fix(http): handle invalid gzip stream errors (#9767)

* fix(http): handle invalid gzip stream errors

Explain:

- problem: ReadUrlAsStream could panic when a response claimed gzip encoding but the body was not a valid gzip stream.

- root cause: the gzip reader error was ignored and a nil reader was deferred and read from.

- fix: return the gzip.NewReader error before registering Close or reading.

- validation: go test ./weed/util/http -run TestReadUrlAsStreamReturnsGzipReaderError -count=1; git diff --check.

* test: avoid closing shared global HTTP client in unit test

weed/util/http/http_global_client_util.go

@@ -397,6 +397,9 @@ func ReadUrlAsStream(ctx context.Context, fileUrl, jwt string, cipherKey []byte,
 	switch contentEncoding {
 	case "gzip":
 		reader, err = gzip.NewReader(r.Body)
+		if err != nil {
+			return true, err
+		}
 		defer reader.Close()
 	default:
 		reader = r.Body

weed/util/http/http_global_client_util_test.go

@@ -1,6 +1,11 @@
 package http
 
-import "testing"
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
 
 func TestAppendQueryParameter(t *testing.T) {
 	testCases := []struct {
@@ -70,3 +75,19 @@ func TestAppendQueryParameter(t *testing.T) {
 		})
 	}
 }
+
+func TestReadUrlAsStreamReturnsGzipReaderError(t *testing.T) {
+	InitGlobalHttpClient()
+
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Encoding", "gzip")
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write([]byte("not gzip"))
+	}))
+	defer server.Close()
+
+	_, err := ReadUrlAsStream(context.Background(), server.URL, "", nil, false, true, 0, 0, func(data []byte) {})
+	if err == nil {
+		t.Fatal("ReadUrlAsStream returned nil error for invalid gzip response")
+	}
+}