Introduce staticcheck for stricter builds (#7035)

cmd/gateway/azure/gateway-azure.go

@@ -740,6 +740,9 @@ func (a *azureObjects) PutObject(ctx context.Context, bucket, object string, r *
 	if data.Size() < azureBlockSize/10 {
 		blob := a.client.GetContainerReference(bucket).GetBlobReference(object)
 		blob.Metadata, blob.Properties, err = s3MetaToAzureProperties(ctx, opts.UserDefined)
+		if err != nil {
+			return objInfo, azureToObjectError(err, bucket, object)
+		}
 		if err = blob.CreateBlockBlobFromReader(data, nil); err != nil {
 			return objInfo, azureToObjectError(err, bucket, object)
 		}

cmd/gateway/gcs/gateway-gcs.go

@@ -888,6 +888,7 @@ func (l *gcsGateway) PutObject(ctx context.Context, bucket string, key string, r
 	object := l.client.Bucket(bucket).Object(key)
 
 	w := object.NewWriter(ctx)
+
 	// Disable "chunked" uploading in GCS client if the size of the data to be uploaded is below
 	// the current chunk-size of the writer. This avoids an unnecessary memory allocation.
 	if data.Size() < int64(w.ChunkSize) {

cmd/gateway/oss/gateway-oss_test.go

@@ -111,9 +111,8 @@ func TestOSSToObjectError(t *testing.T) {
 
 func TestS3MetaToOSSOptions(t *testing.T) {
 	var err error
-	var headers map[string]string
 
-	headers = map[string]string{
+	headers := map[string]string{
 		"x-amz-meta-invalid_meta": "value",
 	}
 	_, err = appendS3MetaToOSSOptions(context.Background(), nil, headers)