Add Message, MessageMut, MessageView traits.

PiperOrigin-RevId: 652916543

rust/BUILD

@@ -47,6 +47,7 @@ rust_library(
 #
 # shared.rs is the root of the crate and has public items re-exported in protobuf.rs for user use.
 PROTOBUF_SHARED = [
+    "codegen_traits.rs",
     "enum.rs",
     "internal.rs",
     "primitive.rs",

rust/codegen_traits.rs

@@ -0,0 +1,17 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2024 Google LLC.  All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+
+//! Traits that are implemeted by codegen types.
+
+use crate::Proxied;
+use std::fmt::Debug;
+
+pub trait Message: Default + Debug + Proxied + Send + Sync {}
+
+pub trait MessageView: Debug + Send + Sync {}
+
+pub trait MessageMut: Debug + Sync {}

rust/shared.rs

@@ -22,6 +22,7 @@ use std::fmt;
 /// These are the items protobuf users can access directly.
 #[doc(hidden)]
 pub mod __public {
+    pub use crate::codegen_traits::{Message, MessageMut, MessageView};
     pub use crate::r#enum::{Enum, UnknownEnumValue};
     pub use crate::map::{Map, MapIter, MapMut, MapView, ProxiedInMapValue};
     pub use crate::optional::Optional;
@@ -51,6 +52,7 @@ pub mod __runtime;
 #[path = "upb.rs"]
 pub mod __runtime;
 
+mod codegen_traits;
 #[path = "enum.rs"]
 mod r#enum;
 mod map;

src/google/protobuf/compiler/rust/message.cc

@@ -951,6 +951,8 @@ void GenerateRs(Context& ctx, const Descriptor& msg) {
           inner: $pbr$::MessageInner
         }
 
+        impl $pb$::Message for $Msg$ {}
+
         impl std::fmt::Debug for $Msg$ {
           fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             $Msg::debug$
@@ -988,6 +990,8 @@ void GenerateRs(Context& ctx, const Descriptor& msg) {
           _phantom: $Phantom$<&'msg ()>,
         }
 
+        impl $pb$::MessageView for $Msg$View<'_> {}
+
         impl std::fmt::Debug for $Msg$View<'_> {
           fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             $Msg::debug$
@@ -1047,6 +1051,8 @@ void GenerateRs(Context& ctx, const Descriptor& msg) {
           inner: $pbr$::MutatorMessageRef<'msg>,
         }
 
+        impl $pb$::MessageMut for $Msg$Mut<'_> {}
+
         impl std::fmt::Debug for $Msg$Mut<'_> {
           fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             $Msg::debug$