Enable editions support for Java Lite.

java_features.proto and descriptor.proto should now both be included in the Java Lite and Kotlin Lite maven releases.

Fixes https://github.com/protocolbuffers/protobuf/issues/7331

PiperOrigin-RevId: 618251348

conformance/BUILD.bazel

@@ -271,6 +271,8 @@ java_binary(
         "//:protobuf_javalite",
         "//:test_messages_proto2_java_proto_lite",
         "//:test_messages_proto3_java_proto_lite",
+        "//src/google/protobuf/editions:test_messages_proto2_editions_java_proto_lite",
+        "//src/google/protobuf/editions:test_messages_proto3_editions_java_proto_lite",
     ],
 )
 

conformance/ConformanceJavaLite.java

@@ -5,6 +5,7 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
+import com.google.protobuf.AbstractMessageLite;
 import com.google.protobuf.ByteString;
 import com.google.protobuf.CodedInputStream;
 import com.google.protobuf.ExtensionRegistryLite;
@@ -15,6 +16,8 @@ import com.google.protobuf.conformance.Conformance;
 import com.google.protobuf_test_messages.proto2.TestMessagesProto2;
 import com.google.protobuf_test_messages.proto2.TestMessagesProto2.TestAllTypesProto2;
 import com.google.protobuf_test_messages.proto3.TestMessagesProto3;
+import com.google.protobuf_test_messages.editions.proto2.TestMessagesProto2Editions;
+import com.google.protobuf_test_messages.editions.proto3.TestMessagesProto3Editions;
 import com.google.protobuf_test_messages.proto3.TestMessagesProto3.TestAllTypesProto3;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
@@ -203,42 +206,62 @@ class ConformanceJavaLite {
     return messages.get(0);
   }
 
+  private Class<? extends AbstractMessageLite> createTestMessage(String messageType) {
+    switch (messageType) {
+      case "protobuf_test_messages.proto3.TestAllTypesProto3":
+        return TestAllTypesProto3.class;
+      case "protobuf_test_messages.proto2.TestAllTypesProto2":
+        return TestAllTypesProto2.class;
+      case "protobuf_test_messages.editions.proto3.TestAllTypesProto3":
+        return TestMessagesProto3Editions.TestAllTypesProto3.class;
+      case "protobuf_test_messages.editions.proto2.TestAllTypesProto2":
+        return TestMessagesProto2Editions.TestAllTypesProto2.class;
+      default:
+        throw new IllegalArgumentException(
+            "Protobuf request has unexpected payload type: " + messageType);
+    }
+  }
+
+  private Class<?> createTestFile(String messageType) {
+    switch (messageType) {
+      case "protobuf_test_messages.proto3.TestAllTypesProto3":
+        return TestMessagesProto3.class;
+      case "protobuf_test_messages.proto2.TestAllTypesProto2":
+        return TestMessagesProto2.class;
+      case "protobuf_test_messages.editions.proto3.TestAllTypesProto3":
+        return TestMessagesProto3Editions.class;
+      case "protobuf_test_messages.editions.proto2.TestAllTypesProto2":
+        return TestMessagesProto2Editions.class;
+      default:
+        throw new IllegalArgumentException(
+            "Protobuf request has unexpected payload type: " + messageType);
+    }
+  }
+
+  @SuppressWarnings("unchecked")
   private Conformance.ConformanceResponse doTest(Conformance.ConformanceRequest request) {
     com.google.protobuf.MessageLite testMessage;
-    boolean isProto3 =
-        request.getMessageType().equals("protobuf_test_messages.proto3.TestAllTypesProto3");
-    boolean isProto2 =
-        request.getMessageType().equals("protobuf_test_messages.proto2.TestAllTypesProto2");
-
+    String messageType = request.getMessageType();
     switch (request.getPayloadCase()) {
       case PROTOBUF_PAYLOAD:
         {
-          if (isProto3) {
-            try {
-              ExtensionRegistryLite extensions = ExtensionRegistryLite.newInstance();
-              TestMessagesProto3.registerAllExtensions(extensions);
-              testMessage =
-                  parseBinary(
-                      request.getProtobufPayload(), TestAllTypesProto3.parser(), extensions);
-            } catch (InvalidProtocolBufferException e) {
-              return Conformance.ConformanceResponse.newBuilder()
-                  .setParseError(e.getMessage())
-                  .build();
-            }
-          } else if (isProto2) {
-            try {
-              ExtensionRegistryLite extensions = ExtensionRegistryLite.newInstance();
-              TestMessagesProto2.registerAllExtensions(extensions);
-              testMessage =
-                  parseBinary(
-                      request.getProtobufPayload(), TestAllTypesProto2.parser(), extensions);
-            } catch (InvalidProtocolBufferException e) {
-              return Conformance.ConformanceResponse.newBuilder()
-                  .setParseError(e.getMessage())
-                  .build();
-            }
-          } else {
-            throw new RuntimeException("Protobuf request doesn't have specific payload type.");
+          try {
+            ExtensionRegistryLite extensions = ExtensionRegistryLite.newInstance();
+            createTestFile(messageType)
+                .getMethod("registerAllExtensions", ExtensionRegistryLite.class)
+                .invoke(null, extensions);
+            testMessage =
+                parseBinary(
+                    request.getProtobufPayload(),
+                    (Parser<AbstractMessageLite>)
+                        createTestMessage(messageType).getMethod("parser").invoke(null),
+                    extensions);
+          } catch (InvalidProtocolBufferException e) {
+            return Conformance.ConformanceResponse.newBuilder()
+                .setParseError(e.getMessage())
+                .build();
+          } catch (Exception e) {
+            throw new RuntimeException(e);
           }
           break;
         }

conformance/failure_list_java_lite.txt

@@ -8,3 +8,7 @@ Required.Proto3.ProtobufInput.PrematureEofInDelimitedDataForKnownNonRepeatedValu
 Required.Proto3.ProtobufInput.PrematureEofInDelimitedDataForKnownRepeatedValue.MESSAGE
 Required.Proto2.ProtobufInput.PrematureEofInDelimitedDataForKnownNonRepeatedValue.MESSAGE
 Required.Proto2.ProtobufInput.PrematureEofInDelimitedDataForKnownRepeatedValue.MESSAGE
+Required.Editions_Proto3.ProtobufInput.PrematureEofInDelimitedDataForKnownNonRepeatedValue.MESSAGE
+Required.Editions_Proto3.ProtobufInput.PrematureEofInDelimitedDataForKnownRepeatedValue.MESSAGE
+Required.Editions_Proto2.ProtobufInput.PrematureEofInDelimitedDataForKnownNonRepeatedValue.MESSAGE
+Required.Editions_Proto2.ProtobufInput.PrematureEofInDelimitedDataForKnownRepeatedValue.MESSAGE

java/core/BUILD.bazel

@@ -109,8 +109,10 @@ internal_gen_well_known_protos_java(
     name = "gen_well_known_protos_javalite",
     javalite = True,
     deps = [
+        ":java_features_proto",
         "//:any_proto",
         "//:api_proto",
+        "//:descriptor_proto",
         "//:duration_proto",
         "//:empty_proto",
         "//:field_mask_proto",
@@ -155,7 +157,9 @@ protobuf_java_export(
     maven_coordinates = "com.google.protobuf:protobuf-javalite:%s" % PROTOBUF_JAVA_VERSION,
     pom_template = "//java/lite:pom_template.xml",
     resources = [
+        ":java_features_proto",
         "//:lite_well_known_protos",
+        "//src/google/protobuf:descriptor_proto_srcs",
     ],
     tags = ["manual"],
     runtime_deps = [":lite_bundle"],
@@ -170,7 +174,11 @@ proto_library(
     name = "java_features_proto",
     srcs = ["src/main/java/com/google/protobuf/java_features.proto"],
     strip_import_prefix = "/java/core/src/main/java/com",
-    visibility = ["//pkg:__pkg__"],
+    visibility = [
+        "//java/kotlin-lite:__pkg__",
+        "//java/lite:__pkg__",
+        "//pkg:__pkg__",
+    ],
     deps = ["//:descriptor_proto"],
 )
 

java/core/src/test/proto/com/google/protobuf/any_test.proto

@@ -5,7 +5,7 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-syntax = "proto3";
+edition = "2023";
 
 package any_test;
 

java/core/src/test/proto/com/google/protobuf/cached_field_size_test.proto

@@ -6,7 +6,7 @@
 // https://developers.google.com/open-source/licenses/bsd
 
 // A regression test for b/74087933
-syntax = "proto2";
+edition = "2023";
 
 package protobuf_unittest;
 
@@ -17,6 +17,6 @@ option optimize_for = CODE_SIZE;
 option java_multiple_files = true;
 
 message TestCachedFieldSizeMessage {
-  optional protobuf_unittest.TestPackedTypes proto2_child = 1;
-  optional proto3_unittest.TestPackedTypes proto3_child = 2;
+  protobuf_unittest.TestPackedTypes proto2_child = 1;
+  proto3_unittest.TestPackedTypes proto3_child = 2;
 }

java/core/src/test/proto/com/google/protobuf/dynamic_message_test.proto

@@ -5,10 +5,11 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-syntax = "proto2";
+edition = "2023";
 
 package dynamic_message_test;
 
+option features.utf8_validation = NONE;
 option java_package = "dynamicmessagetest";
 option java_outer_classname = "DynamicMessageTestProto";
 

java/core/src/test/proto/com/google/protobuf/field_presence_test.proto

@@ -5,12 +5,13 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-syntax = "proto3";
+edition = "2023";
 
 package field_presence_test;
 
 import "google/protobuf/unittest.proto";
 
+option features.field_presence = IMPLICIT;
 option java_package = "com.google.protobuf";
 option java_outer_classname = "FieldPresenceTestProto";
 
