fix: rewrite composite action using shell only (act_runner nested uses limitation)

.gitea/actions/docker-build/action.yml

@@ -1,8 +1,7 @@
 name: Docker Build & Push
 description: >
   Standard libreshop image build+push pipeline. Logs into the registry,
-  computes semver/branch/sha tags via metadata-action, builds and
-  optionally pushes the image.
+  computes branch/tag/sha tags, builds and optionally pushes the image.
 
 inputs:
   context:
@@ -33,42 +32,47 @@ runs:
   using: composite
   steps:
     - name: Set up Docker Buildx
-      uses: docker/setup-buildx-action@v3
+      shell: bash
+      run: docker buildx create --use 2>/dev/null || docker buildx use default 2>/dev/null || true
 
     - name: Log in to registry
       if: inputs.publish == 'true'
-      uses: docker/login-action@v3
-      with:
-        registry: ${{ inputs.registry }}
-        username: ${{ inputs.registry_user }}
-        password: ${{ inputs.registry_pass }}
+      shell: bash
+      run: |
+        echo "${{ inputs.registry_pass }}" | \
+          docker login "${{ inputs.registry }}" \
+            -u "${{ inputs.registry_user }}" --password-stdin
 
-    - name: Compute image name
-      id: name
+    - name: Build and push
       shell: bash
       run: |
         if [ -n "${{ inputs.image_name }}" ]; then
-          echo "value=${{ inputs.image_name }}" >> $GITHUB_OUTPUT
+          IMAGE="${{ inputs.image_name }}"
         else
-          echo "value=${{ inputs.registry }}/${{ github.repository }}" >> $GITHUB_OUTPUT
+          IMAGE="${{ inputs.registry }}/${{ github.repository }}"
         fi
 
-    - name: Compute tags and labels
-      id: meta
-      uses: docker/metadata-action@v5
-      with:
-        images: ${{ steps.name.outputs.value }}
-        tags: |
-          type=ref,event=branch
-          type=ref,event=tag
-          type=sha,prefix=sha-,format=short
-          type=raw,value=latest,enable=${{ startsWith(github.ref, 'refs/tags/') }}
+        REF="${{ github.ref }}"
+        SHA=$(echo "${{ github.sha }}" | cut -c1-7)
+        TAGS="-t ${IMAGE}:sha-${SHA}"
 
-    - name: Build and push
-      uses: docker/build-push-action@v6
-      with:
-        context: ${{ inputs.context }}
-        file: ${{ inputs.dockerfile }}
-        push: ${{ inputs.publish == 'true' }}
-        tags: ${{ steps.meta.outputs.tags }}
-        labels: ${{ steps.meta.outputs.labels }}
+        if [[ "${REF}" == refs/heads/* ]]; then
+          BRANCH="${REF#refs/heads/}"
+          TAGS="${TAGS} -t ${IMAGE}:${BRANCH}"
+        fi
+
+        if [[ "${REF}" == refs/tags/* ]]; then
+          TAG="${REF#refs/tags/}"
+          TAGS="${TAGS} -t ${IMAGE}:${TAG} -t ${IMAGE}:latest"
+        fi
+
+        PUSH_FLAG=""
+        if [ "${{ inputs.publish }}" = "true" ]; then
+          PUSH_FLAG="--push"
+        fi
+
+        docker buildx build \
+          --file "${{ inputs.dockerfile }}" \
+          ${TAGS} \
+          ${PUSH_FLAG} \
+          "${{ inputs.context }}"