php-fpm: correct job order & matrix empty output

.github/workflows/php-fpm.yml

@@ -22,12 +22,11 @@ on:
 
 jobs:
   build:
+    needs: lanes
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
-      matrix:
-        # This matrix will be dynamically populated by the 'lanes' job
-        lane: []
+      matrix: ${{ fromJson(needs.lanes.outputs.matrix) }}
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
@@ -125,6 +124,9 @@ jobs:
           else
             # Determine changed lanes from php-fpm directory
             changed_lanes=$(echo "${{ steps.changed-files.outputs.all_changed_files }}" | tr ' ' '\n' | grep '^php-fpm/' | cut -d'/' -f2 | sort -u | jq -R . | jq -s .)
+            if [[ -z "$changed_lanes" ]]; then
+              changed_lanes="[]"
+            fi
             matrix="{\"lane\":$changed_lanes}"
           fi