@@ -20,6 +21,7 @@ message TestAllTypes {
     BAR = 1;
     BAZ = 2;
   }
+
   message NestedMessage {
     int32 value = 1;
   }
@@ -48,7 +50,7 @@ message TestAllTypes {
   repeated NestedEnum repeated_nested_enum = 24;
   repeated NestedMessage repeated_nested_message = 25;
   repeated protobuf_unittest.TestRequired repeated_proto2_message = 26;
-  repeated NestedEnum packed_nested_enum = 27 [packed = true];
+  repeated NestedEnum packed_nested_enum = 27;
 }
 
 message TestOptionalFieldsOnly {

java/core/src/test/proto/com/google/protobuf/lazy_fields_lite.proto

@@ -9,15 +9,19 @@
 //
 // A proto file with lazy fields
 
-syntax = "proto2";
+edition = "2023";
 
 package protobuf_unittest;
 
+option features.utf8_validation = NONE;
+
 message LazyMessageLite {
-  optional int32 num = 1;
-  optional int32 num_with_default = 2 [default = 421];
-  optional LazyInnerMessageLite inner = 3 [lazy = true];
-  repeated LazyInnerMessageLite repeated_inner = 4 ;
+  int32 num = 1;
+  int32 num_with_default = 2 [default = 421];
+
+  LazyInnerMessageLite inner = 3 [lazy = true];
+
+  repeated LazyInnerMessageLite repeated_inner = 4;
 
   oneof oneof_field {
     int32 oneof_num = 5;
@@ -26,21 +30,23 @@ message LazyMessageLite {
 }
 
 message LazyInnerMessageLite {
-  optional int32 num = 1;
-  optional int32 num_with_default = 2 [default = 42];
-  optional LazyNestedInnerMessageLite nested = 3 [lazy = true];
+  int32 num = 1;
+  int32 num_with_default = 2 [default = 42];
+
+  LazyNestedInnerMessageLite nested = 3 [lazy = true];
 
   extensions 1000 to max;
 }
 
 message LazyExtension {
   extend LazyInnerMessageLite {
-    optional LazyExtension extension = 1000;
+    LazyExtension extension = 1000;
   }
-  optional string name = 1;
+
+  string name = 1;
 }
 
 message LazyNestedInnerMessageLite {
-  optional int32 num = 1;
-  optional int32 num_with_default = 2 [default = 4];
+  int32 num = 1;
+  int32 num_with_default = 2 [default = 4];
 }

java/core/src/test/proto/com/google/protobuf/lite_equals_and_hash.proto

@@ -7,10 +7,11 @@
 
 // Author: pbogle@google.com (Phil Bogle)
 
-syntax = "proto2";
+edition = "2023";
 
 package protobuf_unittest.lite_equals_and_hash;
 
+option features.utf8_validation = NONE;
 
 message TestOneofEquals {
   oneof oneof_field {
@@ -20,15 +21,18 @@ message TestOneofEquals {
 }
 
 message Foo {
-  optional int32 value = 1;
+  int32 value = 1;
   repeated Bar bar = 2;
   map<string, string> my_map = 3;
+
   oneof Single {
     sint64 sint64 = 4;
-    // LINT: ALLOW_GROUPS
-    group MyGroup = 5 {
-      optional int32 value = 1;
-    }
+    MyGroup mygroup = 5 [features.message_encoding = DELIMITED];
+  }
+
+  // LINT: ALLOW_GROUPS
+  message MyGroup {
+    int32 value = 1;
   }
 
   extensions 100 to max;
@@ -36,25 +40,27 @@ message Foo {
 
 message Bar {
   extend Foo {
-    optional Bar foo_ext = 100;
+    Bar foo_ext = 100;
   }
 
-  optional string name = 1;
+  string name = 1;
 }
 
 message BarPrime {
-  optional string name = 1;
+  string name = 1;
 }
 
 message Empty {}
 
 extend Foo {
-  optional int32 varint = 101;
-  optional fixed32 fixed32 = 102;
-  optional fixed64 fixed64 = 103;
-  optional group MyGroup = 104 {
-    optional string group_value = 1;
-  }
+  int32 varint = 101;
+  fixed32 fixed32 = 102;
+  fixed64 fixed64 = 103;
+  MyGroup mygroup = 104 [features.message_encoding = DELIMITED];
+}
+
+message MyGroup {
+  string group_value = 1;
 }
 
 message TestRecursiveOneof {

java/core/src/test/proto/com/google/protobuf/map_for_proto2_lite_test.proto

@@ -5,18 +5,21 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-syntax = "proto2";
+edition = "2023";
 
 package map_for_proto2_lite_test;
 
+option features.enum_type = CLOSED;
+option features.utf8_validation = NONE;
 option java_outer_classname = "MapForProto2TestProto";
 option optimize_for = LITE_RUNTIME;
 option java_package = "map_lite_test";
 
 message TestMap {
   message MessageValue {
-    optional int32 value = 1;
+    int32 value = 1;
   }
+
   enum EnumValue {
     FOO = 0;
     BAR = 1;
@@ -32,8 +35,9 @@ message TestMap {
   map<string, int32> string_to_int32_field = 6;
 
   message MessageWithRequiredFields {
-    required int32 value = 1;
+    int32 value = 1 [features.field_presence = LEGACY_REQUIRED];
   }
+
   map<int32, MessageWithRequiredFields> required_message_map = 11;
 }
 
@@ -46,7 +50,7 @@ message TestUnknownEnumValue {
 // Test that the maps initialization code works correctly when the map field
 // references the containing message.
 message TestRecursiveMap {
-  optional int32 value = 1;
+  int32 value = 1;
   map<int32, TestRecursiveMap> recursive_map_field = 2;
 }
 
@@ -54,14 +58,19 @@ message TestRecursiveMap {
 message BizarroTestMap {
   // same key type, different value
   map<int32, bytes> int32_to_int32_field = 1;
+
   // different key and value types
   map<string, int32> int32_to_string_field = 2;
+
   // different key types, same value
   map<string, int32> int32_to_bytes_field = 3;
+
   // different key and value types
   map<string, bytes> int32_to_enum_field = 4;
+
   // different key and value types
   map<string, bytes> int32_to_message_field = 5;
+
   // same key type, different value
   map<string, bytes> string_to_int32_field = 6;
 }
@@ -77,11 +86,14 @@ message ReservedAsMapField {
   map<string, uint32> class = 4;
   map<string, uint32> int = 5;
   map<string, uint32> void = 6;
+
   // These are also proto keywords
   map<string, uint32> string = 7;
   map<string, uint32> package = 8;
+
   // Most recent Java reserved word
   map<string, uint32> enum = 9;
+
   // null is not a 'reserved word' per se but as a literal needs similar care
   map<string, uint32> null = 10;
 }
@@ -91,17 +103,21 @@ message ReservedAsMapFieldWithEnumValue {
     A = 0;
     B = 1;
   }
+
   map<string, SampleEnum> if = 1;
   map<string, SampleEnum> const = 2;
   map<string, SampleEnum> private = 3;
   map<string, SampleEnum> class = 4;
   map<string, SampleEnum> int = 5;
   map<string, SampleEnum> void = 6;
+
   // These are also proto keywords
   map<string, SampleEnum> string = 7;
   map<string, SampleEnum> package = 8;
+
   // Most recent Java reserved word
   map<string, SampleEnum> enum = 9;
+
   // null is not a 'reserved word' per se but as a literal needs similar care
   map<string, SampleEnum> null = 10;
 }

java/core/src/test/proto/com/google/protobuf/map_for_proto2_test.proto

@@ -5,17 +5,20 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-syntax = "proto2";
+edition = "2023";
 
 package map_for_proto2_test;
 
+option features.enum_type = CLOSED;
+option features.utf8_validation = NONE;
 option java_package = "map_test";
 option java_outer_classname = "MapForProto2TestProto";
 
 message TestMap {
   message MessageValue {
-    optional int32 value = 1;
+    int32 value = 1;
   }
+
   enum EnumValue {
     FOO = 0;
     BAR = 1;
@@ -31,8 +34,9 @@ message TestMap {
   map<string, int32> string_to_int32_field = 6;
 
   message MessageWithRequiredFields {
-    required int32 value = 1;
+    int32 value = 1 [features.field_presence = LEGACY_REQUIRED];
   }
+
   map<int32, MessageWithRequiredFields> required_message_map = 11;
 }
 
@@ -45,7 +49,7 @@ message TestUnknownEnumValue {
 // Test that the maps initialization code works correctly when the map field
 // references the containing message.
 message TestRecursiveMap {
-  optional int32 value = 1;
+  int32 value = 1;
   map<int32, TestRecursiveMap> recursive_map_field = 2;
 }
 
@@ -53,14 +57,19 @@ message TestRecursiveMap {
 message BizarroTestMap {
   // same key type, different value
   map<int32, bytes> int32_to_int32_field = 1;
+
   // different key and value types
   map<string, int32> int32_to_string_field = 2;
+
   // different key types, same value
   map<string, int32> int32_to_bytes_field = 3;
+
   // different key and value types
   map<string, bytes> int32_to_enum_field = 4;
+
   // different key and value types
   map<string, bytes> int32_to_message_field = 5;
+
   // same key type, different value
   map<string, bytes> string_to_int32_field = 6;
 }
@@ -76,11 +85,14 @@ message ReservedAsMapField {
   map<string, uint32> class = 4;
   map<string, uint32> int = 5;
   map<string, uint32> void = 6;
+
   // These are also proto keywords
   map<string, uint32> string = 7;
   map<string, uint32> package = 8;
+
   // Most recent Java reserved word
   map<string, uint32> enum = 9;
+
   // null is not a 'reserved word' per se but as a literal needs similar care
   map<string, uint32> null = 10;
 }
@@ -90,17 +102,21 @@ message ReservedAsMapFieldWithEnumValue {
     A = 0;
     B = 1;
   }
+
   map<string, SampleEnum> if = 1;
   map<string, SampleEnum> const = 2;
   map<string, SampleEnum> private = 3;
   map<string, SampleEnum> class = 4;
   map<string, SampleEnum> int = 5;
   map<string, SampleEnum> void = 6;
+
   // These are also proto keywords
   map<string, SampleEnum> string = 7;
   map<string, SampleEnum> package = 8;
+
   // Most recent Java reserved word
   map<string, SampleEnum> enum = 9;
+
   // null is not a 'reserved word' per se but as a literal needs similar care
   map<string, SampleEnum> null = 10;
 }

java/core/src/test/proto/com/google/protobuf/map_initialization_order_test.proto

@@ -14,10 +14,11 @@
 //        a. getDescriptor() is called on another message in the same file.
 //        b. use protobuf reflection to access the map field.
 // The symptom is a NullPointerException being thrown.
-syntax = "proto2";
+edition = "2023";
 
 package map_test;
 
