feat: support ESLint 8.x

Author: MichaelDeBoey

.github/workflows/node.yml

@@ -25,6 +25,7 @@ jobs:
       matrix:
         node-version: ${{ fromJson(needs.matrix.outputs.majors) }}
         eslint:
+          - 8
           - 7
           - 6
           - 5
@@ -52,6 +53,15 @@ jobs:
             eslint: 4
           - node-version: 4
             eslint: 3
+        exclude:
+          - node-version: 15
+            eslint: 8
+          - node-version: 13
+            eslint: 8
+          - node-version: 11
+            eslint: 8
+          - node-version: 10
+            eslint: 8
 
     steps:
       - uses: actions/checkout@v2
@@ -67,6 +77,8 @@ jobs:
         if: ${{ !matrix.ajv && matrix.eslint == 4 }}
       - run: npm install --no-save "ajv@6"
         if: ${{ !matrix.ajv && matrix.eslint == 5 }}
+      - run: npm install --no-save @eslint/eslintrc@0
+        if: ${{ matrix.eslint != 8 }}
       - run: npm prune > /dev/null
       - run: npm ls > /dev/null
       - run: npm uninstall --no-save @eslint/eslintrc

package.json

@@ -31,7 +31,7 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "@eslint/eslintrc": "^0.1.3",
+    "@eslint/eslintrc": "^0.4.3 || ^1.0.2",
     "cliui": "^3.2.0",
     "eslint-rule-documentation": "^1.0.23",
     "glob": "^7.1.6",
@@ -50,8 +50,8 @@
     "codecov": "^2.3.1",
     "commitizen": "^2.10.1",
     "cz-conventional-changelog": "^2.1.0",
-    "eslint": "^3.12.0 || ^4 || ^5 || ^6 || ^7",
-    "eslint-plugin-json": "^2.1.2",
+    "eslint": "^3.12.0 || ^4 || ^5 || ^6 || ^7 || ^8",
+    "eslint-plugin-json": "^3.1.0",
     "ghooks": "^2.0.4",
     "in-publish": "^2.0.1",
     "mocha": "^3.5.3",
@@ -65,7 +65,7 @@
     "validate-commit-msg": "^2.14.0"
   },
   "peerDependencies": {
-    "eslint": "^3.12.0 || ^4 || ^5 || ^6 || ^7"
+    "eslint": "^3.12.0 || ^4 || ^5 || ^6 || ^7 || ^8"
   },
   "nyc": {
     "exclude": [

src/lib/rule-finder.js

@@ -1,6 +1,6 @@
 const path = require('path');
 
-const eslint = require('eslint');
+const { CLIEngine, ESLint, linter, Linter } = require('eslint');
 const glob = require('glob');
 const isAbsolute = require('path-is-absolute');
 const difference = require('./array-diff');
@@ -19,15 +19,29 @@ function _getConfigFile(specifiedFile) {
 }
 
 function _getConfigs(configFile, files) {
-  const cliEngine = new eslint.CLIEngine({
+  if (ESLint) { // ESLint 7+
+    const cliEngine = new ESLint({
+      // Ignore any config applicable depending on the location on the filesystem
+      useEslintrc: false,
+      // Point to the particular config
+      overrideConfigFile: configFile
+    });
+
+    return new Set(files
+      .map(filePath => cliEngine.isPathIgnored(filePath) ? false : cliEngine.calculateConfigForFile(filePath))
+      .filter(Boolean));
+  }
+
+  const cliEngine = new CLIEngine({
     // Ignore any config applicable depending on the location on the filesystem
     useEslintrc: false,
     // Point to the particular config
     configFile
   });
+
   return new Set(files
-                 .map(filePath => cliEngine.isPathIgnored(filePath) ? false : cliEngine.getConfigForFile(filePath))
-                 .filter(Boolean));
+    .map(filePath => cliEngine.isPathIgnored(filePath) ? false : cliEngine.getConfigForFile(filePath))
+    .filter(Boolean));
 }
 
 function _getConfig(configFile, files) {
@@ -67,7 +81,7 @@ function _getPluginRules(config) {
 }
 
 function _getCoreRules() {
-  return eslint.linter.getRules();
+  return (Linter ? new Linter() : linter).getRules();
 }
 
 function _filterRuleNames(ruleNames, rules, predicate) {

test/lib/rule-finder.js

@@ -4,22 +4,24 @@ const proxyquire = require('proxyquire');
 
