Relax ESLint peerDependency constraint to allow v9 (#16414)

.github/workflows/ci.yml

@@ -530,6 +530,31 @@ jobs:
       - name: Run babel/eslint tests
         run: node ./node_modules/.bin/jest eslint
 
+  eslint8-test:
+    name: Test @babel/eslint-* with ESLint 8.0.0
+    needs: build
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      - name: Use Node.js latest
+        uses: actions/setup-node@v4
+        with:
+          node-version: latest
+          check-latest: true
+          cache: "yarn"
+      - name: Install
+        run: yarn install
+      - uses: actions/download-artifact@v3
+        with:
+          name: babel-artifact
+      - name: Extract artifacts
+        run: tar -xf babel-artifact.tar; rm babel-artifact.tar
+      - name: Downgrade ESLint to 8.0.0
+        run: yarn up eslint@8.0.0
+      - name: Run babel/eslint tests
+        run: node ./node_modules/.bin/jest eslint
+
   test262-prepare:
     name: test262 - Prepare for running in parallel
     runs-on: ubuntu-latest

eslint/babel-eslint-parser/package.json

@@ -28,7 +28,7 @@
   },
   "peerDependencies": {
     "@babel/core": "^7.11.0",
-    "eslint": "^7.5.0 || ^8.0.0"
+    "eslint": "^7.5.0 || ^8.0.0 || ^9.0.0"
   },
   "dependencies": {
     "@nicolo-ribaudo/eslint-scope-5-internals": "condition:BABEL_8_BREAKING ? : 5.1.1-v1",
@@ -42,7 +42,7 @@
     "@types/estree": "^1.0.5",
     "@typescript-eslint/scope-manager": "^6.19.0",
     "dedent": "^0.7.0",
-    "eslint": "^8.22.0"
+    "eslint": "^9.0.0"
   },
   "conditions": {
     "BABEL_8_BREAKING": [
@@ -52,7 +52,7 @@
         },
         "peerDependencies": {
           "@babel/core": ">=7.11.0",
-          "eslint": "^8.9.0"
+          "eslint": "^8.9.0 || ^9.0.0"
         }
       },
       {}

eslint/babel-eslint-plugin/package.json

@@ -34,14 +34,14 @@
   "homepage": "https://babel.dev/",
   "peerDependencies": {
     "@babel/eslint-parser": "^7.11.0",
-    "eslint": "^7.5.0 || ^8.0.0"
+    "eslint": "^7.5.0 || ^8.0.0 || ^9.0.0"
   },
   "dependencies": {
     "eslint-rule-composer": "^0.3.0"
   },
   "devDependencies": {
     "clone-deep": "^4.0.1",
-    "eslint": "^8.22.0"
+    "eslint": "^9.0.0"
   },
   "conditions": {
     "BABEL_8_BREAKING": [
@@ -51,7 +51,7 @@
         },
         "peerDependencies": {
           "@babel/eslint-parser": "^7.11.0",
-          "eslint": "^8.9.0"
+          "eslint": "^8.9.0 || ^9.0.0"
         }
       },
       {}

eslint/babel-eslint-plugin/src/rules/new-cap.cjs

@@ -1,7 +1,12 @@
 const ruleComposer = require("eslint-rule-composer");
 const eslint = require("eslint");
+const eslintVersion = eslint.ESLint.version;
 
-const rule = new eslint.Linter().getRules().get("new-cap");
+const rule = (
+  parseInt(eslintVersion, 10) >= 9
+    ? require("eslint/use-at-your-own-risk").builtinRules
+    : new eslint.Linter().getRules()
+).get("new-cap");
 
 /**
  * Returns whether a node is under a decorator or not.

eslint/babel-eslint-plugin/src/rules/no-invalid-this.cjs

@@ -2,7 +2,11 @@ const ruleComposer = require("eslint-rule-composer");
 const eslint = require("eslint");
 const eslintVersion = eslint.ESLint.version;
 
-const noInvalidThisRule = new eslint.Linter().getRules().get("no-invalid-this");
+const noInvalidThisRule = (
+  parseInt(eslintVersion, 10) >= 9
+    ? require("eslint/use-at-your-own-risk").builtinRules
+    : new eslint.Linter().getRules()
+).get("no-invalid-this");
 
 if (parseInt(eslintVersion, 10) >= 8) {
   // ESLint 8 supports class properties / private methods natively

eslint/babel-eslint-plugin/src/rules/no-undef.cjs

@@ -1,7 +1,12 @@
 const ruleComposer = require("eslint-rule-composer");
 const eslint = require("eslint");
+const eslintVersion = eslint.ESLint.version;
 
-const rule = new eslint.Linter().getRules().get("no-undef");
+const rule = (
+  parseInt(eslintVersion, 10) >= 9
+    ? require("eslint/use-at-your-own-risk").builtinRules
+    : new eslint.Linter().getRules()
+).get("no-undef");
 
 /**
  * Returns whether a node is under a decorator or not.

eslint/babel-eslint-plugin/src/rules/no-unused-expressions.cjs

@@ -1,7 +1,12 @@
 const ruleComposer = require("eslint-rule-composer");
 const eslint = require("eslint");
+const eslintVersion = eslint.ESLint.version;
 
-const rule = new eslint.Linter().getRules().get("no-unused-expressions");
+const rule = (
+  parseInt(eslintVersion, 10) >= 9
+    ? require("eslint/use-at-your-own-risk").builtinRules
+    : new eslint.Linter().getRules()
+).get("no-unused-expressions");
 
 /**
  * @param {ASTNode} node - any node

eslint/babel-eslint-plugin/src/rules/object-curly-spacing.cjs

@@ -1,7 +1,12 @@
 const ruleComposer = require("eslint-rule-composer");
 const eslint = require("eslint");
+const eslintVersion = eslint.ESLint.version;
 
-const rule = new eslint.Linter().getRules().get("object-curly-spacing");
+const rule = (
+  parseInt(eslintVersion, 10) >= 9
+    ? require("eslint/use-at-your-own-risk").builtinRules
+    : new eslint.Linter().getRules()
+).get("object-curly-spacing");
 
 module.exports = ruleComposer.filterReports(rule, problem => {
   const node = problem.node;

eslint/babel-eslint-plugin/src/rules/semi.cjs

@@ -4,7 +4,11 @@ const eslintVersion = eslint.ESLint.version;
 
 const OPT_OUT_PATTERN = /^[-[(/+`]/; // One of [(/+-`
 
-const rule = new eslint.Linter().getRules().get("semi");
+const rule = (
+  parseInt(eslintVersion, 10) >= 9
+    ? require("eslint/use-at-your-own-risk").builtinRules
+    : new eslint.Linter().getRules()
+).get("semi");
 
 function isSemicolon(token) {
   return token.type === "Punctuator" && token.value === ";";

jest.config.js

@@ -65,6 +65,9 @@ module.exports = {
     ...(process.version === "v20.6.0"
       ? ["/babel-preset-env/test/regressions.js"]
       : []),
+    ...(!semver.satisfies(nodeVersion, "^18.18.0 || >=20.0")
+      ? ["<rootDir>/eslint/"]
+      : []),
   ],
   testEnvironment: "node",
   transformIgnorePatterns: [