+option features.utf8_validation = NONE;
 option java_package = "map_test";
 option java_outer_classname = "MapInitializationOrderTest";
 option java_multiple_files = true;
@@ -27,11 +28,12 @@ option java_multiple_files = true;
 
 message Message1 {
   map<string, bool> map_field = 1;
+
   extensions 1000 to max;
 }
 
 extend Message1 {
-  optional Message1 recursive_extension = 1001;
+  Message1 recursive_extension = 1001;
 }
 
 message RedactAllTypes {}

java/core/src/test/proto/com/google/protobuf/map_lite_test.proto

@@ -5,10 +5,12 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-syntax = "proto3";
+edition = "2023";
 
 package map_lite_test;
 
+option features.field_presence = IMPLICIT;
+
 option optimize_for = LITE_RUNTIME;
 option java_package = "map_lite_test";
 option java_outer_classname = "MapTestProto";
@@ -17,6 +19,7 @@ message TestMap {
   message MessageValue {
     int32 value = 1;
   }
+
   enum EnumValue {
     FOO = 0;
     BAR = 1;
@@ -45,14 +48,19 @@ message TestOnChangeEventPropagation {
 message BizarroTestMap {
   // same key type, different value
   map<int32, bytes> int32_to_int32_field = 1;
+
   // different key and value types
   map<string, int32> int32_to_string_field = 2;
+
   // different key types, same value
   map<string, int32> int32_to_bytes_field = 3;
+
   // different key and value types
   map<string, bytes> int32_to_enum_field = 4;
+
   // different key and value types
   map<string, bytes> int32_to_message_field = 5;
+
   // same key type, different value
   map<string, bytes> string_to_int32_field = 6;
 }
@@ -68,11 +76,14 @@ message ReservedAsMapField {
   map<string, uint32> class = 4;
   map<string, uint32> int = 5;
   map<string, uint32> void = 6;
+
   // These are also proto keywords
   map<string, uint32> string = 7;
   map<string, uint32> package = 8;
+
   // Most recent Java reserved word
   map<string, uint32> enum = 9;
+
   // null is not a 'reserved word' per se but as a literal needs similar care
   map<string, uint32> null = 10;
 }
@@ -82,22 +93,26 @@ message ReservedAsMapFieldWithEnumValue {
     A = 0;
     B = 1;
   }
+
   map<string, SampleEnum> if = 1;
   map<string, SampleEnum> const = 2;
   map<string, SampleEnum> private = 3;
   map<string, SampleEnum> class = 4;
   map<string, SampleEnum> int = 5;
   map<string, SampleEnum> void = 6;
+
   // These are also proto keywords
   map<string, SampleEnum> string = 7;
   map<string, SampleEnum> package = 8;
+
   // Most recent Java reserved word
   map<string, SampleEnum> enum = 9;
+
   // null is not a 'reserved word' per se but as a literal needs similar care
   map<string, SampleEnum> null = 10;
 }
 
 // https://github.com/protocolbuffers/protobuf/issues/9785
 message MapContainer {
-  map<string,string> my_map = 1;
+  map<string, string> my_map = 1;
 }

java/core/src/test/proto/com/google/protobuf/map_test.proto

@@ -5,10 +5,12 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-syntax = "proto3";
+edition = "2023";
 
 package map_test;
 
+option features.field_presence = IMPLICIT;
+
 option java_package = "map_test";
 option java_outer_classname = "MapTestProto";
 
@@ -16,6 +18,7 @@ message TestMap {
   message MessageValue {
     int32 value = 1;
   }
+
   enum EnumValue {
     FOO = 0;
     BAR = 1;
@@ -44,14 +47,19 @@ message TestOnChangeEventPropagation {
 message BizarroTestMap {
   // same key type, different value
   map<int32, bytes> int32_to_int32_field = 1;
+
   // different key and value types
   map<string, int32> int32_to_string_field = 2;
+
   // different key types, same value
   map<string, int32> int32_to_bytes_field = 3;
+
   // different key and value types
   map<string, bytes> int32_to_enum_field = 4;
+
   // different key and value types
   map<string, bytes> int32_to_message_field = 5;
+
   // same key type, different value
   map<string, bytes> string_to_int32_field = 6;
 }
@@ -67,11 +75,14 @@ message ReservedAsMapField {
   map<string, uint32> class = 4;
   map<string, uint32> int = 5;
   map<string, uint32> void = 6;
+
   // These are also proto keywords
   map<string, uint32> string = 7;
   map<string, uint32> package = 8;
+
   // Most recent Java reserved word
   map<string, uint32> enum = 9;
+
   // null is not a 'reserved word' per se but as a literal needs similar care
   map<string, uint32> null = 10;
 }
@@ -81,22 +92,26 @@ message ReservedAsMapFieldWithEnumValue {
     A = 0;
     B = 1;
   }
+
   map<string, SampleEnum> if = 1;
   map<string, SampleEnum> const = 2;
   map<string, SampleEnum> private = 3;
   map<string, SampleEnum> class = 4;
   map<string, SampleEnum> int = 5;
   map<string, SampleEnum> void = 6;
+
   // These are also proto keywords
   map<string, SampleEnum> string = 7;
   map<string, SampleEnum> package = 8;
+
   // Most recent Java reserved word
   map<string, SampleEnum> enum = 9;
+
   // null is not a 'reserved word' per se but as a literal needs similar care
   map<string, SampleEnum> null = 10;
 }
 
 // https://github.com/protocolbuffers/protobuf/issues/9785
 message MapContainer {
-  map<string,string> my_map = 1;
+  map<string, string> my_map = 1;
 }

java/core/src/test/proto/com/google/protobuf/multiple_files_test.proto

@@ -9,7 +9,7 @@
 //
 // A proto file which tests the java_multiple_files option.
 
-syntax = "proto2";
+edition = "2023";
 
 // Some generic_services option(s) added automatically.
 // See:  http://go/proto2-generic-services-default
@@ -18,29 +18,33 @@ package protobuf_unittest;
 import "google/protobuf/descriptor.proto";
 import "google/protobuf/unittest.proto";
 
+option features.enum_type = CLOSED;
 option java_generic_services = true;  // auto-added
 option java_multiple_files = true;
 option java_outer_classname = "MultipleFilesTestProto";
 
 message MessageWithNoOuter {
   message NestedMessage {
-    optional int32 i = 1;
+    int32 i = 1;
   }
+
   enum NestedEnum {
     BAZ = 3;
   }
-  optional NestedMessage nested = 1;
+
+  NestedMessage nested = 1;
   repeated TestAllTypes foreign = 2;
-  optional NestedEnum nested_enum = 3;
-  optional EnumWithNoOuter foreign_enum = 4;
+  NestedEnum nested_enum = 3;
+  EnumWithNoOuter foreign_enum = 4;
 }
 
 extend google.protobuf.EnumValueOptions {
-  optional int32 enum_value_option = 7654321;
+  int32 enum_value_option = 7654321;
 }
 
 enum EnumWithNoOuter {
   FOO = 1 [(enum_value_option) = 12345];
+
   BAR = 2;
 }
 
@@ -49,5 +53,5 @@ service ServiceWithNoOuter {
 }
 
 extend TestAllExtensions {
-  optional int32 extension_with_outer = 1234567;
+  int32 extension_with_outer = 1234567;
 }

java/core/src/test/proto/com/google/protobuf/nested_builders_test.proto

@@ -6,8 +6,7 @@
 // https://developers.google.com/open-source/licenses/bsd
 
 // Author: jonp@google.com (Jon Perlow)
-//
-syntax = "proto2";
+edition = "2023";
 
 package protobuf_unittest;
 
@@ -15,21 +14,21 @@ option java_multiple_files = true;
 option java_outer_classname = "NestedBuilders";
 
 message Vehicle {
-  optional Engine engine = 1;
+  Engine engine = 1;
   repeated Wheel wheel = 2;
 }
 
 message Engine {
-  optional int32 cylinder = 1;
-  optional int32 liters = 2;
-  optional TimingBelt timing_belt = 3;
+  int32 cylinder = 1;
+  int32 liters = 2;
+  TimingBelt timing_belt = 3;
 }
 
 message TimingBelt {
-  optional int32 number_of_teeth = 1;
+  int32 number_of_teeth = 1;
 }
 
 message Wheel {
-  optional int32 radius = 1;
-  optional int32 width = 2;
+  int32 radius = 1;
+  int32 width = 2;
 }

java/core/src/test/proto/com/google/protobuf/nested_extension.proto

@@ -10,7 +10,9 @@
 // A proto file with nested extensions. Note that this must be defined in
 // a separate file to properly test the initialization of the outer class.
 
-syntax = "proto2";
+// LINT: LEGACY_NAMES
+
+edition = "2023";
 
 package protobuf_unittest;
 
@@ -19,7 +21,7 @@ import "com/google/protobuf/non_nested_extension.proto";
 
 message MyNestedExtension {
   extend MessageToBeExtended {
-    optional MessageToBeExtended recursiveExtension = 2;
-    optional int32 default = 2002;
+    MessageToBeExtended recursiveExtension = 2;
+    int32 default = 2002;
   }
 }

java/core/src/test/proto/com/google/protobuf/nested_extension_lite.proto

@@ -11,7 +11,9 @@
 // this must be defined in a separate file to properly test the initialization
 // of the outer class.
 
-syntax = "proto2";
+// LINT: LEGACY_NAMES
+
+edition = "2023";
 
 package protobuf_unittest;
 
@@ -21,7 +23,7 @@ option optimize_for = LITE_RUNTIME;
 
 message MyNestedExtensionLite {
   extend MessageLiteToBeExtended {
-    optional MessageLiteToBeExtended recursiveExtensionLite = 3;
-    optional double private = 2004;
+    MessageLiteToBeExtended recursiveExtensionLite = 3;
+    double private = 2004;
   }
 }

java/core/src/test/proto/com/google/protobuf/non_nested_extension.proto

@@ -9,10 +9,13 @@
 //
 // A proto file with extensions.
 