 let ModuleResolver;
 try {
-  // eslint 7.12+
-  ModuleResolver = require('@eslint/eslintrc/lib/shared/relative-module-resolver');
+  // ESLint 7.12+
+  ModuleResolver = require('@eslint/eslintrc').Legacy.ModuleResolver;
 } catch (err) {
   if (err.code !== 'MODULE_NOT_FOUND') {
     throw err;
   }
+
   try {
-    // eslint v6 - v7.11: load the actual module
+    // ESLint v6 - v7.11: load the actual module
     ModuleResolver = require('eslint/lib/shared/relative-module-resolver');
   } catch (err) {
     if (err.code !== 'MODULE_NOT_FOUND') {
       throw err;
     }
-    // eslint < 6: ModuleResolver is `undefined`, which is okay. The proxyquire
+
+    // ESLint < 6: ModuleResolver is `undefined`, which is okay. The proxyquire
     // override for ../shared/relative-module-resolver won't be used because
-    // eslint < 6 does not have that module and so does not try to load it.
+    // ESLint < 6 does not have that module and so does not try to load it.
     ModuleResolver = undefined;
   }
 }
@@ -54,27 +56,41 @@ const moduleResolver = {
 
 const getRuleFinder = proxyquire('../../src/lib/rule-finder', {
   eslint: {
-    linter: {
+    linter: () => ({
+      getRules() {
+        return new Map()
+            .set('foo-rule', {})
+            .set('old-rule', {meta: {deprecated: true}})
+            .set('bar-rule', {})
+            .set('baz-rule', {});
+      }
+    }),
+    Linter: () => ({
       getRules() {
         return new Map()
           .set('foo-rule', {})
           .set('old-rule', {meta: {deprecated: true}})
           .set('bar-rule', {})
           .set('baz-rule', {});
       }
+    })
+  },
+  '@eslint/eslintrc': {
+    Legacy: {
+      ModuleResolver: moduleResolver,
     }
   },
   //
-  // This following module override is needed for eslint v6 and over. The module
-  // path that we pass here is literally the one used in eslint (specifically in
+  // This following module override is needed for ESLint v6 and over. The module
+  // path that we pass here is literally the one used in ESLint (specifically in
   // eslint/lib/cli-engine/config-array-factory.js)
   //
   // The stock `resolve` method attempts to resolve to a file path the module
   // name passed in `name` relative to the path in `relative`. We have to
-  // override that function, otherwise eslint fails to "load" our plugins.
+  // override that function, otherwise ESLint fails to "load" our plugins.
   //
-  '../shared/relative-module-resolver': moduleResolver, // in eslint < 7.12, from eslint/lib/cli-engine/config-array-factory.js
-  './shared/relative-module-resolver': moduleResolver, // in eslint 7.12+, from @eslint/eslintrc/lib/config-array-factory.js
+  '../shared/relative-module-resolver': moduleResolver, // in ESLint < 7.12, from eslint/lib/cli-engine/config-array-factory.js
+  './shared/relative-module-resolver': moduleResolver, // in ESLint 7.12+, from @eslint/eslintrc/lib/config-array-factory.js
   'eslint-plugin-plugin': {
     rules: {
       'foo-rule': {},
@@ -156,19 +172,34 @@ const dedupeModuleResolver = {
 };
 const getRuleFinderForDedupeTests = proxyquire('../../src/lib/rule-finder', {
   eslint: {
-    linter: {
+    linter: () => ({
+      getRules() {
+        return new Map()
+            .set('foo-rule', {})
+            .set('bar-rule', {})
+            .set('plugin/duplicate-foo-rule', {})
+            .set('plugin/duplicate-bar-rule', {});
+      }
+    }),
+    Linter: () => ({
       getRules() {
         return new Map()
           .set('foo-rule', {})
           .set('bar-rule', {})
           .set('plugin/duplicate-foo-rule', {})
           .set('plugin/duplicate-bar-rule', {});
       }
+    })
+  },
+
+  '@eslint/eslintrc': {
+    Legacy: {
+      ModuleResolver: dedupeModuleResolver,
     }
   },
   // See the long comment in `getRuleFinder` above to learn what the point of this override is.
-  '../shared/relative-module-resolver': dedupeModuleResolver, // in eslint < 7.12, from eslint/lib/cli-engine/config-array-factory.js
-  './shared/relative-module-resolver': dedupeModuleResolver, // in eslint 7.12+, from @eslint/eslintrc/lib/config-array-factory.js
+  '../shared/relative-module-resolver': dedupeModuleResolver, // in ESLint < 7.12, from eslint/lib/cli-engine/config-array-factory.js
+  './shared/relative-module-resolver': dedupeModuleResolver, // in ESLint 7.12+, from @eslint/eslintrc/lib/config-array-factory.js
   'eslint-plugin-plugin': {
     rules: {
       'duplicate-foo-rule': {},