mirror of
https://github.com/protocolbuffers/protobuf-go.git
synced 2025-04-17 02:42:35 +00:00
proto: remove shallow merge support, and MergeOptions
We're still debating what the semantics of shallow merges should be, and what the use case for them (if any) is. There's no need to commit ourselves to this feature at this time; drop it for now. Remove the exported MergeOptions type, since the only option is gone. We can trivially add it back in the future if we need it. Change-Id: I4c8697cae69cc66eed1ea65de84b982f20e1be44 Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/219145 Reviewed-by: Joe Tsai <joetsai@google.com>
This commit is contained in:
Damien Neil
parent
316febd1ab
commit
cf33a9a274
155
proto/merge.go
155
proto/merge.go
@ -5,71 +5,9 @@
|
||||
package proto
|
||||
|
||||
import (
|
||||
"google.golang.org/protobuf/internal/pragma"
|
||||
"google.golang.org/protobuf/reflect/protoreflect"
|
||||
)
|
||||
|
||||
// MergeOptions configures the merger.
|
||||
//
|
||||
// Example usage:
|
||||
// MergeOptions{Shallow: true}.Merge(dst, src)
|
||||
type MergeOptions struct {
|
||||
pragma.NoUnkeyedLiterals
|
||||
|
||||
// Shallow configures Merge to shallow copy messages, lists, and maps
|
||||
// instead of allocating new ones in the destination if it does not already
|
||||
// have one populated. Scalar bytes are copied by reference.
|
||||
// If true, Merge must be given messages of the same concrete type.
|
||||
//
|
||||
// If false, Merge is guaranteed to produce deep copies of all mutable
|
||||
// objects from the source into the destination. Since scalar bytes are
|
||||
// mutable they are deep copied as a result.
|
||||
//
|
||||
// Invariant:
|
||||
// var dst1, dst2 Message = ...
|
||||
// Equal(dst1, dst2) // assume equal initially
|
||||
// MergeOptions{Shallow: true}.Merge(dst1, src)
|
||||
// MergeOptions{Shallow: false}.Merge(dst2, src)
|
||||
// Equal(dst1, dst2) // equal regardless of whether Shallow is specified
|
||||
Shallow bool
|
||||
}
|
||||
|
||||
// Clone returns a deep copy of m.
|
||||
// See MergeOptions.Clone for details.
|
||||
func Clone(m Message) Message {
|
||||
return MergeOptions{}.Clone(m)
|
||||
}
|
||||
|
||||
// Merge merges src into dst, which must be messages with the same descriptor.
|
||||
// See MergeOptions.Merge for details.
|
||||
func Merge(dst, src Message) {
|
||||
MergeOptions{}.Merge(dst, src)
|
||||
}
|
||||
|
||||
// Clone returns a copy of m.
|
||||
// If Shallow is specified it makes a new message and shallow copies m into it.
|
||||
// If the top-level message is invalid, it returns an invalid message as well.
|
||||
func (o MergeOptions) Clone(m Message) Message {
|
||||
// NOTE: Most usages of Clone assume the following properties:
|
||||
// t := reflect.TypeOf(m)
|
||||
// t == reflect.TypeOf(m.ProtoReflect().New().Interface())
|
||||
// t == reflect.TypeOf(m.ProtoReflect().Type().Zero().Interface())
|
||||
//
|
||||
// Embedding protobuf messages breaks this since the parent type will have
|
||||
// a forwarded ProtoReflect method, but the Interface method will return
|
||||
// the underlying embedded message type.
|
||||
return o.cloneMessage(m.ProtoReflect()).Interface()
|
||||
}
|
||||
|
||||
func (o MergeOptions) cloneMessage(src protoreflect.Message) (dst protoreflect.Message) {
|
||||
if !src.IsValid() {
|
||||
return src.Type().Zero()
|
||||
}
|
||||
dst = src.New()
|
||||
o.mergeMessage(dst, src)
|
||||
return dst
|
||||
}
|
||||
|
||||
// Merge merges src into dst, which must be messages with the same descriptor.
|
||||
//
|
||||
// Populated scalar fields in src are copied to dst, while populated
|
||||
@ -81,41 +19,47 @@ func (o MergeOptions) cloneMessage(src protoreflect.Message) (dst protoreflect.M
|
||||
//
|
||||
// It is semantically equivalent to unmarshaling the encoded form of src
|
||||
// into dst with the UnmarshalOptions.Merge option specified.
