Only provide test_images_report if folder isn't empty

Author: puehringer

.github/workflows/build-docker-artifacts.yml

@@ -296,7 +296,7 @@ jobs:
           vuln-type: "os,library"
           severity: ${{ steps.set_severity.outputs.severity }}
           # The cache update takes quite long, so let's try to disable it for now: https://github.com/aquasecurity/trivy-action#cache
-          cache: 'false'
+          cache: "false"
         continue-on-error: false
 
       - name: Push image
@@ -353,15 +353,17 @@ jobs:
               export "IMAGE_${name_upper}=${image_ref}"
             done;
 
-            # Create report folder to avoid any downstream Docker volume issues
-            # TODO: For some reason this doesn't work yet, i.e. if a docker-compose script mounts a volume here, nothing shows up...
+            # Create a directory to store the report results
             mkdir -p "$test_images_report"
-            chmod 777 "$test_images_report"
-            echo "test_images_report=${test_images_report}" >> "$GITHUB_OUTPUT"
 
             echo "Run $test_images_hook"
             chmod +x "$test_images_hook"
             bash "$test_images_hook"
+
+            # If the report folder is not empty, we store it as output
+            if [[ -n "$(ls -A "$test_images_report")" ]]; then
+              echo "test_images_report=${test_images_report}" >> "$GITHUB_OUTPUT"
+            fi
           else
             echo "No $test_images_hook found, skipping tests."
           fi