-syntax = "proto2";
+// LINT: LEGACY_NAMES
+
+edition = "2023";
 
 package protobuf_unittest;
 
+option features.utf8_validation = NONE;
 
 message MessageToBeExtended {
   extensions 1 to max;
@@ -21,6 +24,6 @@ message MessageToBeExtended {
 message MyNonNestedExtension {}
 
 extend MessageToBeExtended {
-  optional MyNonNestedExtension nonNestedExtension = 1;
-  optional string if = 2000;
+  MyNonNestedExtension nonNestedExtension = 1;
+  string if = 2000;
 }

java/core/src/test/proto/com/google/protobuf/non_nested_extension_lite.proto

@@ -9,7 +9,9 @@
 //
 // A proto file with extensions for a MessageLite messages.
 
-syntax = "proto2";
+// LINT: LEGACY_NAMES
+
+edition = "2023";
 
 package protobuf_unittest;
 
@@ -22,6 +24,6 @@ message MessageLiteToBeExtended {
 message MyNonNestedExtensionLite {}
 
 extend MessageLiteToBeExtended {
-  optional MyNonNestedExtensionLite nonNestedExtensionLite = 1;
-  optional bool package = 2006;
+  MyNonNestedExtensionLite nonNestedExtensionLite = 1;
+  bool package = 2006;
 }

java/core/src/test/proto/com/google/protobuf/outer_class_name_test.proto

@@ -5,7 +5,7 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-syntax = "proto2";
+edition = "2023";
 
 package protobuf_unittest;
 

java/core/src/test/proto/com/google/protobuf/outer_class_name_test2.proto

@@ -5,7 +5,7 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-syntax = "proto2";
+edition = "2023";
 
 package protobuf_unittest;
 

java/core/src/test/proto/com/google/protobuf/outer_class_name_test3.proto

@@ -5,7 +5,7 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-syntax = "proto2";
+edition = "2023";
 
 package protobuf_unittest;
 
@@ -15,6 +15,10 @@ message TestMessage3 {
     // This enum's name is the same with the default outer class name of this
     // proto file. It's used to test if the compiler can avoid this conflict
     // correctly.
-    enum OuterClassNameTest3 { DUMMY_VALUE = 1; }
+    enum OuterClassNameTest3 {
+      option features.enum_type = CLOSED;
+
+      DUMMY_VALUE = 1;
+    }
   }
 }

java/core/src/test/proto/com/google/protobuf/packed_field_test.proto

@@ -5,7 +5,7 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-syntax = "proto3";
+edition = "2023";
 
 package packed_field_test;
 
@@ -36,18 +36,45 @@ message TestAllTypes {
 }
 
 message TestUnpackedTypes {
-  repeated int32 repeated_int32 = 1 [packed = false];
-  repeated int64 repeated_int64 = 2 [packed = false];
-  repeated uint32 repeated_uint32 = 3 [packed = false];
-  repeated uint64 repeated_uint64 = 4 [packed = false];
-  repeated sint32 repeated_sint32 = 5 [packed = false];
-  repeated sint64 repeated_sint64 = 6 [packed = false];
-  repeated fixed32 repeated_fixed32 = 7 [packed = false];
-  repeated fixed64 repeated_fixed64 = 8 [packed = false];
-  repeated sfixed32 repeated_sfixed32 = 9 [packed = false];
-  repeated sfixed64 repeated_sfixed64 = 10 [packed = false];
-  repeated float repeated_float = 11 [packed = false];
-  repeated double repeated_double = 12 [packed = false];
-  repeated bool repeated_bool = 13 [packed = false];
-  repeated TestAllTypes.NestedEnum repeated_nested_enum = 14 [packed = false];
+  repeated int32 repeated_int32 = 1
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated int64 repeated_int64 = 2
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated uint32 repeated_uint32 = 3
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated uint64 repeated_uint64 = 4
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sint32 repeated_sint32 = 5
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sint64 repeated_sint64 = 6
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated fixed32 repeated_fixed32 = 7
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated fixed64 repeated_fixed64 = 8
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sfixed32 repeated_sfixed32 = 9
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sfixed64 repeated_sfixed64 = 10
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated float repeated_float = 11
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated double repeated_double = 12
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated bool repeated_bool = 13
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated TestAllTypes.NestedEnum repeated_nested_enum = 14
+      [features.repeated_field_encoding = EXPANDED];
 }

java/core/src/test/proto/com/google/protobuf/proto2_message.proto

@@ -6,82 +6,121 @@
 // https://developers.google.com/open-source/licenses/bsd
 
 // LINT: ALLOW_GROUPS
-syntax = "proto2";
+edition = "2023";
 
 package protobuf.experimental;
 
+option features.utf8_validation = NONE;
 option java_package = "com.google.protobuf.testing";
 option java_outer_classname = "Proto2Testing";
 
 message Proto2SpecialFieldName {
-  optional double regular_name = 1;
-  optional int32 cached_size = 2;
-  optional int64 serialized_size = 3;
-  optional string class = 4;
+  double regular_name = 1;
+  int32 cached_size = 2;
+  int64 serialized_size = 3;
+  string class = 4;
 }
 
 message Proto2Message {
 
   enum TestEnum {
+    option features.enum_type = CLOSED;
+
     ZERO = 0;
     ONE = 1;
     TWO = 2;
   }
 
-  optional double field_double_1 = 1;
-  optional float field_float_2 = 2;
-  optional int64 field_int64_3 = 3;
-  optional uint64 field_uint64_4 = 4;
-  optional int32 field_int32_5 = 5;
-  optional fixed64 field_fixed64_6 = 6;
-  optional fixed32 field_fixed32_7 = 7;
-  optional bool field_bool_8 = 8;
-  optional string field_string_9 = 9;
-  optional Proto2Message field_message_10 = 10;
-  optional bytes field_bytes_11 = 11;
-  optional uint32 field_uint32_12 = 12;
-  optional TestEnum field_enum_13 = 13;
-  optional sfixed32 field_sfixed32_14 = 14;
-  optional sfixed64 field_sfixed64_15 = 15;
-  optional sint32 field_sint32_16 = 16;
-  optional sint64 field_sint64_17 = 17;
-  repeated double field_double_list_18 = 18 [packed = false];
-  repeated float field_float_list_19 = 19 [packed = false];
-  repeated int64 field_int64_list_20 = 20 [packed = false];
-  repeated uint64 field_uint64_list_21 = 21 [packed = false];
-  repeated int32 field_int32_list_22 = 22 [packed = false];
-  repeated fixed64 field_fixed64_list_23 = 23 [packed = false];
-  repeated fixed32 field_fixed32_list_24 = 24 [packed = false];
-  repeated bool field_bool_list_25 = 25 [packed = false];
-  repeated string field_string_list_26 = 26 [packed = false];
-  repeated Proto2Message field_message_list_27 = 27 [packed = false];
-  repeated bytes field_bytes_list_28 = 28 [packed = false];
-  repeated uint32 field_uint32_list_29 = 29 [packed = false];
-  repeated TestEnum field_enum_list_30 = 30 [packed = false];
-  repeated sfixed32 field_sfixed32_list_31 = 31 [packed = false];
-  repeated sfixed64 field_sfixed64_list_32 = 32 [packed = false];
-  repeated sint32 field_sint32_list_33 = 33 [packed = false];
-  repeated sint64 field_sint64_list_34 = 34 [packed = false];
-  repeated double field_double_list_packed_35 = 35 [packed = true];
-  repeated float field_float_list_packed_36 = 36 [packed = true];
-  repeated int64 field_int64_list_packed_37 = 37 [packed = true];
-  repeated uint64 field_uint64_list_packed_38 = 38 [packed = true];
-  repeated int32 field_int32_list_packed_39 = 39 [packed = true];
-  repeated fixed64 field_fixed64_list_packed_40 = 40 [packed = true];
-  repeated fixed32 field_fixed32_list_packed_41 = 41 [packed = true];
-  repeated bool field_bool_list_packed_42 = 42 [packed = true];
-  repeated uint32 field_uint32_list_packed_43 = 43 [packed = true];
-  repeated TestEnum field_enum_list_packed_44 = 44 [packed = true];
-  repeated sfixed32 field_sfixed32_list_packed_45 = 45 [packed = true];
-  repeated sfixed64 field_sfixed64_list_packed_46 = 46 [packed = true];
-  repeated sint32 field_sint32_list_packed_47 = 47 [packed = true];
-  repeated sint64 field_sint64_list_packed_48 = 48 [packed = true];
-  optional group FieldGroup49 = 49 {
-    optional int32 field_int32_50 = 50;
+  double field_double_1 = 1;
+  float field_float_2 = 2;
+  int64 field_int64_3 = 3;
+  uint64 field_uint64_4 = 4;
+  int32 field_int32_5 = 5;
+  fixed64 field_fixed64_6 = 6;
+  fixed32 field_fixed32_7 = 7;
+  bool field_bool_8 = 8;
+  string field_string_9 = 9;
+  Proto2Message field_message_10 = 10;
+  bytes field_bytes_11 = 11;
+  uint32 field_uint32_12 = 12;
+  TestEnum field_enum_13 = 13;
+  sfixed32 field_sfixed32_14 = 14;
+  sfixed64 field_sfixed64_15 = 15;
+  sint32 field_sint32_16 = 16;
+  sint64 field_sint64_17 = 17;
+  repeated double field_double_list_18 = 18
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated float field_float_list_19 = 19
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated int64 field_int64_list_20 = 20
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated uint64 field_uint64_list_21 = 21
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated int32 field_int32_list_22 = 22
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated fixed64 field_fixed64_list_23 = 23
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated fixed32 field_fixed32_list_24 = 24
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated bool field_bool_list_25 = 25
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated string field_string_list_26 = 26;
+  repeated Proto2Message field_message_list_27 = 27;
+  repeated bytes field_bytes_list_28 = 28;
+  repeated uint32 field_uint32_list_29 = 29
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated TestEnum field_enum_list_30 = 30
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sfixed32 field_sfixed32_list_31 = 31
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sfixed64 field_sfixed64_list_32 = 32
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sint32 field_sint32_list_33 = 33
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sint64 field_sint64_list_34 = 34
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated double field_double_list_packed_35 = 35;
+  repeated float field_float_list_packed_36 = 36;
+  repeated int64 field_int64_list_packed_37 = 37;
+  repeated uint64 field_uint64_list_packed_38 = 38;
+  repeated int32 field_int32_list_packed_39 = 39;
+  repeated fixed64 field_fixed64_list_packed_40 = 40;
+  repeated fixed32 field_fixed32_list_packed_41 = 41;
+  repeated bool field_bool_list_packed_42 = 42;
+  repeated uint32 field_uint32_list_packed_43 = 43;
+  repeated TestEnum field_enum_list_packed_44 = 44;
+  repeated sfixed32 field_sfixed32_list_packed_45 = 45;
+  repeated sfixed64 field_sfixed64_list_packed_46 = 46;
+  repeated sint32 field_sint32_list_packed_47 = 47;
+  repeated sint64 field_sint64_list_packed_48 = 48;
+
+  message FieldGroup49 {
+    int32 field_int32_50 = 50;
   }
-  repeated group FieldGroupList51 = 51 {
-    optional int32 field_int32_52 = 52;
+
+  FieldGroup49 fieldgroup49 = 49 [features.message_encoding = DELIMITED];
+
+  message FieldGroupList51 {
+    int32 field_int32_52 = 52;
   }
+
+  repeated FieldGroupList51 fieldgrouplist51 = 51
+      [features.message_encoding = DELIMITED];
+
   oneof test_oneof {
     double field_double_53 = 53;
     float field_float_54 = 54;
@@ -99,35 +138,75 @@ message Proto2Message {
     sfixed64 field_sfixed64_66 = 66;
     sint32 field_sint32_67 = 67;
     sint64 field_sint64_68 = 68;
-    group FieldGroup69 = 69 {
-      optional int32 field_int32_70 = 70;
-    }
+    FieldGroup69 fieldgroup69 = 69 [features.message_encoding = DELIMITED];
+  }
+
+  message FieldGroup69 {
+    int32 field_int32_70 = 70;
   }
 
