Support ESLint 10

.github/workflows/main.yml

@@ -29,7 +29,7 @@ jobs:
       - uses: actions/setup-node@v4
         with:
           node-version: ${{ matrix.node-version }}
-      - run: npm install
+      - run: npm install --legacy-peer-deps
       - run: npx c8 ava
       - uses: codecov/codecov-action@v5
         with:
@@ -42,14 +42,14 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
-      - run: npm install
+      - run: npm install --legacy-peer-deps
       - run: npm run lint
   run-rules-on-codebase:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
-      - run: npm install
+      - run: npm install --legacy-peer-deps
       - run: npm run run-rules-on-codebase
   integration:
     name: Integration test (${{ matrix.group }})
@@ -72,5 +72,5 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
-      - run: npm install
+      - run: npm install --legacy-peer-deps
       - run: npm run integration -- --group ${{ matrix.group }}

.github/workflows/smoke-test.yml

@@ -11,7 +11,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
-      - run: npm install
+      - run: npm install --legacy-peer-deps
       - uses: AriPerkkio/eslint-remote-tester-run-action@v5
         with:
           issue-title: "Results of weekly scheduled smoke test"

.github/workflows/update-snapshots.yml

@@ -15,7 +15,7 @@ jobs:
         with:
           # Locked due to the difference of `zlib.gzipSync()` between Node.js versions
           node-version: 24
-      - run: npm install
+      - run: npm install --legacy-peer-deps
       - run: npm run lint
       - run: rm -rf test/snapshots
       # Force update snapshots, https://github.com/avajs/ava/discussions/2754

package.json

@@ -85,7 +85,7 @@
 		"ava": "^6.4.1",
 		"c8": "^10.1.3",
 		"enquirer": "^2.4.1",
-		"eslint": "^9.38.0",
+		"eslint": "^10.0.0-beta.0",
 		"eslint-ava-rule-tester": "^5.0.1",
 		"eslint-config-xo": "^0.49.0",
 		"eslint-doc-generator": "^2.3.0",
@@ -109,7 +109,7 @@
 		"yaml": "^2.8.1"
 	},
 	"peerDependencies": {
-		"eslint": ">=9.38.0"
+		"eslint": ">=9.38.0 || >=10.0.0-0"
 	},
 	"ava": {
 		"files": [

rules/custom-error-definition.js

@@ -1,4 +1,7 @@
-import {upperFirst} from './utils/index.js';
+import {
+	upperFirst,
+	getParenthesizedText,
+} from './utils/index.js';
 
 const MESSAGE_ID_INVALID_EXPORT = 'invalidExport';
 const messages = {
@@ -121,7 +124,12 @@ function * customErrorDefinition(context, node) {
 				if (superExpression.expression.arguments.length === 0) {
 					const rhs = expression.expression.right;
 					const [start] = sourceCode.getRange(superExpression);
-					yield fixer.insertTextAfterRange([start, start + 6], rhs.raw || rhs.name);
+					// This part crashes on ESLint 10, but it's still not correct.
+					// There can be spaces, comments after `super`
+					yield fixer.insertTextAfterRange(
+						[start, start + 6],
+						getParenthesizedText(rhs, context),
+					);
 				}
 
 				const start = messageExpressionIndex === 0

rules/prefer-string-slice.js

@@ -48,7 +48,7 @@ function * fixSubstrArguments({node, fixer, context, abort}) {
 		}
 
 		if (typeof getNumericValue(secondArgument) === 'number') {
-			yield replaceSecondArgument(Math.max(0, getNumericValue(secondArgument)));
+			yield replaceSecondArgument(String(Math.max(0, getNumericValue(secondArgument))));
 			return;
 		}
 
@@ -58,7 +58,7 @@ function * fixSubstrArguments({node, fixer, context, abort}) {
 	}
 
 	if (argumentNodes.every(node => isNumericLiteral(node))) {
-		yield replaceSecondArgument(firstArgument.value + secondArgument.value);
+		yield replaceSecondArgument(String(firstArgument.value + secondArgument.value));
 		return;
 	}
 
