Add merge_from to Msg and MsgMut codegen. Cpp Kernel uses new thunk to typed MergeFrom() and Upb Kernel uses new upb_Message_MergeFrom() function

PiperOrigin-RevId: 646961954

rust/test/shared/BUILD

@@ -362,6 +362,32 @@ rust_test(
     ],
 )
 
+rust_test(
+    name = "merge_from_cpp_test",
+    srcs = ["merge_from_test.rs"],
+    aliases = {
+        "//rust:protobuf_cpp": "protobuf",
+    },
+    deps = [
+        "//rust:protobuf_cpp",
+        "//rust/test:unittest_cpp_rust_proto",
+        "@crate_index//:googletest",
+    ],
+)
+
+rust_test(
+    name = "merge_from_upb_test",
+    srcs = ["merge_from_test.rs"],
+    aliases = {
+        "//rust:protobuf_upb": "protobuf",
+    },
+    deps = [
+        "//rust:protobuf_upb",
+        "//rust/test:unittest_upb_rust_proto",
+        "@crate_index//:googletest",
+    ],
+)
+
 rust_test(
     name = "proto_macro_cpp_test",
     srcs = ["proto_macro_test.rs"],

rust/test/shared/merge_from_test.rs

@@ -0,0 +1,54 @@
+use googletest::prelude::*;
+use protobuf::proto;
+use unittest_rust_proto::{NestedTestAllTypes, TestAllTypes};
+
+#[test]
+fn merge_from_empty() {
+    let mut dst = TestAllTypes::new();
+    let src = TestAllTypes::new();
+    dst.merge_from(src.as_view());
+    assert_that!(dst.as_view().has_optional_int32(), eq(false));
+}
+
+#[test]
+fn merge_from_non_empty() {
+    let mut dst = TestAllTypes::new();
+    let src = proto!(TestAllTypes { optional_int32: 42 });
+    dst.as_mut().merge_from(src.as_view());
+    assert_eq!(dst.as_view().optional_int32(), 42);
+}
+
+#[test]
+fn merge_repeated_empty() {
+    let mut dst = TestAllTypes::new();
+    let mut src = TestAllTypes::new();
+    src.repeated_int32_mut().extend(0..5);
+    dst.merge_from(src.as_view());
+    assert_that!(
+        &dst.repeated_int32().iter().collect::<Vec<_>>(),
+        eq(&src.repeated_int32().iter().collect::<Vec<_>>())
+    );
+}
+
+#[test]
+fn merge_repeated_non_empty() {
+    let mut dst = TestAllTypes::new();
+    let mut src = TestAllTypes::new();
+    dst.repeated_int32_mut().extend(0..5);
+    src.repeated_int32_mut().extend(5..10);
+    dst.merge_from(src.as_view());
+    assert_that!(
+        &dst.repeated_int32().iter().collect::<Vec<_>>(),
+        eq(&(0..10).collect::<Vec<_>>())
+    );
+}
+
+#[test]
+fn merge_from_sub_message() {
+    let mut dst = NestedTestAllTypes::new();
+    let src = proto!(NestedTestAllTypes {
+        child: NestedTestAllTypes { payload: TestAllTypes { optional_int32: 42 } }
+    });
+    dst.merge_from(src.as_view());
+    assert_that!(dst.as_view().child().payload().optional_int32(), eq(42));
+}

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

@@ -178,6 +178,7 @@ void MessageExterns(Context& ctx, const Descriptor& msg) {
               {"serialize_thunk", ThunkName(ctx, msg, "serialize")},
               {"parse_thunk", ThunkName(ctx, msg, "parse")},
               {"copy_from_thunk", ThunkName(ctx, msg, "copy_from")},
+              {"merge_from_thunk", ThunkName(ctx, msg, "merge_from")},
               {"repeated_len_thunk", ThunkName(ctx, msg, "repeated_len")},
               {"repeated_get_thunk", ThunkName(ctx, msg, "repeated_get")},
               {"repeated_get_mut_thunk",
@@ -195,6 +196,7 @@ void MessageExterns(Context& ctx, const Descriptor& msg) {
           fn $serialize_thunk$(raw_msg: $pbr$::RawMessage, out: &mut $pbr$::SerializedData) -> bool;
           fn $parse_thunk$(raw_msg: $pbr$::RawMessage, data: $pbr$::SerializedData) -> bool;
           fn $copy_from_thunk$(dst: $pbr$::RawMessage, src: $pbr$::RawMessage);
+          fn $merge_from_thunk$(dst: $pbr$::RawMessage, src: $pbr$::RawMessage);
           fn $repeated_len_thunk$(raw: $pbr$::RawRepeatedField) -> usize;
           fn $repeated_add_thunk$(raw: $pbr$::RawRepeatedField) -> $pbr$::RawMessage;
           fn $repeated_get_thunk$(raw: $pbr$::RawRepeatedField, index: usize) -> $pbr$::RawMessage;
@@ -304,6 +306,46 @@ void MessageGetMinitable(Context& ctx, const Descriptor& msg) {
   }
 }
 