   message RequiredNestedMessage {
-    optional int32 value = 1;
+    int32 value = 1;
   }
 
-  required double field_required_double_71 = 71;
-  required float field_required_float_72 = 72;
-  required int64 field_required_int64_73 = 73;
-  required uint64 field_required_uint64_74 = 74;
-  required int32 field_required_int32_75 = 75;
-  required fixed64 field_required_fixed64_76 = 76;
-  required fixed32 field_required_fixed32_77 = 77;
-  required bool field_required_bool_78 = 78;
-  required string field_required_string_79 = 79;
-  required RequiredNestedMessage field_required_message_80 = 80;
-  required bytes field_required_bytes_81 = 81;
-  required uint32 field_required_uint32_82 = 82;
-  required TestEnum field_required_enum_83 = 83;
-  required sfixed32 field_required_sfixed32_84 = 84;
-  required sfixed64 field_required_sfixed64_85 = 85;
-  required sint32 field_required_sint32_86 = 86;
-  required sint64 field_required_sint64_87 = 87;
-  required group FieldRequiredGroup88 = 88 {
-    optional int32 field_int32_89 = 89;
+  double field_required_double_71 = 71
+      [features.field_presence = LEGACY_REQUIRED];
+
+  float field_required_float_72 = 72
+      [features.field_presence = LEGACY_REQUIRED];
+
+  int64 field_required_int64_73 = 73
+      [features.field_presence = LEGACY_REQUIRED];
+
+  uint64 field_required_uint64_74 = 74
+      [features.field_presence = LEGACY_REQUIRED];
+
+  int32 field_required_int32_75 = 75
+      [features.field_presence = LEGACY_REQUIRED];
+
+  fixed64 field_required_fixed64_76 = 76
+      [features.field_presence = LEGACY_REQUIRED];
+
+  fixed32 field_required_fixed32_77 = 77
+      [features.field_presence = LEGACY_REQUIRED];
+
+  bool field_required_bool_78 = 78 [features.field_presence = LEGACY_REQUIRED];
+
+  string field_required_string_79 = 79
+      [features.field_presence = LEGACY_REQUIRED];
+
+  RequiredNestedMessage field_required_message_80 = 80
+      [features.field_presence = LEGACY_REQUIRED];
+
+  bytes field_required_bytes_81 = 81
+      [features.field_presence = LEGACY_REQUIRED];
+
+  uint32 field_required_uint32_82 = 82
+      [features.field_presence = LEGACY_REQUIRED];
+
+  TestEnum field_required_enum_83 = 83
+      [features.field_presence = LEGACY_REQUIRED];
+
+  sfixed32 field_required_sfixed32_84 = 84
+      [features.field_presence = LEGACY_REQUIRED];
+
+  sfixed64 field_required_sfixed64_85 = 85
+      [features.field_presence = LEGACY_REQUIRED];
+
+  sint32 field_required_sint32_86 = 86
+      [features.field_presence = LEGACY_REQUIRED];
+
+  sint64 field_required_sint64_87 = 87
+      [features.field_presence = LEGACY_REQUIRED];
+
+  message FieldRequiredGroup88 {
+    int32 field_int32_89 = 89;
   }
+
+  FieldRequiredGroup88 fieldrequiredgroup88 = 88 [
+    features.field_presence = LEGACY_REQUIRED,
+    features.message_encoding = DELIMITED
+  ];
 }
 
 message Proto2Empty {}
@@ -137,65 +216,94 @@ message Proto2MessageWithExtensions {
 }
 
 extend Proto2MessageWithExtensions {
-  optional double field_double_1 = 1;
-  optional float field_float_2 = 2;
-  optional int64 field_int64_3 = 3;
-  optional uint64 field_uint64_4 = 4;
-  optional int32 field_int32_5 = 5;
-  optional fixed64 field_fixed64_6 = 6;
-  optional fixed32 field_fixed32_7 = 7;
-  optional bool field_bool_8 = 8;
-  optional string field_string_9 = 9;
-  optional Proto2Message field_message_10 = 10;
-  optional bytes field_bytes_11 = 11;
-  optional uint32 field_uint32_12 = 12;
-  optional Proto2Message.TestEnum field_enum_13 = 13;
-  optional sfixed32 field_sfixed32_14 = 14;
-  optional sfixed64 field_sfixed64_15 = 15;
-  optional sint32 field_sint32_16 = 16;
-  optional sint64 field_sint64_17 = 17;
-
-  repeated double field_double_list_18 = 18 [packed = false];
-  repeated float field_float_list_19 = 19 [packed = false];
-  repeated int64 field_int64_list_20 = 20 [packed = false];
-  repeated uint64 field_uint64_list_21 = 21 [packed = false];
-  repeated int32 field_int32_list_22 = 22 [packed = false];
-  repeated fixed64 field_fixed64_list_23 = 23 [packed = false];
-  repeated fixed32 field_fixed32_list_24 = 24 [packed = false];
-  repeated bool field_bool_list_25 = 25 [packed = false];
-  repeated string field_string_list_26 = 26 [packed = false];
-  repeated Proto2Message field_message_list_27 = 27 [packed = false];
-  repeated bytes field_bytes_list_28 = 28 [packed = false];
-  repeated uint32 field_uint32_list_29 = 29 [packed = false];
-  repeated Proto2Message.TestEnum field_enum_list_30 = 30 [packed = false];
-  repeated sfixed32 field_sfixed32_list_31 = 31 [packed = false];
-  repeated sfixed64 field_sfixed64_list_32 = 32 [packed = false];
-  repeated sint32 field_sint32_list_33 = 33 [packed = false];
-  repeated sint64 field_sint64_list_34 = 34 [packed = false];
-
-  repeated double field_double_list_packed_35 = 35 [packed = true];
-  repeated float field_float_list_packed_36 = 36 [packed = true];
-  repeated int64 field_int64_list_packed_37 = 37 [packed = true];
-  repeated uint64 field_uint64_list_packed_38 = 38 [packed = true];
-  repeated int32 field_int32_list_packed_39 = 39 [packed = true];
-  repeated fixed64 field_fixed64_list_packed_40 = 40 [packed = true];
-  repeated fixed32 field_fixed32_list_packed_41 = 41 [packed = true];
-  repeated bool field_bool_list_packed_42 = 42 [packed = true];
-  repeated uint32 field_uint32_list_packed_43 = 43 [packed = true];
-  repeated Proto2Message.TestEnum field_enum_list_packed_44 = 44
-      [packed = true];
-  repeated sfixed32 field_sfixed32_list_packed_45 = 45 [packed = true];
-  repeated sfixed64 field_sfixed64_list_packed_46 = 46 [packed = true];
-  repeated sint32 field_sint32_list_packed_47 = 47 [packed = true];
-  repeated sint64 field_sint64_list_packed_48 = 48 [packed = true];
-
-  optional group FieldGroup49 = 49 {
-    optional int32 field_int32_50 = 50;
-  }
+  double field_double_1 = 1;
+  float field_float_2 = 2;
+  int64 field_int64_3 = 3;
+  uint64 field_uint64_4 = 4;
+  int32 field_int32_5 = 5;
+  fixed64 field_fixed64_6 = 6;
+  fixed32 field_fixed32_7 = 7;
+  bool field_bool_8 = 8;
+  string field_string_9 = 9;
+  Proto2Message field_message_10 = 10;
+  bytes field_bytes_11 = 11;
+  uint32 field_uint32_12 = 12;
+  Proto2Message.TestEnum field_enum_13 = 13;
+  sfixed32 field_sfixed32_14 = 14;
+  sfixed64 field_sfixed64_15 = 15;
+  sint32 field_sint32_16 = 16;
+  sint64 field_sint64_17 = 17;
+  repeated double field_double_list_18 = 18
+      [features.repeated_field_encoding = EXPANDED];
 
