.com/randallreedjr
 [@Pessimistress]: https://github.com/Pessimistress
+[@stekycz]: https://github.com/stekycz

src/rules/no-unused-modules.js

@@ -5,6 +5,7 @@
  */
 
 import Exports from '../ExportMap'
+import { getFileExtensions } from 'eslint-module-utils/ignore'
 import resolve from 'eslint-module-utils/resolve'
 import docsUrl from '../docsUrl'
 import { dirname, join } from 'path'
@@ -16,19 +17,28 @@ import includes from 'array-includes'
 // and has been moved to eslint/lib/cli-engine/file-enumerator in version 6
 let listFilesToProcess
 try {
-  var FileEnumerator = require('eslint/lib/cli-engine/file-enumerator').FileEnumerator
-  listFilesToProcess = function (src) {
-    var e = new FileEnumerator()
+  const FileEnumerator = require('eslint/lib/cli-engine/file-enumerator').FileEnumerator
+  listFilesToProcess = function (src, extensions) {
+    const e = new FileEnumerator({
+      extensions: extensions,
+    })
     return Array.from(e.iterateFiles(src), ({ filePath, ignored }) => ({
       ignored,
       filename: filePath,
     }))
   }
 } catch (e1) {
+  let originalListFilesToProcess
   try {
-    listFilesToProcess = require('eslint/lib/util/glob-utils').listFilesToProcess
+    originalListFilesToProcess = require('eslint/lib/util/glob-utils').listFilesToProcess
   } catch (e2) {
-    listFilesToProcess = require('eslint/lib/util/glob-util').listFilesToProcess
+    originalListFilesToProcess = require('eslint/lib/util/glob-util').listFilesToProcess
+  }
+  // Prevent passing invalid options (extensions array) to old versions of the function.
+  // https://github.com/eslint/eslint/blob/v5.16.0/lib/util/glob-utils.js#L178-L280
+  // https://github.com/eslint/eslint/blob/v5.2.0/lib/util/glob-util.js#L174-L269
+  listFilesToProcess = function (src) {
+    return originalListFilesToProcess(src)
   }
 }
 
@@ -44,7 +54,6 @@ const CLASS_DECLARATION = 'ClassDeclaration'
 const DEFAULT = 'default'
 const TYPE_ALIAS = 'TypeAlias'
 
-let preparationDone = false
 const importList = new Map()
 const exportList = new Map()
 const ignoredFiles = new Set()
@@ -59,12 +68,14 @@ const isNodeModule = path => {
  *
  * return all files matching src pattern, which are not matching the ignoreExports pattern
  */
-const resolveFiles = (src, ignoreExports) => {
+const resolveFiles = (src, ignoreExports, context) => {
+  const extensions = Array.from(getFileExtensions(context.settings))
+
   const srcFiles = new Set()
-  const srcFileList = listFilesToProcess(src)
+  const srcFileList = listFilesToProcess(src, extensions)
 
   // prepare list of ignored files
-  const ignoredFilesList =  listFilesToProcess(ignoreExports)
+  const ignoredFilesList =  listFilesToProcess(ignoreExports, extensions)
   ignoredFilesList.forEach(({ filename }) => ignoredFiles.add(filename))
 
   // prepare list of source files, don't consider files from node_modules
@@ -200,11 +211,26 @@ const getSrc = src => {
  * the start of a new eslint run
  */
 let srcFiles
+let lastPrepareKey
 const doPreparation = (src, ignoreExports, context) => {
-  srcFiles = resolveFiles(getSrc(src), ignoreExports)
+  const prepareKey = JSON.stringify({
+    src: (src || []).sort(),
+    ignoreExports: (ignoreExports || []).sort(),
+    extensions: Array.from(getFileExtensions(context.settings)).sort(),
+  })
+  if (prepareKey === lastPrepareKey) {
+    return
+  }
+
+  importList.clear()
+  exportList.clear()
+  ignoredFiles.clear()
+  filesOutsideSrc.clear()
+
+  srcFiles = resolveFiles(getSrc(src), ignoreExports, context)
   prepareImportsAndExports(srcFiles, context)
   determineUsage()
-  preparationDone = true
+  lastPrepareKey = prepareKey
 }
 
 const newNamespaceImportExists = specifiers =>
@@ -340,7 +366,7 @@ module.exports = {
       unusedExports,
     } = context.options[0] || {}
 
