Assuming I have a simple struct:
message TestMessage {
optional int64 i64 = 1 [(gogoproto.nullable) = false];
optional uint64 u64 = 2 [(gogoproto.nullable) = false];
optional int32 i32 = 3 [(gogoproto.nullable) = false];
optional uint32 u32 = 4 [(gogoproto.nullable) = false];
optional double f64 = 5 [(gogoproto.nullable) = false];
optional string str = 6 [(gogoproto.nullable) = false];
optional bool bol = 7 [(gogoproto.nullable) = false];
}Which then results in:
type TestMessage struct {
I64 int64 `protobuf:"varint,1,opt,name=i64" json:"i64"`
U64 uint64 `protobuf:"varint,2,opt,name=u64" json:"u64"`
I32 int32 `protobuf:"varint,3,opt,name=i32" json:"i32"`
U32 uint32 `protobuf:"varint,4,opt,name=u32" json:"u32"`
F64 float64 `protobuf:"fixed64,5,opt,name=f64" json:"f64"`
Str string `protobuf:"bytes,6,opt,name=str" json:"str"`
Bol bool `protobuf:"varint,7,opt,name=bol" json:"bol"`
}
func (m *TestMessage) Reset() { *m = TestMessage{} }
func (*TestMessage) ProtoMessage() {}As you can see, all attributes are optional and non-nullable. If I then marshal the struct, I get something like:
pb, _ := proto.Marshal(&TestMessage{})
fmt.Println(pb)
var msg TestMessage
if proto.Unmarshal(pb, &msg) == nil {
fmt.Println(msg)
}
// Output:
// [8 0 16 0 24 0 32 0 41 0 0 0 0 0 0 0 0 50 0]
// {0 0 0 0 0 false} This is obviously quite a waste and not in line with how Go works. I understand that protobuf generated by Go messages must be interoperable but it would be nice to have the option to omit zero values. I have applied a manual patch below for now, but is this a feature you would generally consider?
Here's the output with the patch:
// []
// {0 0 0 0 0 false} Here's the patched code:
diff --git a/proto/encode_gogo.go b/proto/encode_gogo.go
index f77cfb1..aa99d86 100644
--- a/proto/encode_gogo.go
+++ b/proto/encode_gogo.go
@@ -36,9 +36,7 @@
package proto
-import (
- "reflect"
-)
+import "reflect"
func NewRequiredNotSetError(field string) *RequiredNotSetError {
return &RequiredNotSetError{field}
@@ -69,6 +67,9 @@ func size_ext_slice_byte(p *Properties, base structPointer) (n int) {
// Encode a reference to bool pointer.
func (o *Buffer) enc_ref_bool(p *Properties, base structPointer) error {
v := *structPointer_BoolVal(base, p.field)
+ if !v && p.Optional {
+ return ErrNil
+ }
x := 0
if v {
x = 1
@@ -79,6 +80,10 @@ func (o *Buffer) enc_ref_bool(p *Properties, base structPointer) error {
}
func size_ref_bool(p *Properties, base structPointer) int {
+ v := *structPointer_BoolVal(base, p.field)
+ if !v && p.Optional {
+ return 0
+ }
return len(p.tagcode) + 1 // each bool takes exactly one byte
}
@@ -86,6 +91,9 @@ func size_ref_bool(p *Properties, base structPointer) int {
func (o *Buffer) enc_ref_int32(p *Properties, base structPointer) error {
v := structPointer_Word32Val(base, p.field)
x := int32(word32Val_Get(v))
+ if x == 0 && p.Optional {
+ return ErrNil
+ }
o.buf = append(o.buf, p.tagcode...)
p.valEnc(o, uint64(x))
return nil
@@ -94,6 +102,9 @@ func (o *Buffer) enc_ref_int32(p *Properties, base structPointer) error {
func size_ref_int32(p *Properties, base structPointer) (n int) {
v := structPointer_Word32Val(base, p.field)
x := int32(word32Val_Get(v))
+ if x == 0 && p.Optional {
+ return
+ }
n += len(p.tagcode)
n += p.valSize(uint64(x))
return
@@ -102,6 +113,9 @@ func size_ref_int32(p *Properties, base structPointer) (n int) {
func (o *Buffer) enc_ref_uint32(p *Properties, base structPointer) error {
v := structPointer_Word32Val(base, p.field)
x := word32Val_Get(v)
+ if x == 0 && p.Optional {
+ return ErrNil
+ }
o.buf = append(o.buf, p.tagcode...)
p.valEnc(o, uint64(x))
return nil
@@ -110,6 +124,9 @@ func (o *Buffer) enc_ref_uint32(p *Properties, base structPointer) error {
func size_ref_uint32(p *Properties, base structPointer) (n int) {
v := structPointer_Word32Val(base, p.field)
x := word32Val_Get(v)
+ if x == 0 && p.Optional {
+ return
+ }
n += len(p.tagcode)
n += p.valSize(uint64(x))
return
@@ -119,6 +136,10 @@ func size_ref_uint32(p *Properties, base structPointer) (n int) {
func (o *Buffer) enc_ref_int64(p *Properties, base structPointer) error {
v := structPointer_Word64Val(base, p.field)
x := word64Val_Get(v)
+ if x == 0 && p.Optional {
+ return ErrNil
+ }
+
o.buf = append(o.buf, p.tagcode...)
p.valEnc(o, x)
return nil
@@ -127,6 +148,10 @@ func (o *Buffer) enc_ref_int64(p *Properties, base structPointer) error {
func size_ref_int64(p *Properties, base structPointer) (n int) {
v := structPointer_Word64Val(base, p.field)
x := word64Val_Get(v)
+ if x == 0 && p.Optional {
+ return
+ }
+
n += len(p.tagcode)
n += p.valSize(x)
return
@@ -135,6 +160,10 @@ func size_ref_int64(p *Properties, base structPointer) (n int) {
// Encode a reference to a string pointer.
func (o *Buffer) enc_ref_string(p *Properties, base structPointer) error {
v := *structPointer_StringVal(base, p.field)
+ if v == "" && p.Optional {
+ return ErrNil
+ }
+
o.buf = append(o.buf, p.tagcode...)
o.EncodeStringBytes(v)
return nil
@@ -142,6 +171,9 @@ func (o *Buffer) enc_ref_string(p *Properties, base structPointer) error {
func size_ref_string(p *Properties, base structPointer) (n int) {
v := *structPointer_StringVal(base, p.field)
+ if v == "" && p.Optional {
+ return
+ }
n += len(p.tagcode)
n += sizeStringBytes(v)
return
Assuming I have a simple struct:
Which then results in:
As you can see, all attributes are optional and non-nullable. If I then marshal the struct, I get something like:
This is obviously quite a waste and not in line with how Go works. I understand that protobuf generated by Go messages must be interoperable but it would be nice to have the option to omit zero values. I have applied a manual patch below for now, but is this a feature you would generally consider?
Here's the output with the patch:
Here's the patched code: