Merge from google internal

1 files changed, 6 insertions, 0 deletions

diff --git a/src/google/protobuf/field_mask.proto b/src/google/protobuf/field_mask.proto
index c68d247c..eb96ba00 100644
--- a/src/google/protobuf/field_mask.proto
+++ b/src/google/protobuf/field_mask.proto
@@ -240,6 +240,12 @@ option go_package = "google.golang.org/genproto/protobuf/field_mask;field_mask";
 //
 // Note that oneof type names ("test_oneof" in this case) cannot be used in
 // paths.
+//
+// ## Field Mask Verification
+//
+// The implementation of the all the API methods, which have any FieldMask type
+// field in the request, should verify the included field paths, and return
+// `INVALID_ARGUMENT` error if any path is duplicated or unmappable.
 message FieldMask {
   // The set of field mask paths.
   repeated string paths = 1;