|
||||
func (o MergeOptions) Merge(dst, src Message) {
|
||||
func Merge(dst, src Message) {
|
||||
dstMsg, srcMsg := dst.ProtoReflect(), src.ProtoReflect()
|
||||
if o.Shallow {
|
||||
if dstMsg.Type() != srcMsg.Type() {
|
||||
panic("type mismatch")
|
||||
}
|
||||
} else {
|
||||
if dstMsg.Descriptor() != srcMsg.Descriptor() {
|
||||
panic("descriptor mismatch")
|
||||
}
|
||||
if dstMsg.Descriptor() != srcMsg.Descriptor() {
|
||||
panic("descriptor mismatch")
|
||||
}
|
||||
o.mergeMessage(dstMsg, srcMsg)
|
||||
mergeOptions{}.mergeMessage(dstMsg, srcMsg)
|
||||
}
|
||||
|
||||
func (o MergeOptions) mergeMessage(dst, src protoreflect.Message) {
|
||||
// Clone returns a copy of m.
|
||||
// If the top-level message is invalid, it returns an invalid message as well.
|
||||
func Clone(m Message) Message {
|
||||
// NOTE: Most usages of Clone assume the following properties:
|
||||
// t := reflect.TypeOf(m)
|
||||
// t == reflect.TypeOf(m.ProtoReflect().New().Interface())
|
||||
// t == reflect.TypeOf(m.ProtoReflect().Type().Zero().Interface())
|
||||
//
|
||||
// Embedding protobuf messages breaks this since the parent type will have
|
||||
// a forwarded ProtoReflect method, but the Interface method will return
|
||||
// the underlying embedded message type.
|
||||
src := m.ProtoReflect()
|
||||
if !src.IsValid() {
|
||||
return src.Type().Zero().Interface()
|
||||
}
|
||||
dst := src.New()
|
||||
mergeOptions{}.mergeMessage(dst, src)
|
||||
return dst.Interface()
|
||||
}
|
||||
|
||||
// mergeOptions provides a namespace for merge functions, and can be
|
||||
// exported in the future if we add user-visible merge options.
|
||||
type mergeOptions struct{}
|
||||
|
||||
func (o mergeOptions) mergeMessage(dst, src protoreflect.Message) {
|
||||
src.Range(func(fd protoreflect.FieldDescriptor, v protoreflect.Value) bool {
|
||||
switch {
|
||||
case fd.IsList():
|
||||
if o.Shallow && !dst.Has(fd) {
|
||||
dst.Set(fd, v)
|
||||
} else {
|
||||
o.mergeList(dst.Mutable(fd).List(), v.List(), fd)
|
||||
}
|
||||
o.mergeList(dst.Mutable(fd).List(), v.List(), fd)
|
||||
case fd.IsMap():
|
||||
if o.Shallow && !dst.Has(fd) {
|
||||
dst.Set(fd, v)
|
||||
} else {
|
||||
o.mergeMap(dst.Mutable(fd).Map(), v.Map(), fd.MapValue())
|
||||
}
|
||||
o.mergeMap(dst.Mutable(fd).Map(), v.Map(), fd.MapValue())
|
||||
case fd.Message() != nil:
|
||||
if o.Shallow && !dst.Has(fd) {
|
||||
dst.Set(fd, v)
|
||||
} else {
|
||||
o.mergeMessage(dst.Mutable(fd).Message(), v.Message())
|
||||
}
|
||||
o.mergeMessage(dst.Mutable(fd).Message(), v.Message())
|
||||
case fd.Kind() == protoreflect.BytesKind:
|
||||
dst.Set(fd, o.cloneBytes(v))
|
||||
default:
|
||||
@ -125,26 +69,18 @@ func (o MergeOptions) mergeMessage(dst, src protoreflect.Message) {
|
||||
})
|
||||
|
||||
if len(src.GetUnknown()) > 0 {
|
||||
if o.Shallow && dst.GetUnknown() == nil {
|
||||
dst.SetUnknown(src.GetUnknown())
|
||||
} else {
|
||||
dst.SetUnknown(append(dst.GetUnknown(), src.GetUnknown()...))
|
||||
}
|
||||
dst.SetUnknown(append(dst.GetUnknown(), src.GetUnknown()...))
|
||||
}
|
||||
}
|
||||
|
||||
func (o MergeOptions) mergeList(dst, src protoreflect.List, fd protoreflect.FieldDescriptor) {
|
||||
func (o mergeOptions) mergeList(dst, src protoreflect.List, fd protoreflect.FieldDescriptor) {
|
||||
// Merge semantics appends to the end of the existing list.
