Fix has_presence to account for proto3 extensions in Java.

PiperOrigin-RevId: 613373080

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

@@ -1454,6 +1454,7 @@ public final class Descriptors {
       return isProto3Optional
           || getType() == Type.MESSAGE
           || getType() == Type.GROUP
+          || isExtension()
           || getContainingOneof() != null
           || this.features.getFieldPresence() != DescriptorProtos.FeatureSet.FieldPresence.IMPLICIT;
     }

java/core/src/test/java/com/google/protobuf/DescriptorsTest.java

@@ -54,6 +54,7 @@ import protobuf_unittest.UnittestProto.TestReservedFields;
 import protobuf_unittest.UnittestProto.TestService;
 import protobuf_unittest.UnittestRetention;
 import proto3_unittest.UnittestProto3;
+import protobuf_unittest.UnittestProto3Extensions.Proto3FileExtensions;
 import java.util.Collections;
 import java.util.List;
 import org.junit.Before;
@@ -1201,6 +1202,25 @@ public class DescriptorsTest {
       assertThat(features.getExtension(JavaFeaturesProto.java).getUtf8Validation())
           .isEqualTo(JavaFeaturesProto.JavaFeatures.Utf8Validation.DEFAULT);
     }
+
+    @Test
+    public void testProto3ExtensionPresence() {
+      FileDescriptorProto.Builder file = FileDescriptorProto.newBuilder();
+
+      assertThat(file.getOptions().hasExtension(Proto3FileExtensions.singularInt)).isFalse();
+      assertThat(file.getOptions().getExtension(Proto3FileExtensions.singularInt)).isEqualTo(0);
+
+      file.getOptionsBuilder().setExtension(Proto3FileExtensions.singularInt, 1);
+
+      assertThat(file.getOptions().hasExtension(Proto3FileExtensions.singularInt)).isTrue();
+      assertThat(file.getOptions().getExtension(Proto3FileExtensions.singularInt)).isEqualTo(1);
+    }
+
+    @Test
+    public void testProto3ExtensionHasPresence() {
+      assertThat(Proto3FileExtensions.singularInt.getDescriptor().hasPresence()).isTrue();
+      assertThat(Proto3FileExtensions.repeatedInt.getDescriptor().hasPresence()).isFalse();
+    }
   }
 
   public static class FeatureInheritanceTest {

src/google/protobuf/unittest_proto3_extensions.proto

@@ -4,6 +4,8 @@ package protobuf_unittest;
 
 import "google/protobuf/descriptor.proto";
 
+option java_outer_classname = "UnittestProto3Extensions";
+
 // For testing proto3 extension behaviors.
 message Proto3FileExtensions {
   extend google.protobuf.FileOptions {