+void MessageMergeFrom(Context& ctx, const Descriptor& msg) {
+  switch (ctx.opts().kernel) {
+    case Kernel::kCpp:
+      ctx.Emit(
+          {
+              {"merge_from_thunk", ThunkName(ctx, msg, "merge_from")},
+          },
+          R"rs(
+          pub fn merge_from<'src>(&mut self, src: impl $pb$::ViewProxy<'src, Proxied = $Msg$>) {
+            // SAFETY: self and src are both valid `$Msg$`s.
+            unsafe {
+              $merge_from_thunk$(self.raw_msg(), src.as_view().raw_msg());
+            }
+          }
+        )rs");
+      return;
+    case Kernel::kUpb:
+      ctx.Emit(
+          {
+              {"minitable", UpbMinitableName(msg)},
+          },
+          R"rs(
+          pub fn merge_from<'src>(&mut self, src: impl $pb$::ViewProxy<'src, Proxied = $Msg$>) {
+            // SAFETY: self and src are both valid `$Msg$`s.
+            unsafe {
+              assert!(
+                $pbr$::upb_Message_MergeFrom(self.raw_msg(), 
+                  src.as_view().raw_msg(),
+                  $std$::ptr::addr_of!($minitable$),
+                  // Use a nullptr for the ExtensionRegistry.
+                  $std$::ptr::null(),
+                  self.arena().raw())
+              );
+            }
+          }
+        )rs");
+      return;
+  }
+}
+
 void MessageProxiedInRepeated(Context& ctx, const Descriptor& msg) {
   switch (ctx.opts().kernel) {
     case Kernel::kCpp:
@@ -863,6 +905,7 @@ void GenerateRs(Context& ctx, const Descriptor& msg) {
         }},
        {"into_proxied_impl", [&] { IntoProxiedForMessage(ctx, msg); }},
        {"get_upb_minitable", [&] { MessageGetMinitable(ctx, msg); }},
+       {"msg_merge_from", [&] { MessageMergeFrom(ctx, msg); }},
        {"repeated_impl", [&] { MessageProxiedInRepeated(ctx, msg); }},
        {"map_value_impl", [&] { MessageProxiedInMapValue(ctx, msg); }},
        {"unwrap_upb",
@@ -1023,6 +1066,8 @@ void GenerateRs(Context& ctx, const Descriptor& msg) {
             $pb$::ViewProxy::as_view(self).to_owned()
           }
 
+          $msg_merge_from$
+
           $get_upb_minitable$
 
           $raw_arena_getter_for_msgmut$
@@ -1092,6 +1137,10 @@ void GenerateRs(Context& ctx, const Descriptor& msg) {
             $Msg$Mut::new($pbi$::Private, &mut self.inner)
           }
 
+          pub fn merge_from<'src>(&mut self, src: impl $pb$::ViewProxy<'src, Proxied = $Msg$>) {
+            self.as_mut().merge_from(src);
+          }
+
           $get_upb_minitable$
 
           $accessor_fns$
@@ -1181,6 +1230,7 @@ void GenerateThunksCc(Context& ctx, const Descriptor& msg) {
        {"serialize_thunk", ThunkName(ctx, msg, "serialize")},
        {"parse_thunk", ThunkName(ctx, msg, "parse")},
        {"copy_from_thunk", ThunkName(ctx, msg, "copy_from")},
+       {"merge_from_thunk", ThunkName(ctx, msg, "merge_from")},
        {"repeated_len_thunk", ThunkName(ctx, msg, "repeated_len")},
        {"repeated_get_thunk", ThunkName(ctx, msg, "repeated_get")},
        {"repeated_get_mut_thunk", ThunkName(ctx, msg, "repeated_get_mut")},
@@ -1229,6 +1279,10 @@ void GenerateThunksCc(Context& ctx, const Descriptor& msg) {
           dst->CopyFrom(*src);
         }
 
+        void $merge_from_thunk$($QualifiedMsg$* dst, const $QualifiedMsg$* src) {
+          dst->MergeFrom(*src);
+        }
+
         size_t $repeated_len_thunk$(google::protobuf::RepeatedPtrField<$QualifiedMsg$>* field) {
           return field->size();
         }