|
||||
for i, n := 0, src.Len(); i < n; i++ {
|
||||
switch v := src.Get(i); {
|
||||
case fd.Message() != nil:
|
||||
if o.Shallow {
|
||||
dst.Append(v)
|
||||
} else {
|
||||
dstv := dst.NewElement()
|
||||
o.mergeMessage(dstv.Message(), v.Message())
|
||||
dst.Append(dstv)
|
||||
}
|
||||
dstv := dst.NewElement()
|
||||
o.mergeMessage(dstv.Message(), v.Message())
|
||||
dst.Append(dstv)
|
||||
case fd.Kind() == protoreflect.BytesKind:
|
||||
dst.Append(o.cloneBytes(v))
|
||||
default:
|
||||
@ -153,18 +89,14 @@ func (o MergeOptions) mergeList(dst, src protoreflect.List, fd protoreflect.Fiel
|
||||
}
|
||||
}
|
||||
|
||||
func (o MergeOptions) mergeMap(dst, src protoreflect.Map, fd protoreflect.FieldDescriptor) {
|
||||
func (o mergeOptions) mergeMap(dst, src protoreflect.Map, fd protoreflect.FieldDescriptor) {
|
||||
// Merge semantics replaces, rather than merges into existing entries.
|
||||
src.Range(func(k protoreflect.MapKey, v protoreflect.Value) bool {
|
||||
switch {
|
||||
case fd.Message() != nil:
|
||||
if o.Shallow {
|
||||
dst.Set(k, v)
|
||||
} else {
|
||||
dstv := dst.NewValue()
|
||||
o.mergeMessage(dstv.Message(), v.Message())
|
||||
dst.Set(k, dstv)
|
||||
}
|
||||
dstv := dst.NewValue()
|
||||
o.mergeMessage(dstv.Message(), v.Message())
|
||||
dst.Set(k, dstv)
|
||||
case fd.Kind() == protoreflect.BytesKind:
|
||||
dst.Set(k, o.cloneBytes(v))
|
||||
default:
|
||||
@ -174,9 +106,6 @@ func (o MergeOptions) mergeMap(dst, src protoreflect.Map, fd protoreflect.FieldD
|
||||
})
|
||||
}
|
||||
|
||||
func (o MergeOptions) cloneBytes(v protoreflect.Value) protoreflect.Value {
|
||||
if o.Shallow {
|
||||
return v
|
||||
}
|
||||
func (o mergeOptions) cloneBytes(v protoreflect.Value) protoreflect.Value {
|
||||
return protoreflect.ValueOfBytes(append([]byte{}, v.Bytes()...))
|
||||
}
|
||||
|
||||
@ -17,12 +17,6 @@ import (
|
||||
)
|
||||
|
||||
func TestMerge(t *testing.T) {
|
||||
|
||||
t.Run("Deep", func(t *testing.T) { testMerge(t, false) })
|
||||
t.Run("Shallow", func(t *testing.T) { testMerge(t, true) })
|
||||
}
|
||||
|
||||
func testMerge(t *testing.T, shallow bool) {
|
||||
tests := []struct {
|
||||
desc string
|
||||
dst proto.Message
|
||||
@ -372,15 +366,13 @@ func testMerge(t *testing.T, shallow bool) {
|
||||
t.Fatalf("Unmarshal(Marshal(dst)+Marshal(src)) mismatch: got %v, want %v", dst, tt.want)
|
||||
}
|
||||
|
||||
proto.MergeOptions{Shallow: shallow}.Merge(tt.dst, tt.src)
|
||||
proto.Merge(tt.dst, tt.src)
|
||||
if !proto.Equal(tt.dst, tt.want) {
|
||||
t.Fatalf("Merge() mismatch:\n got %v\nwant %v", tt.dst, tt.want)
|
||||
}
|
||||
if tt.mutator != nil {
|
||||
wantObservable := tt.mutator(tt.src) && shallow
|
||||
gotObservable := !proto.Equal(tt.dst, tt.want)
|
||||
if gotObservable != wantObservable {
|
||||
t.Fatalf("mutation observed:\n got %v\nwant %v", gotObservable, wantObservable)
|
||||
if !proto.Equal(tt.dst, tt.want) {
|
||||
t.Fatalf("mutation observed in dest after modifying merge source:\n got %v\nwant %v", tt.dst, tt.want)
|
||||
}
|
||||
}
|
||||
})
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user