fix: add fallback for empty image_tag in deployment

- Add validation and fallback logic for IMAGE_TAG
- If build job output is empty, generate tag from commit SHA
- Use 'latest' tag as last resort fallback
- Add debug output to show what tag is being used
- Fixes 'invalid reference format' error when IMAGE_TAG is empty

.gitea/workflows/production-deploy.yml

@@ -644,15 +644,47 @@ jobs:
           DEPLOYMENT_HOST="${{ env.DEPLOYMENT_HOST }}"
           REGISTRY="${{ env.REGISTRY }}"
           IMAGE_NAME="${{ env.IMAGE_NAME }}"
+          
+          # Get image tag from build job output with fallback
           IMAGE_TAG="${{ needs.build.outputs.image_tag }}"
+          
+          # Debug: Show what we got from the build job
+          echo "🔍 Debug: Build job output image_tag: '${IMAGE_TAG}'"
+          
+          # If IMAGE_TAG is empty or invalid, use fallback
+          if [ -z "$IMAGE_TAG" ] || [ "$IMAGE_TAG" = "..." ] || [ "$IMAGE_TAG" = "null" ]; then
+            echo "⚠️  Image tag from build job is empty or invalid, trying fallback..."
+            COMMIT_SHA="${{ github.sha }}"
+            if [ -z "$COMMIT_SHA" ]; then
+              # Try to get from git repo if checked out
+              COMMIT_SHA=$(cd /workspace/repo && git rev-parse HEAD 2>/dev/null || echo "")
+            fi
+            if [ -z "$COMMIT_SHA" ]; then
+              # Last resort: use latest tag (always exists after build)
+              echo "   Using 'latest' tag as fallback"
+              IMAGE_TAG="latest"
+            else
+              SHORT_SHA=$(echo "$COMMIT_SHA" | cut -c1-7)
+              IMAGE_TAG="git-${SHORT_SHA}"
+              echo "   Generated tag from commit SHA: ${IMAGE_TAG}"
+            fi
+          fi
+          
           FULL_IMAGE="${REGISTRY}/${IMAGE_NAME}:${IMAGE_TAG}"
           STACK_PATH="~/deployment/stacks/application"
           
           echo "🚀 Starting deployment..."
           echo "   Image: ${FULL_IMAGE}"
+          echo "   Tag: ${IMAGE_TAG}"
           echo "   Host: ${DEPLOYMENT_HOST}"
           echo "   Stack: ${STACK_PATH}"
           
+          # Validate that IMAGE_TAG is not empty
+          if [ -z "$IMAGE_TAG" ] || [ "$IMAGE_TAG" = "..." ]; then
+            echo "❌ Error: IMAGE_TAG is empty or invalid: '${IMAGE_TAG}'"
+            exit 1
+          fi
+          
           # SSH with proper key and execute deployment commands
           ssh -i ~/.ssh/production \
               -o StrictHostKeyChecking=no \