Add missing map thunks for nested enums.

While at it, remove the code for emitting map thunks for bytes map keys - bytes are not supported map keys.

PiperOrigin-RevId: 621806332

rust/test/enums.proto

@@ -59,3 +59,14 @@ enum TestEnumValueNameSameAsEnum {
   TEST_ENUM_VALUE_NAME_SAME_AS_ENUM_UNKNOWN = 0;
   TEST_ENUM_VALUE_NAME_SAME_AS_ENUM = 1;
 }
+
+// Regression test for maps with nested enum as value.
+message TestMapWithNestedEnum {
+  message InnerNested {
+    enum NestedEnum {
+      UNKNOWN = 0;
+      FOO = 1;
+    }
+  }
+  map<string, InnerNested.NestedEnum> string_map = 1;
+}

rust/test/shared/BUILD

@@ -337,6 +337,7 @@ rust_test(
         "@crate_index//:paste",
     ],
     deps = [
+        "//rust/test:enums_cc_rust_proto",
         "//rust/test:map_unittest_cc_rust_proto",
         "//rust/test:unittest_cc_rust_proto",
         "@crate_index//:googletest",
@@ -350,6 +351,7 @@ rust_test(
         "@crate_index//:paste",
     ],
     deps = [
+        "//rust/test:enums_upb_rust_proto",
         "//rust/test:map_unittest_upb_rust_proto",
         "//rust/test:unittest_upb_rust_proto",
         "@crate_index//:googletest",

rust/test/shared/accessors_map_test.rs

@@ -5,6 +5,7 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
+use enums_proto::{test_map_with_nested_enum, TestMapWithNestedEnum};
 use googletest::prelude::*;
 use map_unittest_proto::{MapEnum, TestMap, TestMapWithMessages};
 use paste::paste;
@@ -125,6 +126,14 @@ fn test_string_maps() {
     assert_that!(msg.map_string_string().len(), eq(0));
 }
 
+#[test]
+fn test_nested_enum_maps() {
+    // Verify that C++ thunks are generated and are with the right name for strings
+    TestMapWithNestedEnum::new()
+        .string_map_mut()
+        .insert("foo", test_map_with_nested_enum::inner_nested::NestedEnum::Foo);
+}
+
 #[test]
 fn test_bytes_and_string_copied() {
     let mut msg = TestMap::new();

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

@@ -1164,6 +1164,9 @@ void GenerateThunksCc(Context& ctx, const Descriptor& msg) {
           for (int i = 0; i < msg.nested_type_count(); ++i) {
             GenerateThunksCc(ctx, *msg.nested_type(i));
           }
+          for (int i = 0; i < msg.enum_type_count(); ++i) {
+            GenerateEnumThunksCc(ctx, *msg.enum_type(i));
+          }
         }},
        {"accessor_thunks",
         [&] {

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

@@ -419,7 +419,7 @@ PROTOBUF_CONSTINIT const MapKeyType kMapKeyTypes[] = {
      /*cc_key_t=*/"bool", /*cc_ffi_key_t=*/"bool",
      /*cc_from_ffi_key_expr=*/"key",
      /*cc_to_ffi_key_expr=*/"cpp_key"},
-    {/*thunk_ident=*/"string",
+    {/*thunk_ident=*/"ProtoStr",
      /*rs_key_t=*/"$pb$::ProtoStr",
      /*rs_ffi_key_t=*/"$pbi$::PtrAndLen",
      /*rs_to_ffi_key_expr=*/"key.as_bytes().into()",
@@ -429,16 +429,6 @@ PROTOBUF_CONSTINIT const MapKeyType kMapKeyTypes[] = {
      /*cc_ffi_key_t=*/"google::protobuf::rust_internal::PtrAndLen",
      /*cc_from_ffi_key_expr=*/
      "std::string(key.ptr, key.len)", /*cc_to_ffi_key_expr=*/
-     "google::protobuf::rust_internal::PtrAndLen(cpp_key.data(), cpp_key.size())"},
-    {/*thunk_ident=*/"bytes",
-     /*rs_key_t=*/"[u8]",
-     /*rs_ffi_key_t=*/"$pbi$::PtrAndLen",
-     /*rs_to_ffi_key_expr=*/"key.into()",
-     /*rs_from_ffi_key_expr=*/"ffi_key.as_ref()",
-     /*cc_key_t=*/"std::string",
-     /*cc_ffi_key_t=*/"google::protobuf::rust_internal::PtrAndLen",
-     /*cc_from_ffi_key_expr=*/
-     "std::string(key.ptr, key.len)", /*cc_to_ffi_key_expr=*/
      "google::protobuf::rust_internal::PtrAndLen(cpp_key.data(), cpp_key.size())"}};
 
 }  // namespace rust

src/google/protobuf/compiler/rust/naming.h

@@ -151,7 +151,7 @@ struct MapKeyType {
   absl::string_view cc_to_ffi_key_expr;
 };
 
-extern const MapKeyType kMapKeyTypes[7];
+extern const MapKeyType kMapKeyTypes[6];
 
 }  // namespace rust
 }  // namespace compiler