Fix mutability bug in Java proto lite: sub-messages inside of oneofs were not

being set as immutable. This would allow code to get a builder for a
sub-message and modify the original (supposedly immutable) copy.

PiperOrigin-RevId: 511598810

java/core/src/main/java/com/google/protobuf/MessageSchema.java

@@ -5510,6 +5510,12 @@ final class MessageSchema<T> implements Schema<T> {
             getMessageFieldSchema(pos).makeImmutable(UNSAFE.getObject(message, offset));
           }
           break;
+        case 60: // ONEOF_MESSAGE
+        case 68: // ONEOF_GROUP
+          if (isOneofPresent(message, numberAt(pos), pos)) {
+            getMessageFieldSchema(pos).makeImmutable(UNSAFE.getObject(message, offset));
+          }
+          break;
         case 18: // DOUBLE_LIST:
         case 19: // FLOAT_LIST:
         case 20: // INT64_LIST:

java/lite/src/test/java/com/google/protobuf/LiteTest.java

@@ -190,6 +190,18 @@ public class LiteTest {
     }
   }
 
+  @Test
+  public void testParsedOneofSubMessageIsImmutable() throws InvalidProtocolBufferException {
+    TestAllTypesLite message =
+        TestAllTypesLite.parseFrom(
+            TestAllTypesLite.newBuilder()
+                .setOneofNestedMessage(NestedMessage.newBuilder().addDd(1234).build())
+                .build()
+                .toByteArray());
+    IntArrayList subList = (IntArrayList) message.getOneofNestedMessage().getDdList();
+    assertThat(subList.isModifiable()).isFalse();
+  }
+
   @Test
   public void testMemoization() throws Exception {
     GeneratedMessageLite<?, ?> message = TestUtilLite.getAllLiteExtensionsSet();
@@ -2365,8 +2377,7 @@ public class LiteTest {
     Foo fooWithOnlyValue = Foo.newBuilder().setValue(1).build();
 
     Foo fooWithValueAndExtension =
-        fooWithOnlyValue
-            .toBuilder()
+        fooWithOnlyValue.toBuilder()
             .setValue(1)
             .setExtension(Bar.fooExt, Bar.newBuilder().setName("name").build())
             .build();
@@ -2382,8 +2393,7 @@ public class LiteTest {
     Foo fooWithOnlyValue = Foo.newBuilder().setValue(1).build();
 
     Foo fooWithValueAndExtension =
-        fooWithOnlyValue
-            .toBuilder()
+        fooWithOnlyValue.toBuilder()
             .setValue(1)
             .setExtension(Bar.fooExt, Bar.newBuilder().setName("name").build())
             .build();

src/google/protobuf/unittest_lite.proto

@@ -47,6 +47,7 @@ message TestAllTypesLite {
   message NestedMessage {
     optional int32 bb = 1;
     optional int64 cc = 2;
+    repeated int32 dd = 3 [packed = true];
   }
 
   message NestedMessage2 {