@@ -78,7 +78,7 @@ function * fixSubstringArguments({node, fixer, context, abort}) {
 		}
 
 		if (firstNumber !== undefined) {
-			yield replaceFirstArgument(Math.max(0, firstNumber));
+			yield replaceFirstArgument(String(Math.max(0, firstNumber)));
 			return;
 		}
 
@@ -99,18 +99,18 @@ function * fixSubstringArguments({node, fixer, context, abort}) {
 		}
 
 		if (argumentsValue[0] !== firstNumber) {
-			yield replaceFirstArgument(argumentsValue[0]);
+			yield replaceFirstArgument(String(argumentsValue[0]));
 		}
 
 		if (argumentsValue[1] !== secondNumber) {
-			yield replaceSecondArgument(argumentsValue[1]);
+			yield replaceSecondArgument(String(argumentsValue[1]));
 		}
 
 		return;
 	}
 
 	if (firstNumber === 0 || secondNumber === 0) {
-		yield replaceFirstArgument(0);
+		yield replaceFirstArgument('0');
 		yield replaceSecondArgument(`Math.max(0, ${firstNumber === 0 ? secondArgumentText : firstArgumentText})`);
 		return;
 	}

scripts/parsers.js

@@ -0,0 +1,97 @@
+/*
+Based on https://github.com/eslint/eslint/pull/20132
+Workaround for https://github.com/typescript-eslint/typescript-eslint/issues/11762
+*/
+
+import {Variable} from 'eslint-scope';
+import typescriptEslintParserOriginal from '@typescript-eslint/parser';
+import babelEslintParserOriginal from '@babel/eslint-parser';
+import vueEslintParserOriginal from 'vue-eslint-parser';
+
+function addGlobals(names) {
+	const globalScope = this.scopes[0];
+	for (const name of names) {
+		let variable = globalScope.set.get(name);
+
+		if (variable) {
+			continue;
+		}
+
+		variable = new Variable(name, globalScope);
+
+		globalScope.variables.push(variable);
+		globalScope.set.set(name, variable);
+	}
+
+	/*
+	 * "through" contains all references which definitions cannot be found.
+	 * Since we augment the global scope we need to update references
+	 * and remove the ones that were added.
+	 *
+	 * Also, typescript-eslint's scope manager doesn't resolve references
+	 * to global `var` and `function` variables, so we'll resolve _all_
+	 * references to variables that exist in the global scope.
+	 */
+	globalScope.through = globalScope.through.filter(reference => {
+		const {name} = reference.identifier;
+		const variable = globalScope.set.get(name);
+
+		if (variable) {
+			/*
+			 * Links the variable and the reference.
+			 * And this reference is removed from `Scope#through`.
+			 */
+			reference.resolved = variable;
+			variable.references.push(reference);
+
+			return false;
+		}
+
+		return true;
+	});
+
+	/*
+	 * "implicit" contains information about implicit global variables (those created
+	 * implicitly by assigning values to undeclared variables in non-strict code).
+	 * Since we augment the global scope, we need to remove the ones that were added.
+	 */
+	const {implicit} = globalScope;
+	implicit.variables = implicit.variables.filter(variable => {
+		const {name} = variable;
+		if (globalScope.set.has(name)) {
+			implicit.set.delete(name);
+			return false;
+		}
+
+		return true;
+	});
+
+	// Typescript-eslint's scope manager doesn't produce "implicit.left"
+}
+
+function fixParse(parse) {
+	return function parseForESLint(...arguments_) {
+		const result = parse(...arguments_);
+
+		if (result.scopeManager) {
+			result.scopeManager.addGlobals ??= addGlobals;
+		}
+
+		return result;
+	};
+}
+
+export const typescriptEslintParser = {
+	...typescriptEslintParserOriginal,
+	parseForESLint: fixParse(typescriptEslintParserOriginal.parseForESLint),
+};
+
+export const babelEslintParser = {
+	...babelEslintParserOriginal,
+	parseForESLint: fixParse(babelEslintParserOriginal.parseForESLint),
+};
+
+export const vueEslintParser = {
+	...vueEslintParserOriginal,
+	parseForESLint: fixParse(vueEslintParserOriginal.parseForESLint),
+};

