Multiple repeated fields are allowed (#1921)

* Multiple repeated fields are allowed

The protobuffer comments have been corrected here:
https://github.com/protocolbuffers/protobuf/blob/master/src/google/protobuf/field_mask.proto#L85-L86

The restriction was intended for the path string itself and not the
entire mask. There can be only one repeated field in a path string, and
when we get to it, the path string is done.

* Fixed test

* more test fixes

* fixed test

* fixed spaces/tabs

* Update fieldmask_test.go

Testing multiple repeated fields

* Update fieldmask_test.go

fixed test

* Update fieldmask_test.go

fixed indents

* Update fieldmask_test.go

* Update fieldmask_test.go

* Update fieldmask_test.go

* Update fieldmask_test.go

* Update fieldmask_test.go

Author: topherCantrell

runtime/fieldmask.go

@@ -32,7 +32,6 @@ func FieldMaskFromRequestBody(r io.Reader, msg proto.Message) (*field_mask.Field
 	}
 
 	queue := []fieldMaskPathItem{{node: root, msg: msg.ProtoReflect()}}
-	var repeatedChild *fieldMaskPathItem
 	for len(queue) > 0 {
 		// dequeue an item
 		item := queue[0]
@@ -74,14 +73,9 @@ func FieldMaskFromRequestBody(r io.Reader, msg proto.Message) (*field_mask.Field
 
 				switch {
 				case fd.IsList(), fd.IsMap():
-					if repeatedChild != nil {
-						// This is implied by the rule that any repeated fields must be
-						// last in the paths.
-						// Ref: https://github.com/protocolbuffers/protobuf/blob/6b0ff74ecf63e26c7315f6745de36aff66deb59d/src/google/protobuf/field_mask.proto#L85-L86
-						return nil, fmt.Errorf("only one repeated value is allowed per field_mask")
-					}
-					repeatedChild = &child
-					// Don't add to paths until the end
+					// As per: https://github.com/protocolbuffers/protobuf/blob/master/src/google/protobuf/field_mask.proto#L85-L86
+					// Do not recurse into repeated fields. The repeated field goes on the end of the path and we stop.
+					fm.Paths = append(fm.Paths, child.path)
 				case fd.Message() != nil:
 					child.msg = item.msg.Get(fd).Message()
 					fallthrough
@@ -95,12 +89,6 @@ func FieldMaskFromRequestBody(r io.Reader, msg proto.Message) (*field_mask.Field
 		}
 	}
 
-	// Add any repeated fields last, as per
-	// https://github.com/protocolbuffers/protobuf/blob/6b0ff74ecf63e26c7315f6745de36aff66deb59d/src/google/protobuf/field_mask.proto#L85-L86
-	if repeatedChild != nil {
-		fm.Paths = append(fm.Paths, repeatedChild.path)
-	}
-
 	return fm, nil
 }
 

runtime/fieldmask_test.go

@@ -182,11 +182,12 @@ func TestFieldMaskRepeatedFieldsLast(t *testing.T) {
 	}{
 		{
 			name:  "map",
-			input: `{"mapped_string_value": {"a": "x"}, "uuid":"1234"}`,
+			input: `{"mapped_string_value": {"a": "x"}, "repeated_string_value": {"b": "y"}, "uuid":"1234"}`,
 			expected: &field_mask.FieldMask{
 				Paths: []string{
-					"uuid",
 					"mapped_string_value",
+					"repeated_string_value",
+					"uuid",
 				},
 			},
 		},
@@ -204,12 +205,23 @@ func TestFieldMaskRepeatedFieldsLast(t *testing.T) {
 						"amount": 20
 					}
 				],
+				"nested_annotation": [
+					{
+						"name": "foo",
+						"amount": 100
+					},
+					{
+						"name": "widget",
+						"amount": 200
+					}
+				],
 				"uuid":"1234"
 			}`,
 			expected: &field_mask.FieldMask{
 				Paths: []string{
-					"uuid",
 					"nested",
+					"nested_annotation",
+					"uuid",
 				},
 			},
 		},