ci: test each MPS version separately to conserve disk space

Author: sergej-koscejev

.github/workflows/build.yml

@@ -5,21 +5,45 @@ name: Java CI with Gradle
 
 on:
   push:
-    branches: [ "main" ]
+    branches: main
   pull_request:
-    branches: [ "main" ]
 
 jobs:
-  build:
+  assemble:
     runs-on: ubuntu-latest
+    outputs:
+      mps_versions: ${{ steps.mps_versions.outputs.mps_versions }}
     steps:
       - uses: actions/checkout@v4
       - name: Set up JDK
         uses: actions/setup-java@v4
         with:
           distribution: 'temurin'
           java-version: '21'
-      - name: Setup Gradle
+      - name: Set up Gradle
         uses: gradle/actions/setup-gradle@v4
-      - name: Build with Gradle
-        run: ./gradlew build
+      - name: Assemble
+        run: ./gradlew assemble
+      - name: Output MPS versions
+        id: mps_versions
+        run: |
+          mps_versions=$(jq <gradle.properties --compact-output --raw-input 'select(startswith("supportedMpsVersions=")) | split("=") | .[1] | split(",")')
+          echo "mps_versions=$mps_versions" >> "$GITHUB_OUTPUT"
+
+  test:
+    needs: assemble
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        mps_version: ${{ fromJSON(needs.assemble.outputs.mps_versions) }}
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up JDK
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: '21'
+      - name: Set up Gradle
+        uses: gradle/actions/setup-gradle@v4
+      - name: Test
+        run: ./gradlew testMps${{ matrix.mps_version }}

gradle.properties

@@ -4,4 +4,5 @@ version.backend=1.24.3
 version.project-loader=5.0.0
 
 # A comma-separated list of MPS releases or prereleases to test against.
+# Also used in .github/build.yml to test each version in parallel
 supportedMpsVersions=2023.2.2,2024.1.2,2025.1.1,253.28294.219