-  repeated group FieldGroupList51 = 51 {
-    optional int32 field_int32_52 = 52;
-  }
+  repeated float field_float_list_19 = 19
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated int64 field_int64_list_20 = 20
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated uint64 field_uint64_list_21 = 21
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated int32 field_int32_list_22 = 22
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated fixed64 field_fixed64_list_23 = 23
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated fixed32 field_fixed32_list_24 = 24
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated bool field_bool_list_25 = 25
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated string field_string_list_26 = 26;
+  repeated Proto2Message field_message_list_27 = 27;
+  repeated bytes field_bytes_list_28 = 28;
+  repeated uint32 field_uint32_list_29 = 29
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated Proto2Message.TestEnum field_enum_list_30 = 30
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sfixed32 field_sfixed32_list_31 = 31
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sfixed64 field_sfixed64_list_32 = 32
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sint32 field_sint32_list_33 = 33
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sint64 field_sint64_list_34 = 34
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated double field_double_list_packed_35 = 35;
+  repeated float field_float_list_packed_36 = 36;
+  repeated int64 field_int64_list_packed_37 = 37;
+  repeated uint64 field_uint64_list_packed_38 = 38;
+  repeated int32 field_int32_list_packed_39 = 39;
+  repeated fixed64 field_fixed64_list_packed_40 = 40;
+  repeated fixed32 field_fixed32_list_packed_41 = 41;
+  repeated bool field_bool_list_packed_42 = 42;
+  repeated uint32 field_uint32_list_packed_43 = 43;
+  repeated Proto2Message.TestEnum field_enum_list_packed_44 = 44;
+  repeated sfixed32 field_sfixed32_list_packed_45 = 45;
+  repeated sfixed64 field_sfixed64_list_packed_46 = 46;
+  repeated sint32 field_sint32_list_packed_47 = 47;
+  repeated sint64 field_sint64_list_packed_48 = 48;
+  FieldGroup49 fieldgroup49 = 49 [features.message_encoding = DELIMITED];
+
+  repeated FieldGroupList51 fieldgrouplist51 = 51
+      [features.message_encoding = DELIMITED];
+}
+
+message FieldGroup49 {
+  int32 field_int32_50 = 50;
+}
+
+message FieldGroupList51 {
+  int32 field_int32_52 = 52;
 }
 
 message Proto2MessageWithMaps {

java/core/src/test/proto/com/google/protobuf/proto2_message_lite.proto

@@ -6,75 +6,114 @@
 // https://developers.google.com/open-source/licenses/bsd
 
 // LINT: ALLOW_GROUPS
-syntax = "proto2";
+edition = "2023";
 
 package protobuf.experimental.lite;
 
+option features.utf8_validation = NONE;
 option java_package = "com.google.protobuf.testing";
 option java_outer_classname = "Proto2TestingLite";
 
 message Proto2MessageLite {
 
   enum TestEnum {
+    option features.enum_type = CLOSED;
+
     ZERO = 0;
     ONE = 1;
     TWO = 2;
   }
 
-  optional double field_double_1 = 1;
-  optional float field_float_2 = 2;
-  optional int64 field_int64_3 = 3;
-  optional uint64 field_uint64_4 = 4;
-  optional int32 field_int32_5 = 5;
-  optional fixed64 field_fixed64_6 = 6;
-  optional fixed32 field_fixed32_7 = 7;
-  optional bool field_bool_8 = 8;
-  optional string field_string_9 = 9;
-  optional Proto2MessageLite field_message_10 = 10;
-  optional bytes field_bytes_11 = 11;
-  optional uint32 field_uint32_12 = 12;
-  optional TestEnum field_enum_13 = 13;
-  optional sfixed32 field_sfixed32_14 = 14;
-  optional sfixed64 field_sfixed64_15 = 15;
-  optional sint32 field_sint32_16 = 16;
-  optional sint64 field_sint64_17 = 17;
-  repeated double field_double_list_18 = 18 [packed = false];
-  repeated float field_float_list_19 = 19 [packed = false];
-  repeated int64 field_int64_list_20 = 20 [packed = false];
-  repeated uint64 field_uint64_list_21 = 21 [packed = false];
-  repeated int32 field_int32_list_22 = 22 [packed = false];
-  repeated fixed64 field_fixed64_list_23 = 23 [packed = false];
-  repeated fixed32 field_fixed32_list_24 = 24 [packed = false];
-  repeated bool field_bool_list_25 = 25 [packed = false];
-  repeated string field_string_list_26 = 26 [packed = false];
-  repeated Proto2MessageLite field_message_list_27 = 27 [packed = false];
-  repeated bytes field_bytes_list_28 = 28 [packed = false];
-  repeated uint32 field_uint32_list_29 = 29 [packed = false];
-  repeated TestEnum field_enum_list_30 = 30 [packed = false];
-  repeated sfixed32 field_sfixed32_list_31 = 31 [packed = false];
-  repeated sfixed64 field_sfixed64_list_32 = 32 [packed = false];
-  repeated sint32 field_sint32_list_33 = 33 [packed = false];
-  repeated sint64 field_sint64_list_34 = 34 [packed = false];
-  repeated double field_double_list_packed_35 = 35 [packed = true];
-  repeated float field_float_list_packed_36 = 36 [packed = true];
-  repeated int64 field_int64_list_packed_37 = 37 [packed = true];
-  repeated uint64 field_uint64_list_packed_38 = 38 [packed = true];
-  repeated int32 field_int32_list_packed_39 = 39 [packed = true];
-  repeated fixed64 field_fixed64_list_packed_40 = 40 [packed = true];
-  repeated fixed32 field_fixed32_list_packed_41 = 41 [packed = true];
-  repeated bool field_bool_list_packed_42 = 42 [packed = true];
-  repeated uint32 field_uint32_list_packed_43 = 43 [packed = true];
-  repeated TestEnum field_enum_list_packed_44 = 44 [packed = true];
-  repeated sfixed32 field_sfixed32_list_packed_45 = 45 [packed = true];
-  repeated sfixed64 field_sfixed64_list_packed_46 = 46 [packed = true];
-  repeated sint32 field_sint32_list_packed_47 = 47 [packed = true];
-  repeated sint64 field_sint64_list_packed_48 = 48 [packed = true];
-  optional group FieldGroup49 = 49 {
-    optional int32 field_int32_50 = 50;
+  double field_double_1 = 1;
+  float field_float_2 = 2;
+  int64 field_int64_3 = 3;
+  uint64 field_uint64_4 = 4;
+  int32 field_int32_5 = 5;
+  fixed64 field_fixed64_6 = 6;
+  fixed32 field_fixed32_7 = 7;
+  bool field_bool_8 = 8;
+  string field_string_9 = 9;
+  Proto2MessageLite field_message_10 = 10;
+  bytes field_bytes_11 = 11;
+  uint32 field_uint32_12 = 12;
+  TestEnum field_enum_13 = 13;
+  sfixed32 field_sfixed32_14 = 14;
+  sfixed64 field_sfixed64_15 = 15;
+  sint32 field_sint32_16 = 16;
+  sint64 field_sint64_17 = 17;
+  repeated double field_double_list_18 = 18
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated float field_float_list_19 = 19
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated int64 field_int64_list_20 = 20
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated uint64 field_uint64_list_21 = 21
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated int32 field_int32_list_22 = 22
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated fixed64 field_fixed64_list_23 = 23
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated fixed32 field_fixed32_list_24 = 24
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated bool field_bool_list_25 = 25
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated string field_string_list_26 = 26;
+  repeated Proto2MessageLite field_message_list_27 = 27;
+  repeated bytes field_bytes_list_28 = 28;
+  repeated uint32 field_uint32_list_29 = 29
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated TestEnum field_enum_list_30 = 30
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sfixed32 field_sfixed32_list_31 = 31
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sfixed64 field_sfixed64_list_32 = 32
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sint32 field_sint32_list_33 = 33
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sint64 field_sint64_list_34 = 34
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated double field_double_list_packed_35 = 35;
+  repeated float field_float_list_packed_36 = 36;
+  repeated int64 field_int64_list_packed_37 = 37;
+  repeated uint64 field_uint64_list_packed_38 = 38;
+  repeated int32 field_int32_list_packed_39 = 39;
+  repeated fixed64 field_fixed64_list_packed_40 = 40;
+  repeated fixed32 field_fixed32_list_packed_41 = 41;
+  repeated bool field_bool_list_packed_42 = 42;
+  repeated uint32 field_uint32_list_packed_43 = 43;
+  repeated TestEnum field_enum_list_packed_44 = 44;
+  repeated sfixed32 field_sfixed32_list_packed_45 = 45;
+  repeated sfixed64 field_sfixed64_list_packed_46 = 46;
+  repeated sint32 field_sint32_list_packed_47 = 47;
+  repeated sint64 field_sint64_list_packed_48 = 48;
+
+  message FieldGroup49 {
+    int32 field_int32_50 = 50;
   }
-  repeated group FieldGroupList51 = 51 {
-    optional int32 field_int32_52 = 52;
+
+  FieldGroup49 fieldgroup49 = 49 [features.message_encoding = DELIMITED];
+
+  message FieldGroupList51 {
+    int32 field_int32_52 = 52;
   }
+
+  repeated FieldGroupList51 fieldgrouplist51 = 51
+      [features.message_encoding = DELIMITED];
+
   oneof test_oneof {
     double field_double_53 = 53;
     float field_float_54 = 54;
@@ -92,35 +131,75 @@ message Proto2MessageLite {
     sfixed64 field_sfixed64_66 = 66;
     sint32 field_sint32_67 = 67;
     sint64 field_sint64_68 = 68;
-    group FieldGroup69 = 69 {
-      optional int32 field_int32_70 = 70;
-    }
+    FieldGroup69 fieldgroup69 = 69 [features.message_encoding = DELIMITED];
+  }
+
+  message FieldGroup69 {
+    int32 field_int32_70 = 70;
   }
 
   message RequiredNestedMessage {
-    optional int32 value = 1;
+    int32 value = 1;
   }
 