-    if (unusedExports && !preparationDone) {
+    if (unusedExports) {
       doPreparation(src, ignoreExports, context)
     }
 
@@ -389,7 +415,7 @@ module.exports = {
 
       // make sure file to be linted is included in source files
       if (!srcFiles.has(file)) {
-        srcFiles = resolveFiles(getSrc(src), ignoreExports)
+        srcFiles = resolveFiles(getSrc(src), ignoreExports, context)
         if (!srcFiles.has(file)) {
           filesOutsideSrc.add(file)
           return

tests/files/no-unused-modules/jsx/file-jsx-a.jsx

@@ -0,0 +1,3 @@
+import {b} from './file-jsx-b';
+
+export const a = b + 1;

tests/files/no-unused-modules/jsx/file-jsx-b.jsx

@@ -0,0 +1 @@
+export const b = 2;

tests/files/no-unused-modules/typescript/file-ts-a.ts

@@ -0,0 +1,3 @@
+import {b} from './file-ts-b';
+
+export const a = b + 1;

tests/files/no-unused-modules/typescript/file-ts-b.ts

@@ -0,0 +1 @@
+export const b = 2;

tests/src/rules/no-unused-modules.js

@@ -1,9 +1,13 @@
 import { test, testFilePath } from '../utils'
+import jsxConfig from '../../../config/react'
+import typescriptConfig from '../../../config/typescript'
 
 import { RuleTester } from 'eslint'
 import fs from 'fs'
 
 const ruleTester = new RuleTester()
+    , typescriptRuleTester = new RuleTester(typescriptConfig)
+    , jsxRuleTester = new RuleTester(jsxConfig)
     , rule = require('rules/no-unused-modules')
 
 const error = message => ({ ruleId: 'no-unused-modules', message })
@@ -18,6 +22,18 @@ const unusedExportsOptions = [{
   ignoreExports: [testFilePath('./no-unused-modules/*ignored*.js')],
 }]
 
+const unusedExportsTypescriptOptions = [{
+  unusedExports: true,
+  src: [testFilePath('./no-unused-modules/typescript')],
+  ignoreExports: undefined,
+}]
+
+const unusedExportsJsxOptions = [{
+  unusedExports: true,
+  src: [testFilePath('./no-unused-modules/jsx')],
+  ignoreExports: undefined,
+}]
+
 // tests for missing exports
 ruleTester.run('no-unused-modules', rule, {
   valid: [
@@ -686,3 +702,51 @@ describe('Avoid errors if re-export all from umd compiled library', () => {
     invalid: [],
   })
 })
+
+describe('correctly work with Typescript only files', () => {
+  typescriptRuleTester.run('no-unused-modules', rule, {
+    valid: [
+      test({
+        options: unusedExportsTypescriptOptions,
+        code: 'import a from "file-ts-a";',
+        parser: require.resolve('@typescript-eslint/parser'),
+        filename: testFilePath('./no-unused-modules/typescript/file-ts-a.ts'),
+      }),
+    ],
+    invalid: [
+      test({
+        options: unusedExportsTypescriptOptions,
+        code: `export const b = 2;`,
+        parser: require.resolve('@typescript-eslint/parser'),
+        filename: testFilePath('./no-unused-modules/typescript/file-ts-b.ts'),
+        errors: [
+          error(`exported declaration 'b' not used within other modules`),
+        ],
+      }),
+    ],
+  })
+})
+
+describe('correctly work with JSX only files', () => {
+  jsxRuleTester.run('no-unused-modules', rule, {
+    valid: [
+      test({
+        options: unusedExportsJsxOptions,
+        code: 'import a from "file-jsx-a";',
+        parser: require.resolve('babel-eslint'),
+        filename: testFilePath('./no-unused-modules/jsx/file-jsx-a.jsx'),
+      }),
+    ],
+    invalid: [
+      test({
+        options: unusedExportsJsxOptions,
+        code: `export const b = 2;`,
+        parser: require.resolve('babel-eslint'),
+        filename: testFilePath('./no-unused-modules/jsx/file-jsx-b.jsx'),
+        errors: [
+          error(`exported declaration 'b' not used within other modules`),
+        ],
+      }),
+    ],
+  })
+})