GLSP-1634: Update to eslint 9.x (#1638)

-Update eslint, config and transitive dependencies for 9.x
Part of #1634

Also:
- Minor fix in check:headers script and update of root scripts

Author: tortmayr

.eslintignore

@@ -4,3 +4,9 @@ lib
 dist
 tsconfig.tsbuildinfo
 eslint.xml
+
+# Agent specific files
+.claude/plans
+.claude/settings.local.json
+CLAUDE.local.md
+.reviews

.eslintrc.js

@@ -14,4 +14,8 @@ package-lock.json
 yarn.lock
 
 # Logs
-*.log
+*.log
+
+# Claude Code
+.claude/
+.reviews/

.gitignore

@@ -0,0 +1,51 @@
+# Repository Guidelines
+
+## Project Structure & Module Organization
+
+This repository is a Yarn workspaces monorepo for shared GLSP development tooling.
+
+-   `dev-packages/*`: publishable workspace packages (`cli`, `config`, `config-test`, `eslint-config`, `mocha-config`, `nyc-config`, `prettier-config`, `ts-config`, `dev`).
+-   `dev-packages/cli/src`: TypeScript sources for the `glsp` CLI (`commands/` and `util/`).
+-   `.github/workflows`: CI, release, and publishing workflows.
+-   `docker/` and `releng/`: container and release-engineering assets.
+-   Root configs: `eslint.config.mjs`, `tsconfig*.json`, `.prettierrc`, `lerna.json`.
+
+## Build, Test, and Development Commands
+
+Use Node `>=20` and Yarn classic (`>=1.7.0 <2`).
+
+-   `yarn install`: install dependencies and build via `prepare`.
+-   `yarn build`: run `lerna run build` across workspaces.
+-   `yarn watch`: watch CLI bundle changes.
+-   `yarn lint` / `yarn lint:fix`: run ESLint (or auto-fix).
+-   `yarn format` / `yarn format:check`: apply/check Prettier formatting.
+-   `yarn check:headers`: verify copyright headers against git history.
+-   `yarn check:pr`: CI-style local gate (`install`, lint, format check, headers).
+
+## Coding Style & Naming Conventions
+
+-   Language: TypeScript for source code.
+-   Formatting: Prettier (`.prettierrc`) with 4-space indentation, single quotes, no trailing commas, LF line endings.
+-   JSON/YAML formatting uses 2-space indentation.
+-   Linting: ESLint flat config (`eslint.config.mjs`) with GLSP shared rules.
+-   Naming: keep command implementations in `dev-packages/cli/src/commands/*.ts`; shared helpers in `dev-packages/cli/src/util/*.ts`.
+
+## Testing Guidelines
+
+There is currently no root `test` script in this repository. Validate contributions with:
+
+-   `yarn build`
+-   `yarn lint`
+-   `yarn format:check`
+-   `yarn check:headers`
+
+For new testable packages, use GLSP shared test config (`@eclipse-glsp/config-test`) and Mocha/nyc conventions (`*.spec.ts`, coverage via `test:coverage`).
+
+## Commit & Pull Request Guidelines
+
+-   Open an issue in `https://github.com/eclipse-glsp/glsp` before coding.
+-   Branch naming: `issues/<issue_number>` (example: `issues/123`).
+-   Commit messages: imperative subject; issue references are expected (examples in history include `GLSP-1594: ... (#1596)`).
+-   Include closing reference with absolute URL, e.g. `closes https://github.com/eclipse-glsp/glsp/issues/241`.
+-   PRs should include scope, linked issue, and pass CI; ensure `yarn.lock` has no unintended diff.
+-   Ensure Eclipse Contributor Agreement (ECA) requirements are satisfied.

.prettierignore

@@ -0,0 +1 @@
+@AGENTS.md

AGENTS.md

@@ -116,7 +116,7 @@ All changes on the master branch are deployed automatically to the corresponding
 
 ### Client packages
 
-We recommend node in version 18 or higher:
+We recommend node in version 20 or higher:
 
 ```bash
 curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.3/install.sh | bash
@@ -137,7 +137,7 @@ npm install -g lerna
 
 ### Server/Ide packages
 
-You'll need Java 17 and maven.
+You'll need Java 21 and maven.
 
 ## Building
 

CLAUDE.md

@@ -1,5 +1,5 @@
 /********************************************************************************
- * Copyright (c) 2022-2025 EclipseSource and others.
+ * Copyright (c) 2022-2026 EclipseSource and others.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
@@ -13,7 +13,6 @@
  *
  * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
  ********************************************************************************/
-/* eslint-disable max-len */
 import { Option } from 'commander';
 import * as fs from 'fs';
 import { glob } from 'glob';
@@ -44,6 +43,7 @@ export interface HeaderCheckOptions {
     json: boolean;
     excludeDefaults: boolean;
     autoFix: boolean;
+    commit: boolean;
 }
 
 const checkTypes = ['full', 'changes', 'lastCommit'] as const;
@@ -79,7 +79,8 @@ export const CheckHeaderCommand = baseCommand() //
         'Disables the default excludes patterns. Only explicitly passed exclude patterns (-e, --exclude) are considered'
     )
     .option('-j, --json', 'Also persist validation results as json file', false)
-    .option('-a, --autoFix', 'Auto apply & commit fixes without prompting the user', false)
+    .option('-a, --autoFix', 'Auto apply fixes without prompting the user', false)
+    .option('--commit', 'When used with --autoFix, also create a git commit for the fixed files', false)
     .action(checkHeaders);
 
 export function checkHeaders(rootDir: string, options: HeaderCheckOptions): void {
@@ -263,7 +264,7 @@ function fixViolations(rootDir: string, violations: DateValidationResult[], opti
         replaceInFile(violation.file, RegExp('Copyright \\([cC]\\) ' + currentRange), `Copyright (c) ${fixedRange}`);
     });
     LOGGER.newLine();
-    if (options.autoFix || readline.keyInYN('Do you want to create a commit for the fixed files?')) {
+    if (options.commit && (options.autoFix || readline.keyInYN('Do you want to create a commit for the fixed files?'))) {
         LOGGER.newLine();
         const files = violations.map(violation => violation.file).join(' ');
         exec(`git add ${files}`);

README.md

@@ -1,5 +1,5 @@
 /********************************************************************************
- * Copyright (c) 2025 EclipseSource and others.
+ * Copyright (c) 2025-2026 EclipseSource and others.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
@@ -14,8 +14,8 @@
  * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
  ********************************************************************************/
 
-import path from 'path';
-import semver from 'semver';
+import * as path from 'path';
+import * as semver from 'semver';
 import { LOGGER, PackageHelper, configureExec, configureLogger, exec, getRemoteUrl, readFile, readPackage } from '../../util';
 
 export type GLSPRepo = (typeof GLSPRepo.choices)[number];