CI: use the Joomla matrix of the plugin repository

.github/workflows/ci.yml

@@ -54,32 +54,18 @@ jobs:
       - name: Check PHP syntax
         run: find . -name '*.php' -not -path './.git/*' -print0 | xargs -0 -n1 php -l
 
-  integration:
-    name: Joomla ${{ matrix.joomla }}, ${{ matrix.db }}, PHP ${{ matrix.php }}
+  # The Joomla!/PHP/database combinations are those of the plugin repository
+  # (tests/ci/matrix.json there), so that both repositories test the same
+  # combinations and the matrix is raised in one place only. The plugin branch
+  # is chosen here, once, so that the matrix and the code tested come from the
+  # same checkout.
+  matrix:
+    name: Test matrix
     runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - { joomla: 5.4.8, php: '8.2', db: 'mysql:8.0' }
-          - { joomla: 5.4.8, php: '8.2', db: 'postgres:12' }
-          - { joomla: 6.1.3, php: '8.4', db: 'mariadb:11.4' }
-          - { joomla: 6.1.3, php: '8.4', db: 'postgres:17' }
-    env:
-      JOOMLA_VERSION: ${{ matrix.joomla }}
-      DB_HOST: 127.0.0.1
-      DB_NAME: joomla
-      DB_PASS: bfstop-test
+    outputs:
+      matrix: ${{ steps.read.outputs.matrix }}
+      plugin-ref: ${{ steps.plugin.outputs.ref }}
     steps:
-      - name: Set paths
-        run: |
-          {
-            echo "JOOMLA_ROOT=$RUNNER_TEMP/joomla"
-            echo "COM_BFSTOP_ROOT=$GITHUB_WORKSPACE"
-            echo "PLUGIN_ROOT=$RUNNER_TEMP/bfstop"
-          } >> "$GITHUB_ENV"
-      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
-
       # use the plugin's branch of the same name if there is one and it
       # has commits main hasn't (for changes spanning both), else main: a
       # branch which was merged and not deleted is a stale copy of an old main
@@ -104,6 +90,36 @@ jobs:
         with:
           repository: codeling/bfstop
           ref: ${{ steps.plugin.outputs.ref }}
+          sparse-checkout: tests/ci
+      - id: read
+        run: |
+          echo "matrix=$(jq -c '{include: .include}' tests/ci/matrix.json)" >> "$GITHUB_OUTPUT"
+
+  integration:
+    name: Joomla ${{ matrix.joomla }}, ${{ matrix.db }}, PHP ${{ matrix.php }}
+    needs: matrix
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix: ${{ fromJson(needs.matrix.outputs.matrix) }}
+    env:
+      JOOMLA_VERSION: ${{ matrix.joomla }}
+      DB_HOST: 127.0.0.1
+      DB_NAME: joomla
+      DB_PASS: bfstop-test
+    steps:
+      - name: Set paths
+        run: |
+          {
+            echo "JOOMLA_ROOT=$RUNNER_TEMP/joomla"
+            echo "COM_BFSTOP_ROOT=$GITHUB_WORKSPACE"
+            echo "PLUGIN_ROOT=$RUNNER_TEMP/bfstop"
+          } >> "$GITHUB_ENV"
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          repository: codeling/bfstop
+          ref: ${{ needs.matrix.outputs.plugin-ref }}
           path: bfstop
       - name: Move bfstop checkout out of the component's
         run: mv bfstop "$PLUGIN_ROOT"