internal/legacy: extract legacy support out from the impl package
The impl package currently supports wrapping legacy v1 enums and messages
so that they implement the v2 reflective APIs. This functionality is necessary
for v1 and v2 to interoperate. However, the existence of this functionality
presents several problems:
* A significant portion of the complexity in impl is for legacy wrapping.
* This complexity is linked into a Go binary even if all the other messages
in the binary natively support v2 reflection.
* It presents a cyclic dependency when trying to generate descriptor proto.
Suppose you are generating descriptor.proto. The generated code would want to
depend on the impl package because impl is the runtime implementation for
protobuf messages. However, impl currently depends depends on descriptor in
order to wrap legacy enum and messages since it needs the ability to dynamically
create new protobuf descriptor types. In the case of descriptor.proto, it would
presumably be generated with native reflection support, so the legacy wrapping
logic is unneccessary.
To break the dependency of impl on descriptor, we move the legacy support logic
to a different package and instead add hooks in impl so that legacy support could
be dynamically registered at runtime. This is dependency injection.
Change-Id: I01a582908ed5629993f6699e9bf2f4bee93857a4
Reviewed-on: https://go-review.googlesource.com/c/151877
Reviewed-by: Herbie Ong <herbie@google.com>
diff --git a/internal/impl/message_test.go b/internal/impl/message_test.go
index eeb4e7a..d388494 100644
--- a/internal/impl/message_test.go
+++ b/internal/impl/message_test.go
@@ -2,7 +2,7 @@
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
-package impl
+package impl_test
import (
"fmt"
@@ -12,14 +12,19 @@
protoV1 "github.com/golang/protobuf/proto"
descriptorV1 "github.com/golang/protobuf/protoc-gen-go/descriptor"
+ pimpl "github.com/golang/protobuf/v2/internal/impl"
scalar "github.com/golang/protobuf/v2/internal/scalar"
+ pvalue "github.com/golang/protobuf/v2/internal/value"
pref "github.com/golang/protobuf/v2/reflect/protoreflect"
ptype "github.com/golang/protobuf/v2/reflect/prototype"
cmp "github.com/google/go-cmp/cmp"
cmpopts "github.com/google/go-cmp/cmp/cmpopts"
+ // The legacy package must be imported prior to use of any legacy messages.
+ // TODO: Remove this when protoV1 registers these hooks for you.
+ _ "github.com/golang/protobuf/v2/internal/legacy"
+
proto2_20180125 "github.com/golang/protobuf/v2/internal/testprotos/legacy/proto2.v1.0.0-20180125-92554152"
- pvalue "github.com/golang/protobuf/v2/internal/value"
)
// List of test operations to perform on messages, lists, or maps.
@@ -184,7 +189,7 @@
MapBytes map[MyString]MyBytes
)
-var scalarProto2Type = MessageType{Type: ptype.GoMessage(
+var scalarProto2Type = pimpl.MessageType{Type: ptype.GoMessage(
mustMakeMessageDesc(ptype.StandaloneMessage{
Syntax: pref.Proto2,
FullName: "ScalarProto2",
@@ -279,7 +284,7 @@
MyBytesA MyString `protobuf:"22"`
}
-var scalarProto3Type = MessageType{Type: ptype.GoMessage(
+var scalarProto3Type = pimpl.MessageType{Type: ptype.GoMessage(
mustMakeMessageDesc(ptype.StandaloneMessage{
Syntax: pref.Proto3,
FullName: "ScalarProto3",
@@ -387,7 +392,7 @@
MyBytes4 ListStrings `protobuf:"19"`
}
-var listScalarsType = MessageType{Type: ptype.GoMessage(
+var listScalarsType = pimpl.MessageType{Type: ptype.GoMessage(
mustMakeMessageDesc(ptype.StandaloneMessage{
Syntax: pref.Proto2,
FullName: "ListScalars",
@@ -565,7 +570,7 @@
}
}
-var mapScalarsType = MessageType{Type: ptype.GoMessage(
+var mapScalarsType = pimpl.MessageType{Type: ptype.GoMessage(
mustMakeMessageDesc(ptype.StandaloneMessage{
Syntax: pref.Proto2,
FullName: "MapScalars",
@@ -732,7 +737,7 @@
Union isOneofScalars_Union `protobuf_oneof:"union"`
}
-var oneofScalarsType = MessageType{Type: ptype.GoMessage(
+var oneofScalarsType = pimpl.MessageType{Type: ptype.GoMessage(
mustMakeMessageDesc(ptype.StandaloneMessage{
Syntax: pref.Proto2,
FullName: "OneofScalars",
@@ -933,14 +938,14 @@
Union isEnumMessages_Union `protobuf_oneof:"union"`
}
-var enumMessagesType = MessageType{Type: ptype.GoMessage(
+var enumMessagesType = pimpl.MessageType{Type: ptype.GoMessage(
mustMakeMessageDesc(ptype.StandaloneMessage{
Syntax: pref.Proto2,
FullName: "EnumMessages",
Fields: []ptype.Field{
{Name: "f1", Number: 1, Cardinality: pref.Optional, Kind: pref.EnumKind, Default: V("BEEF"), EnumType: enumProto2Type},
{Name: "f2", Number: 2, Cardinality: pref.Optional, Kind: pref.EnumKind, Default: V("BRAVO"), EnumType: enumProto3Type},
- {Name: "f3", Number: 3, Cardinality: pref.Optional, Kind: pref.MessageKind, MessageType: MessageOf(new(proto2_20180125.Message)).Type()},
+ {Name: "f3", Number: 3, Cardinality: pref.Optional, Kind: pref.MessageKind, MessageType: pimpl.Export{}.MessageOf(new(proto2_20180125.Message)).Type()},
{Name: "f4", Number: 4, Cardinality: pref.Optional, Kind: pref.MessageKind, MessageType: ptype.PlaceholderMessage("EnumMessages")},
{Name: "f5", Number: 5, Cardinality: pref.Repeated, Kind: pref.EnumKind, EnumType: enumProto2Type},
{Name: "f6", Number: 6, Cardinality: pref.Repeated, Kind: pref.MessageKind, MessageType: scalarProto2Type.Type},
@@ -1018,7 +1023,7 @@
func (*EnumMessages_OneofM3) isEnumMessages_Union() {}
func TestEnumMessages(t *testing.T) {
- wantL := MessageOf(&proto2_20180125.Message{OptionalFloat: scalar.Float32(math.E)})
+ wantL := pimpl.Export{}.MessageOf(&proto2_20180125.Message{OptionalFloat: scalar.Float32(math.E)})
wantM := &EnumMessages{EnumP2: EnumProto2(1234).Enum()}
wantM2a := &ScalarProto2{Float32: scalar.Float32(math.Pi)}
wantM2b := &ScalarProto2{Float32: scalar.Float32(math.Phi)}