Add pre-commit config and GitHub action to enforce its checks

Author: steve-s

.github/workflows/ci.yml

@@ -31,9 +31,36 @@ jobs:
         run: echo "maven_bundle_url=$(./scripts/maven-bundle-url.sh | tail -n 1)" >> $GITHUB_OUTPUT
         shell: bash
 
+  pre_commit:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Setup Java 21
+        id: java21
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 21
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+
+      - name: Install pre-commit
+        run: python -m pip install --upgrade pip pre-commit
+        shell: bash
+
+      - name: run pre-commit
+        run: pre-commit run --all-files
+        shell: bash
+
   build:
     runs-on: ${{ matrix.os }}
-    needs: maven_bundle_url
+    # pre_commit not needed, but is in 'needs' to avoid wasting CI cycles in case it doesn't pass
+    needs: [maven_bundle_url, pre_commit]
     strategy:
       matrix:
         os: [ubuntu-latest, windows-latest, macos-latest]
@@ -207,4 +234,4 @@ jobs:
 
       - name: Run Maven tests
         run: mvn --batch-mode -s settings.xml -Dgradle.java.home=$GRADLE_JAVA_HOME ${{ matrix.maven_args }}
-        shell: bash
+        shell: bash

.pre-commit-config.yaml

@@ -0,0 +1,22 @@
+repos:
+-   repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v5.0.0
+    hooks:
+    -   id: trailing-whitespace
+    -   id: end-of-file-fixer
+    -   id: check-yaml
+    -   id: check-added-large-files
+    -   id: check-xml
+    -   id: check-executables-have-shebangs
+    -   id: check-shebang-scripts-are-executable
+    -   id: check-symlinks
+    -   id: mixed-line-ending
+        args: ['--fix=no']
+-   repo: local
+    hooks:
+    -   id: maven-validate-spotless
+        name: Maven validate & spotless:apply
+        entry: ./mvnw
+        args: ['validate', 'spotless:apply']
+        language: system
+        pass_filenames: false