-  required double field_required_double_71 = 71;
-  required float field_required_float_72 = 72;
-  required int64 field_required_int64_73 = 73;
-  required uint64 field_required_uint64_74 = 74;
-  required int32 field_required_int32_75 = 75;
-  required fixed64 field_required_fixed64_76 = 76;
-  required fixed32 field_required_fixed32_77 = 77;
-  required bool field_required_bool_78 = 78;
-  required string field_required_string_79 = 79;
-  required RequiredNestedMessage field_required_message_80 = 80;
-  required bytes field_required_bytes_81 = 81;
-  required uint32 field_required_uint32_82 = 82;
-  required TestEnum field_required_enum_83 = 83;
-  required sfixed32 field_required_sfixed32_84 = 84;
-  required sfixed64 field_required_sfixed64_85 = 85;
-  required sint32 field_required_sint32_86 = 86;
-  required sint64 field_required_sint64_87 = 87;
-  required group FieldRequiredGroup88 = 88 {
-    optional int32 field_int32_89 = 89;
+  double field_required_double_71 = 71
+      [features.field_presence = LEGACY_REQUIRED];
+
+  float field_required_float_72 = 72
+      [features.field_presence = LEGACY_REQUIRED];
+
+  int64 field_required_int64_73 = 73
+      [features.field_presence = LEGACY_REQUIRED];
+
+  uint64 field_required_uint64_74 = 74
+      [features.field_presence = LEGACY_REQUIRED];
+
+  int32 field_required_int32_75 = 75
+      [features.field_presence = LEGACY_REQUIRED];
+
+  fixed64 field_required_fixed64_76 = 76
+      [features.field_presence = LEGACY_REQUIRED];
+
+  fixed32 field_required_fixed32_77 = 77
+      [features.field_presence = LEGACY_REQUIRED];
+
+  bool field_required_bool_78 = 78 [features.field_presence = LEGACY_REQUIRED];
+
+  string field_required_string_79 = 79
+      [features.field_presence = LEGACY_REQUIRED];
+
+  RequiredNestedMessage field_required_message_80 = 80
+      [features.field_presence = LEGACY_REQUIRED];
+
+  bytes field_required_bytes_81 = 81
+      [features.field_presence = LEGACY_REQUIRED];
+
+  uint32 field_required_uint32_82 = 82
+      [features.field_presence = LEGACY_REQUIRED];
+
+  TestEnum field_required_enum_83 = 83
+      [features.field_presence = LEGACY_REQUIRED];
+
+  sfixed32 field_required_sfixed32_84 = 84
+      [features.field_presence = LEGACY_REQUIRED];
+
+  sfixed64 field_required_sfixed64_85 = 85
+      [features.field_presence = LEGACY_REQUIRED];
+
+  sint32 field_required_sint32_86 = 86
+      [features.field_presence = LEGACY_REQUIRED];
+
+  sint64 field_required_sint64_87 = 87
+      [features.field_presence = LEGACY_REQUIRED];
+
+  message FieldRequiredGroup88 {
+    int32 field_int32_89 = 89;
   }
+
+  FieldRequiredGroup88 fieldrequiredgroup88 = 88 [
+    features.field_presence = LEGACY_REQUIRED,
+    features.message_encoding = DELIMITED
+  ];
 }
 
 message Proto2EmptyLite {}
@@ -130,65 +209,94 @@ message Proto2MessageLiteWithExtensions {
 }
 
 extend Proto2MessageLiteWithExtensions {
-  optional double field_double_1 = 1;
-  optional float field_float_2 = 2;
-  optional int64 field_int64_3 = 3;
-  optional uint64 field_uint64_4 = 4;
-  optional int32 field_int32_5 = 5;
-  optional fixed64 field_fixed64_6 = 6;
-  optional fixed32 field_fixed32_7 = 7;
-  optional bool field_bool_8 = 8;
-  optional string field_string_9 = 9;
-  optional Proto2MessageLite field_message_10 = 10;
-  optional bytes field_bytes_11 = 11;
-  optional uint32 field_uint32_12 = 12;
-  optional Proto2MessageLite.TestEnum field_enum_13 = 13;
-  optional sfixed32 field_sfixed32_14 = 14;
-  optional sfixed64 field_sfixed64_15 = 15;
-  optional sint32 field_sint32_16 = 16;
-  optional sint64 field_sint64_17 = 17;
-
-  repeated double field_double_list_18 = 18 [packed = false];
-  repeated float field_float_list_19 = 19 [packed = false];
-  repeated int64 field_int64_list_20 = 20 [packed = false];
-  repeated uint64 field_uint64_list_21 = 21 [packed = false];
-  repeated int32 field_int32_list_22 = 22 [packed = false];
-  repeated fixed64 field_fixed64_list_23 = 23 [packed = false];
-  repeated fixed32 field_fixed32_list_24 = 24 [packed = false];
-  repeated bool field_bool_list_25 = 25 [packed = false];
-  repeated string field_string_list_26 = 26 [packed = false];
-  repeated Proto2MessageLite field_message_list_27 = 27 [packed = false];
-  repeated bytes field_bytes_list_28 = 28 [packed = false];
-  repeated uint32 field_uint32_list_29 = 29 [packed = false];
-  repeated Proto2MessageLite.TestEnum field_enum_list_30 = 30 [packed = false];
-  repeated sfixed32 field_sfixed32_list_31 = 31 [packed = false];
-  repeated sfixed64 field_sfixed64_list_32 = 32 [packed = false];
-  repeated sint32 field_sint32_list_33 = 33 [packed = false];
-  repeated sint64 field_sint64_list_34 = 34 [packed = false];
-
-  repeated double field_double_list_packed_35 = 35 [packed = true];
-  repeated float field_float_list_packed_36 = 36 [packed = true];
-  repeated int64 field_int64_list_packed_37 = 37 [packed = true];
-  repeated uint64 field_uint64_list_packed_38 = 38 [packed = true];
-  repeated int32 field_int32_list_packed_39 = 39 [packed = true];
-  repeated fixed64 field_fixed64_list_packed_40 = 40 [packed = true];
-  repeated fixed32 field_fixed32_list_packed_41 = 41 [packed = true];
-  repeated bool field_bool_list_packed_42 = 42 [packed = true];
-  repeated uint32 field_uint32_list_packed_43 = 43 [packed = true];
-  repeated Proto2MessageLite.TestEnum field_enum_list_packed_44 = 44
-      [packed = true];
-  repeated sfixed32 field_sfixed32_list_packed_45 = 45 [packed = true];
-  repeated sfixed64 field_sfixed64_list_packed_46 = 46 [packed = true];
-  repeated sint32 field_sint32_list_packed_47 = 47 [packed = true];
-  repeated sint64 field_sint64_list_packed_48 = 48 [packed = true];
-
-  optional group FieldGroup49 = 49 {
-    optional int32 field_int32_50 = 50;
-  }
+  double field_double_1 = 1;
+  float field_float_2 = 2;
+  int64 field_int64_3 = 3;
+  uint64 field_uint64_4 = 4;
+  int32 field_int32_5 = 5;
+  fixed64 field_fixed64_6 = 6;
+  fixed32 field_fixed32_7 = 7;
+  bool field_bool_8 = 8;
+  string field_string_9 = 9;
+  Proto2MessageLite field_message_10 = 10;
+  bytes field_bytes_11 = 11;
+  uint32 field_uint32_12 = 12;
+  Proto2MessageLite.TestEnum field_enum_13 = 13;
+  sfixed32 field_sfixed32_14 = 14;
+  sfixed64 field_sfixed64_15 = 15;
+  sint32 field_sint32_16 = 16;
+  sint64 field_sint64_17 = 17;
+  repeated double field_double_list_18 = 18
+      [features.repeated_field_encoding = EXPANDED];
 
-  repeated group FieldGroupList51 = 51 {
-    optional int32 field_int32_52 = 52;
-  }
+  repeated float field_float_list_19 = 19
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated int64 field_int64_list_20 = 20
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated uint64 field_uint64_list_21 = 21
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated int32 field_int32_list_22 = 22
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated fixed64 field_fixed64_list_23 = 23
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated fixed32 field_fixed32_list_24 = 24
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated bool field_bool_list_25 = 25
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated string field_string_list_26 = 26;
+  repeated Proto2MessageLite field_message_list_27 = 27;
+  repeated bytes field_bytes_list_28 = 28;
+  repeated uint32 field_uint32_list_29 = 29
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated Proto2MessageLite.TestEnum field_enum_list_30 = 30
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sfixed32 field_sfixed32_list_31 = 31
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sfixed64 field_sfixed64_list_32 = 32
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sint32 field_sint32_list_33 = 33
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sint64 field_sint64_list_34 = 34
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated double field_double_list_packed_35 = 35;
+  repeated float field_float_list_packed_36 = 36;
+  repeated int64 field_int64_list_packed_37 = 37;
+  repeated uint64 field_uint64_list_packed_38 = 38;
+  repeated int32 field_int32_list_packed_39 = 39;
+  repeated fixed64 field_fixed64_list_packed_40 = 40;
+  repeated fixed32 field_fixed32_list_packed_41 = 41;
+  repeated bool field_bool_list_packed_42 = 42;
+  repeated uint32 field_uint32_list_packed_43 = 43;
+  repeated Proto2MessageLite.TestEnum field_enum_list_packed_44 = 44;
+  repeated sfixed32 field_sfixed32_list_packed_45 = 45;
+  repeated sfixed64 field_sfixed64_list_packed_46 = 46;
+  repeated sint32 field_sint32_list_packed_47 = 47;
+  repeated sint64 field_sint64_list_packed_48 = 48;
+  FieldGroup49 fieldgroup49 = 49 [features.message_encoding = DELIMITED];
+
+  repeated FieldGroupList51 fieldgrouplist51 = 51
+      [features.message_encoding = DELIMITED];
+}
+
+message FieldGroup49 {
+  int32 field_int32_50 = 50;
+}
+
+message FieldGroupList51 {
+  int32 field_int32_52 = 52;
 }
 
 message Proto2MessageLiteWithMaps {

java/core/src/test/proto/com/google/protobuf/proto2_text_format_performance_test.proto

@@ -5,15 +5,16 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-syntax = "proto2";
+edition = "2023";
 
 package protobuf.testing.textformat.performance.proto2;
 
