Add kotlin deprecation to messageOrNull extension properties in the generated code when the corresponding message is deprecated.

Additionally adds tests to ensure deprecated fields are properly annotated as such.

Fixes https://github.com/protocolbuffers/protobuf/issues/17084.

PiperOrigin-RevId: 653731276

java/kotlin/BUILD.bazel

@@ -276,6 +276,7 @@ kt_jvm_library(
         "//java/core:test_util",
         "@maven//:com_google_truth_truth",
         "@maven//:junit_junit",
+        "@rules_kotlin//kotlin/compiler:kotlin-reflect",
     ],
 )
 

java/kotlin/src/test/kotlin/com/google/protobuf/Proto2Test.kt

@@ -26,12 +26,14 @@ import protobuf_unittest.UnittestProto.TestAllTypes.NestedEnum
 import protobuf_unittest.UnittestProto.TestEmptyMessage
 import protobuf_unittest.UnittestProto.TestEmptyMessageWithExtensions
 import protobuf_unittest.copy
+import protobuf_unittest.deprecatedMessageOrNull
 import protobuf_unittest.foreignMessage
 import protobuf_unittest.optionalGroupExtension
 import protobuf_unittest.optionalNestedMessageOrNull
 import protobuf_unittest.repeatedGroupExtension
 import protobuf_unittest.testAllExtensions
 import protobuf_unittest.testAllTypes
+import protobuf_unittest.testDeprecatedFields
 import protobuf_unittest.testEmptyMessage
 import protobuf_unittest.testEmptyMessageWithExtensions
 import protobuf_unittest.testEnumMap
@@ -959,4 +961,15 @@ class Proto2Test {
     assertThat(someNestedMessage.optionalNestedMessageOrNull)
       .isEqualTo(TestAllTypesKt.nestedMessage { bb = 118 })
   }
+
+  @Test
+  fun testDeprecated() {
+    val testInstance =
+      protobuf_unittest.UnittestProto.TestDeprecatedFields.getDefaultInstance()
+    assertThat(testInstance::deprecatedMessageOrNull.annotations.any { it is Deprecated }).isTrue()
+
+    val unused = testDeprecatedFields {
+      assertThat(::deprecatedMessage.annotations.any { it is Deprecated }).isTrue()
+    }
+  }
 }

src/google/protobuf/compiler/java/full/message.cc

@@ -1330,6 +1330,11 @@ void ImmutableMessageGenerator::GenerateKotlinOrNull(
   for (int i = 0; i < descriptor_->field_count(); i++) {
     const FieldDescriptor* field = descriptor_->field(i);
     if (field->has_presence() && GetJavaType(field) == JAVATYPE_MESSAGE) {
+      if (field->options().deprecated()) {
+        printer->Print(
+            "@kotlin.Deprecated(message = \"Field $name$ is deprecated\")\n",
+            "name", context_->GetFieldGeneratorInfo(field)->name);
+      }
       printer->Print(
           "public val $full_classname$OrBuilder.$camelcase_name$OrNull: "
           "$full_name$?\n"

src/google/protobuf/compiler/java/full/message_field.cc

@@ -409,6 +409,7 @@ void ImmutableMessageFieldGenerator::GenerateKotlinOrNull(io::Printer* printer)
   if (descriptor_->has_presence() &&
       descriptor_->real_containing_oneof() == nullptr) {
     printer->Print(variables_,
+                   "$kt_deprecation$\n"
                    "public val $classname$Kt.Dsl.$name$OrNull: $kt_type$?\n"
                    "  get() = $kt_dsl_builder$.$name$OrNull\n");
   }

src/google/protobuf/compiler/java/lite/message.cc

@@ -854,6 +854,11 @@ void ImmutableMessageLiteGenerator::GenerateKotlinOrNull(
   for (int i = 0; i < descriptor_->field_count(); i++) {
     const FieldDescriptor* field = descriptor_->field(i);
     if (field->has_presence() && GetJavaType(field) == JAVATYPE_MESSAGE) {
+      if (field->options().deprecated()) {
+        printer->Print(
+            "@kotlin.Deprecated(message = \"Field $name$ is deprecated\")\n",
+            "name", context_->GetFieldGeneratorInfo(field)->name);
+      }
       printer->Print(
           "public val $full_classname$OrBuilder.$camelcase_name$OrNull: "
           "$full_name$?\n"

src/google/protobuf/compiler/java/lite/message_field.cc

@@ -309,10 +309,12 @@ void ImmutableMessageFieldLiteGenerator::GenerateKotlinDslMembers(
   GenerateKotlinOrNull(printer);
 }
 
-void ImmutableMessageFieldLiteGenerator::GenerateKotlinOrNull(io::Printer* printer) const {
+void ImmutableMessageFieldLiteGenerator::GenerateKotlinOrNull(
+    io::Printer* printer) const {
   if (descriptor_->has_presence() &&
       descriptor_->real_containing_oneof() == nullptr) {
     printer->Print(variables_,
+                   "$kt_deprecation$\n"
                    "public val $classname$Kt.Dsl.$name$OrNull: $kt_type$?\n"
                    "  get() = $kt_dsl_builder$.$name$OrNull\n");
   }