test/custom-error-definition.js

@@ -457,6 +457,28 @@ const tests = {
 			`,
 			errors: [passMessageToSuperError],
 		},
+		{
+			code: outdent`
+				class FooError extends Error {
+					constructor() {
+						super();
+						this.message = foo.error;
+						this.name = 'FooError';
+					}
+				}
+			`,
+			output: outdent`
+				class FooError extends Error {
+					constructor() {
+						super(foo.error);
+						this.name = 'FooError';
+					}
+				}
+			`,
+			errors: [
+				passMessageToSuperError,
+			],
+		},
 	],
 };
 

test/expiring-todo-comments.js

@@ -55,7 +55,6 @@ test({
 		'// FIXME [2200-12-12] (lubien): Too long... Can you feel it?',
 		{
 			code: '// Expire Condition [2200-12-12]: new term name',
-			errors: [],
 			options: [{terms: ['Expire Condition']}],
 		},
 		'// Expire Condition [2000-01-01]: new term name',
@@ -80,19 +79,15 @@ test({
 		  */`,
 		{
 			code: '// TODO',
-			errors: [],
 		},
 		{
 			code: '// TODO [invalid]',
-			errors: [],
 		},
 		{
 			code: '// TODO [] might have [some] that [try [to trick] me]',
-			errors: [],
 		},
 		{
 			code: '// TODO [but [it will]] [fallback] [[[ to the default ]]] rule [[',
-			errors: [],
 		},
 		{
 			code: '// TODO ISSUE-123 fix later',

test/integration/projects.js

@@ -38,7 +38,13 @@ export default [
 				'test-tap/fixture/report/edgecases/ast-syntax-error.cjs',
 			],
 		},
-		'https://github.com/chalk/chalk',
+		{
+			repository: 'https://github.com/chalk/chalk',
+			ignore: [
+				// Uses `/* eslint-env */`
+				'source/vendor/supports-color/browser.js',
+			],
+		},
 		'https://github.com/chalk/wrap-ansi',
 		'https://github.com/sindresorhus/np',
 		'https://github.com/sindresorhus/ora',
@@ -113,7 +119,15 @@ export default [
 				'importAssertions',
 			],
 		},
-		'https://github.com/ReactTraining/react-router',
+		{
+			repository: 'https://github.com/ReactTraining/react-router',
+			ignore: [
+				// Uses `/* eslint-env */`
+				'packages/react-router/lib/dom/node-main.js',
+				'packages/react-router/node-main-dom-export.js',
+				'packages/react-router/node-main.js',
+			],
+		},
 		// #902
 		{
 			repository: 'https://github.com/reakit/reakit',
@@ -146,6 +160,13 @@ export default [
 		{
 			repository: 'https://github.com/TheThingsNetwork/lorawan-stack',
 			babelPlugins: ['decorators'],
+			ignore: [
+				// Uses `/* eslint-env */`
+				'config/storybook/webpack.config.js',
+				'config/webpack.config.babel.js',
+				'config/webpack.dll.babel.js',
+				'pkg/webui/lib/get-by-path_test.js',
+			],
 		},
 		'https://github.com/zloirock/core-js',
 		{
@@ -184,6 +205,10 @@ export default [
 			'test/**',
 			'**/tests/**',
 			'**/compiled/**',
+
+			// Uses `/* eslint-env */`
+			'packages/next/src/server/lib/router-utils/decode-path-params.test.ts',
+			'packages/next/src/server/node-polyfill-crypto.test.ts',
 		],
 	},
 	// #903
@@ -204,6 +229,10 @@ export default [
 
 			// Global return
 			'scripts/cypress.js',
+
+			// Uses `/* eslint-env */`
+			'packages/charts/chart-web-components/scripts/e2e.js',
+			'packages/web-components/scripts/e2e.js',
 		],
 	},
 	{
@@ -236,6 +265,8 @@ export default [
 			'src/vs/platform/files/test/node/fixtures/**',
 			'src/vs/workbench/services/search/test/node/fixtures/examples/**',
 			'extensions/vscode-colorize-perf-tests/test/**',
+			// Uses `/* eslint-env */`
+			'test/unit/electron/renderer.js',
 		],
 	},
 ].flatMap((projectOrProjects, index) =>