Chore: add test for eslint v9 (#694)

Author: ota-meshi

.github/workflows/NodeCI.yml

@@ -12,8 +12,6 @@ jobs:
         steps:
             - uses: actions/checkout@v4
             - uses: actions/setup-node@v4
-              with:
-                  node-version: 18
             - name: Install Packages
               run: npm ci
             - name: Build
@@ -24,15 +22,21 @@ jobs:
         runs-on: ubuntu-latest
         strategy:
             matrix:
-                node-version: [18.x, 20.x]
+                node: [18.x, 20.x]
+                eslint: [8, ^9.0.0-0]
         steps:
             - uses: actions/checkout@v4
-            - name: Use Node.js ${{ matrix.node-version }}
+            - name: Use Node.js ${{ matrix.node }}
               uses: actions/setup-node@v4
               with:
-                  node-version: ${{ matrix.node-version }}
+                  node-version: ${{ matrix.node }}
+            - name: Install ESLint ${{ matrix.eslint }}
+              # We use --legacy-peer-deps because we get a lot of dependency warnings when installing eslint v9-alpha.
+              run: npm i -D eslint@${{ matrix.eslint }} --legacy-peer-deps
             - name: Install Packages
-              run: npm ci
+              # run: npm ci
+              # We use `npm i` because there is an error regarding dependencies when installing eslint v9-alpha.
+              run: npm i -f
             - name: Test
               run: npm test
     test-and-coverage:
@@ -45,16 +49,14 @@ jobs:
             - name: Test
               run: npm run test:nyc
             - name: Coveralls GitHub Action
-              uses: coverallsapp/github-action@3dfc5567390f6fa9267c0ee9c251e4c8c3f18949 # v2.2.3
+              uses: coverallsapp/github-action@v2
               with:
                   github-token: ${{ secrets.GITHUB_TOKEN }}
     update:
         runs-on: ubuntu-latest
         steps:
             - uses: actions/checkout@v4
             - uses: actions/setup-node@v4
-              with:
-                  node-version: 18
             - name: Install Packages
               run: npm ci
             - name: Build

package-lock.json

@@ -79,7 +79,7 @@
         "eslint-config-prettier": "^9.0.0",
         "eslint-doc-generator": "^1.4.1",
         "eslint-plugin-eslint-comments": "^3.2.0",
-        "eslint-plugin-eslint-plugin": "^5.0.0",
+        "eslint-plugin-eslint-plugin": "^5.2.1",
         "eslint-plugin-json-schema-validator": "^4.6.1",
         "eslint-plugin-jsonc": "^2.0.0",
         "eslint-plugin-n": "^16.0.0",
@@ -95,6 +95,7 @@
         "nyc": "^15.1.0",
         "pako": "^2.1.0",
         "prettier": "~3.2.0",
+        "semver": "^7.5.4",
         "stylelint": "^16.0.0",
         "stylelint-config-standard-vue": "^1.0.0",
         "ts-node": "^10.2.1",

package.json

@@ -2,6 +2,7 @@ import path from "path"
 import assert from "assert"
 import { ESLint } from "eslint"
 import * as plugin from "../../lib/index"
+import semver from "semver"
 
 // -----------------------------------------------------------------------------
 // Tests
@@ -10,6 +11,10 @@ import * as plugin from "../../lib/index"
 const TEST_CWD = path.join(__dirname, "../fixtures/integrations/eslint-plugin")
 
 describe("Integration with eslint-plugin-regexp", () => {
+    if (semver.gte(ESLint.version, "9.0.0-0")) {
+        // TODO: We don't support flat-config yet so we can't test it.
+        return
+    }
     it("should lint without errors", async () => {
         let results: ESLint.LintResult[]
         if (ESLint) {

tests/lib/eslint-plugin.ts

@@ -0,0 +1,12 @@
+import { RuleTester as OriginalRuleTester } from "eslint"
+
+export const RuleTester = getUnsupportedFlatRuleTester() || OriginalRuleTester
+
+function getUnsupportedFlatRuleTester() {
+    try {
+        // eslint-disable-next-line @typescript-eslint/no-require-imports, @typescript-eslint/no-var-requires -- for test
+        return require("eslint/use-at-your-own-risk").FlatRuleTester
+    } catch {
+        return null
+    }
+}

tests/lib/rule-tester.ts

@@ -60,17 +60,23 @@ describe("Don't crash even if with unknown flag.", () => {
     }
 
     const pluginRules = Object.fromEntries(
-        Object.values(rules).map((rule) => [rule.meta.docs.ruleId, rule]),
+        Object.values(rules).map((rule) => [rule.meta.docs.ruleName, rule]),
     )
 
     for (const rule of Object.values(rules)) {
         const ruleId = rule.meta.docs.ruleId
 
         it(ruleId, () => {
-            const linter = new Linter()
+            const linter = new Linter({ configType: "flat" })
             const config: Linter.Config = {
-                parser: "@typescript-eslint/parser",
-                parserOptions: {
+                plugins: {
+                    // @ts-expect-error -- ignore type error for eslint v9
+                    regexp: {
+                        rules: { ...pluginRules, test: TEST_RULE },
+                    },
+                },
+                languageOptions: {
+                    parser,
                     ecmaVersion: 2020,
                 },
                 rules: {
@@ -81,11 +87,7 @@ describe("Don't crash even if with unknown flag.", () => {
                         : {}),
                 },
             }
-            // @ts-expect-error -- ignore
-            linter.defineParser("@typescript-eslint/parser", parser)
-            linter.defineRules(pluginRules)
 
-            linter.defineRule("regexp/test", TEST_RULE)
             const resultVue = linter.verifyAndFix(code, config, "test.js")
 
             assert.deepStrictEqual(

tests/lib/rules-with-unknown-flag.ts

@@ -1,8 +1,8 @@
-import { RuleTester } from "eslint"
+import { RuleTester } from "../rule-tester"
 import rule from "../../../lib/rules/confusing-quantifier"
 
 const tester = new RuleTester({
-    parserOptions: {
+    languageOptions: {
         ecmaVersion: "latest",
         sourceType: "module",
     },

tests/lib/rules/confusing-quantifier.ts

@@ -1,8 +1,8 @@
-import { RuleTester } from "eslint"
+import { RuleTester } from "../rule-tester"
 import rule from "../../../lib/rules/control-character-escape"
 
 const tester = new RuleTester({
-    parserOptions: {
+    languageOptions: {
         ecmaVersion: "latest",
         sourceType: "module",
     },

tests/lib/rules/control-character-escape.ts

@@ -1,8 +1,8 @@
-import { RuleTester } from "eslint"
+import { RuleTester } from "../rule-tester"
 import rule from "../../../lib/rules/grapheme-string-literal"
 
 const tester = new RuleTester({
-    parserOptions: {
+    languageOptions: {
         ecmaVersion: "latest",
         sourceType: "module",
     },

tests/lib/rules/grapheme-string-literal.ts

@@ -1,8 +1,8 @@
-import { RuleTester } from "eslint"
+import { RuleTester } from "../rule-tester"
 import rule from "../../../lib/rules/hexadecimal-escape"
 
 const tester = new RuleTester({
-    parserOptions: {
+    languageOptions: {
         ecmaVersion: "latest",
         sourceType: "module",
     },