Normalize dockerfile paths for build and bake

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

@@ -148,10 +148,33 @@ jobs:
             done <<< "$BUILD_ARGS"
           fi
 
+          normalize_path() {
+            local p="$1"
+            while [[ "$p" == ./* ]]; do
+              p="${p#./}"
+            done
+            if [ "$p" != "/" ]; then
+              p="${p%/}"
+            fi
+            printf '%s' "$p"
+          }
+
           while read -r group; do
             GROUP_COUNT=$(echo "$group" | jq 'length')
             CONTEXT=$(echo "$group" | jq -r '.[0].context')
             DOCKERFILE=$(echo "$group" | jq -r '.[0].dockerfile')
+            context_norm="$(normalize_path "$CONTEXT")"
+            dockerfile_norm="$(normalize_path "$DOCKERFILE")"
+            DOCKERFILE_FOR_BAKE="$DOCKERFILE"
+            DOCKERFILE_FOR_BUILD="$DOCKERFILE"
+            if [ -n "$context_norm" ] && [ "$context_norm" != "." ]; then
+              if [[ "$dockerfile_norm" == "$context_norm/"* ]]; then
+                DOCKERFILE_FOR_BAKE="${dockerfile_norm#$context_norm/}"
+                DOCKERFILE_FOR_BUILD="$dockerfile_norm"
+              elif [[ "$dockerfile_norm" != /* ]]; then
+                DOCKERFILE_FOR_BUILD="${context_norm}/${dockerfile_norm}"
+              fi
+            fi
 
             if [ "$GROUP_COUNT" -gt 1 ]; then
               echo "==== Building $GROUP_COUNT images from $DOCKERFILE (bake) ===="
@@ -191,7 +214,7 @@ jobs:
 
                 TARGET_OBJ=$(jq -n \
                   --arg context "$CONTEXT" \
-                  --arg dockerfile "$DOCKERFILE" \
+                  --arg dockerfile "$DOCKERFILE_FOR_BAKE" \
                   --arg target "$TARGET" \
                   --argjson tags "$TAGS_JSON" \
                   --argjson args "$BUILD_ARGS_JSON" \
@@ -264,7 +287,7 @@ jobs:
               echo "==== Building $FULL_IMAGE ===="
 
               docker buildx build \
-                --file "$DOCKERFILE" \
+                --file "$DOCKERFILE_FOR_BUILD" \
                 "${TARGET_FLAGS[@]}" \
                 "${CACHE_FLAGS[@]}" \
                 "${SSH_FLAGS[@]}" \