proto: check for required fields in encoding/decoding

Change-Id: I0555a92e0399782f075b1dcd248e880dd48c7d6d
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/170579
Reviewed-by: Herbie Ong <herbie@google.com>
diff --git a/encoding/textpb/decode.go b/encoding/textpb/decode.go
index 38b512e..731ee64 100644
--- a/encoding/textpb/decode.go
+++ b/encoding/textpb/decode.go
@@ -503,7 +503,10 @@
 		return err
 	}
 	// Serialize the embedded message and assign the resulting bytes to the value field.
-	b, err := proto.MarshalOptions{Deterministic: true}.Marshal(m.Interface())
+	b, err := proto.MarshalOptions{
+		AllowPartial:  o.AllowPartial,
+		Deterministic: true,
+	}.Marshal(m.Interface())
 	if !nerr.Merge(err) {
 		return err
 	}
diff --git a/encoding/textpb/decode_test.go b/encoding/textpb/decode_test.go
index 2f14029..7c45641 100644
--- a/encoding/textpb/decode_test.go
+++ b/encoding/textpb/decode_test.go
@@ -1405,9 +1405,10 @@
 			m := &pb2.PartialRequired{
 				OptString: scalar.String("embedded inside Any"),
 			}
-			b, err := proto.MarshalOptions{Deterministic: true}.Marshal(m)
-			// TODO: Marshal may fail due to required field not set at some
-			// point. Need to ignore required not set error here.
+			b, err := proto.MarshalOptions{
+				AllowPartial:  true,
+				Deterministic: true,
+			}.Marshal(m)
 			if err != nil {
 				t.Fatalf("error in binary marshaling message for Any.value: %v", err)
 			}
diff --git a/encoding/textpb/encode.go b/encoding/textpb/encode.go
index 4fd5d7d..2ea370f 100644
--- a/encoding/textpb/encode.go
+++ b/encoding/textpb/encode.go
@@ -353,7 +353,9 @@
 	}
 	em := emt.New().Interface()
 	// TODO: Need to set types registry in binary unmarshaling.
-	err = proto.Unmarshal(value.Bytes(), em)
+	err = proto.UnmarshalOptions{
+		AllowPartial: o.AllowPartial,
+	}.Unmarshal(value.Bytes(), em)
 	if !nerr.Merge(err) {
 		return text.Value{}, err
 	}
diff --git a/encoding/textpb/encode_test.go b/encoding/textpb/encode_test.go
index c929549..5b9ee38 100644
--- a/encoding/textpb/encode_test.go
+++ b/encoding/textpb/encode_test.go
@@ -1160,9 +1160,10 @@
 			m := &pb2.PartialRequired{
 				OptString: scalar.String("embedded inside Any"),
 			}
-			b, err := proto.MarshalOptions{Deterministic: true}.Marshal(m)
-			// TODO: Marshal may fail due to required field not set at some
-			// point. Need to ignore required not set error here.
+			b, err := proto.MarshalOptions{
+				AllowPartial:  true,
+				Deterministic: true,
+			}.Marshal(m)
 			if err != nil {
 				t.Fatalf("error in binary marshaling message for Any.value: %v", err)
 			}