+option features.repeated_field_encoding = EXPANDED;
 option java_package = "com.google.protobuf.testing.textformat.performance.proto2";
 option java_outer_classname = "Proto2TextFormatPerformanceProto";
 
 message ContainsSubMessageWithRepeatedInt32 {
-  optional RepeatedInt32 sub_msg = 1;
+  RepeatedInt32 sub_msg = 1;
 }
 
 message RepeatedInt32 {
@@ -25,5 +26,5 @@ message ContainsExtensionSubMessage {
 }
 
 extend ContainsExtensionSubMessage {
-  optional RepeatedInt32 sub_msg_ext = 1;
+  RepeatedInt32 sub_msg_ext = 1;
 }

java/core/src/test/proto/com/google/protobuf/proto2_unknown_enum_values.proto

@@ -5,10 +5,11 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-syntax = "proto2";
+edition = "2023";
 
 package proto2_unknown_enum_values;
 
+option features.enum_type = CLOSED;
 option java_package = "com.google.protobuf";
 option java_outer_classname = "Proto2UnknownEnumValuesTestProto";
 
@@ -19,7 +20,7 @@ enum Proto2TestEnum {
 }
 
 message Proto2EnumMessage {
-  repeated Proto2TestEnum repeated_packed_enum = 1 [packed = true];
+  repeated Proto2TestEnum repeated_packed_enum = 1;
 }
 
 // An enum containing a subset of the values of Proto2TestEnum, to test
@@ -27,11 +28,12 @@ message Proto2EnumMessage {
 enum Proto2TestEnumSubset {
   TESTENUM_SUBSET_ZERO = 0;
   TESTENUM_SUBSET_ONE = 1;
+
   // No enum value with number 2.
 }
 
 // Test messages for packed enum, with identical field number as
 // Proto2Message, to test parsing unknown packed enums.
 message Proto2EnumMessageWithEnumSubset {
-  repeated Proto2TestEnumSubset repeated_packed_enum = 1 [packed = true];
+  repeated Proto2TestEnumSubset repeated_packed_enum = 1;
 }

java/core/src/test/proto/com/google/protobuf/proto3_message.proto

@@ -5,10 +5,11 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-syntax = "proto3";
+edition = "2023";
 
 package protobuf.experimental;
 
+option features.field_presence = IMPLICIT;
 option java_package = "com.google.protobuf.testing";
 option java_outer_classname = "Proto3Testing";
 
@@ -43,37 +44,72 @@ message Proto3Message {
   sfixed64 field_sfixed64_15 = 15;
   sint32 field_sint32_16 = 16;
   sint64 field_sint64_17 = 17;
-  repeated double field_double_list_18 = 18 [packed = false];
-  repeated float field_float_list_19 = 19 [packed = false];
-  repeated int64 field_int64_list_20 = 20 [packed = false];
-  repeated uint64 field_uint64_list_21 = 21 [packed = false];
-  repeated int32 field_int32_list_22 = 22 [packed = false];
-  repeated fixed64 field_fixed64_list_23 = 23 [packed = false];
-  repeated fixed32 field_fixed32_list_24 = 24 [packed = false];
-  repeated bool field_bool_list_25 = 25 [packed = false];
-  repeated string field_string_list_26 = 26 [packed = false];
-  repeated Proto3Message field_message_list_27 = 27 [packed = false];
-  repeated bytes field_bytes_list_28 = 28 [packed = false];
-  repeated uint32 field_uint32_list_29 = 29 [packed = false];
-  repeated TestEnum field_enum_list_30 = 30 [packed = false];
-  repeated sfixed32 field_sfixed32_list_31 = 31 [packed = false];
-  repeated sfixed64 field_sfixed64_list_32 = 32 [packed = false];
-  repeated sint32 field_sint32_list_33 = 33 [packed = false];
-  repeated sint64 field_sint64_list_34 = 34 [packed = false];
-  repeated double field_double_list_packed_35 = 35 [packed = true];
-  repeated float field_float_list_packed_36 = 36 [packed = true];
-  repeated int64 field_int64_list_packed_37 = 37 [packed = true];
-  repeated uint64 field_uint64_list_packed_38 = 38 [packed = true];
-  repeated int32 field_int32_list_packed_39 = 39 [packed = true];
-  repeated fixed64 field_fixed64_list_packed_40 = 40 [packed = true];
-  repeated fixed32 field_fixed32_list_packed_41 = 41 [packed = true];
-  repeated bool field_bool_list_packed_42 = 42 [packed = true];
-  repeated uint32 field_uint32_list_packed_43 = 43 [packed = true];
-  repeated TestEnum field_enum_list_packed_44 = 44 [packed = true];
-  repeated sfixed32 field_sfixed32_list_packed_45 = 45 [packed = true];
-  repeated sfixed64 field_sfixed64_list_packed_46 = 46 [packed = true];
-  repeated sint32 field_sint32_list_packed_47 = 47 [packed = true];
-  repeated sint64 field_sint64_list_packed_48 = 48 [packed = true];
+  repeated double field_double_list_18 = 18
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated float field_float_list_19 = 19
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated int64 field_int64_list_20 = 20
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated uint64 field_uint64_list_21 = 21
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated int32 field_int32_list_22 = 22
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated fixed64 field_fixed64_list_23 = 23
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated fixed32 field_fixed32_list_24 = 24
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated bool field_bool_list_25 = 25
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated string field_string_list_26 = 26
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated Proto3Message field_message_list_27 = 27
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated bytes field_bytes_list_28 = 28
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated uint32 field_uint32_list_29 = 29
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated TestEnum field_enum_list_30 = 30
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sfixed32 field_sfixed32_list_31 = 31
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sfixed64 field_sfixed64_list_32 = 32
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sint32 field_sint32_list_33 = 33
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sint64 field_sint64_list_34 = 34
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated double field_double_list_packed_35 = 35;
+  repeated float field_float_list_packed_36 = 36;
+  repeated int64 field_int64_list_packed_37 = 37;
+  repeated uint64 field_uint64_list_packed_38 = 38;
+  repeated int32 field_int32_list_packed_39 = 39;
+  repeated fixed64 field_fixed64_list_packed_40 = 40;
+  repeated fixed32 field_fixed32_list_packed_41 = 41;
+  repeated bool field_bool_list_packed_42 = 42;
+  repeated uint32 field_uint32_list_packed_43 = 43;
+  repeated TestEnum field_enum_list_packed_44 = 44;
+  repeated sfixed32 field_sfixed32_list_packed_45 = 45;
+  repeated sfixed64 field_sfixed64_list_packed_46 = 46;
+  repeated sint32 field_sint32_list_packed_47 = 47;
+  repeated sint64 field_sint64_list_packed_48 = 48;
+
   oneof test_oneof {
     double field_double_53 = 53;
     float field_float_54 = 54;

java/core/src/test/proto/com/google/protobuf/proto3_message_lite.proto

@@ -5,10 +5,11 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-syntax = "proto3";
+edition = "2023";
 
 package protobuf.experimental;
 
+option features.field_presence = IMPLICIT;
 option java_package = "com.google.protobuf.testing";
 option java_outer_classname = "Proto3TestingLite";
 
@@ -36,37 +37,72 @@ message Proto3MessageLite {
   sfixed64 field_sfixed64_15 = 15;
   sint32 field_sint32_16 = 16;
   sint64 field_sint64_17 = 17;
-  repeated double field_double_list_18 = 18 [packed = false];
-  repeated float field_float_list_19 = 19 [packed = false];
-  repeated int64 field_int64_list_20 = 20 [packed = false];
-  repeated uint64 field_uint64_list_21 = 21 [packed = false];
-  repeated int32 field_int32_list_22 = 22 [packed = false];
-  repeated fixed64 field_fixed64_list_23 = 23 [packed = false];
-  repeated fixed32 field_fixed32_list_24 = 24 [packed = false];
-  repeated bool field_bool_list_25 = 25 [packed = false];
-  repeated string field_string_list_26 = 26 [packed = false];
-  repeated Proto3MessageLite field_message_list_27 = 27 [packed = false];
-  repeated bytes field_bytes_list_28 = 28 [packed = false];
-  repeated uint32 field_uint32_list_29 = 29 [packed = false];
-  repeated TestEnum field_enum_list_30 = 30 [packed = false];
-  repeated sfixed32 field_sfixed32_list_31 = 31 [packed = false];
-  repeated sfixed64 field_sfixed64_list_32 = 32 [packed = false];
-  repeated sint32 field_sint32_list_33 = 33 [packed = false];
-  repeated sint64 field_sint64_list_34 = 34 [packed = false];
-  repeated double field_double_list_packed_35 = 35 [packed = true];
-  repeated float field_float_list_packed_36 = 36 [packed = true];
-  repeated int64 field_int64_list_packed_37 = 37 [packed = true];
-  repeated uint64 field_uint64_list_packed_38 = 38 [packed = true];
-  repeated int32 field_int32_list_packed_39 = 39 [packed = true];
-  repeated fixed64 field_fixed64_list_packed_40 = 40 [packed = true];
-  repeated fixed32 field_fixed32_list_packed_41 = 41 [packed = true];
-  repeated bool field_bool_list_packed_42 = 42 [packed = true];
-  repeated uint32 field_uint32_list_packed_43 = 43 [packed = true];
-  repeated TestEnum field_enum_list_packed_44 = 44 [packed = true];
-  repeated sfixed32 field_sfixed32_list_packed_45 = 45 [packed = true];
-  repeated sfixed64 field_sfixed64_list_packed_46 = 46 [packed = true];
-  repeated sint32 field_sint32_list_packed_47 = 47 [packed = true];
-  repeated sint64 field_sint64_list_packed_48 = 48 [packed = true];
+  repeated double field_double_list_18 = 18
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated float field_float_list_19 = 19
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated int64 field_int64_list_20 = 20
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated uint64 field_uint64_list_21 = 21
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated int32 field_int32_list_22 = 22
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated fixed64 field_fixed64_list_23 = 23
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated fixed32 field_fixed32_list_24 = 24
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated bool field_bool_list_25 = 25
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated string field_string_list_26 = 26
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated Proto3MessageLite field_message_list_27 = 27
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated bytes field_bytes_list_28 = 28
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated uint32 field_uint32_list_29 = 29
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated TestEnum field_enum_list_30 = 30
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sfixed32 field_sfixed32_list_31 = 31
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sfixed64 field_sfixed64_list_32 = 32
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sint32 field_sint32_list_33 = 33
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated sint64 field_sint64_list_34 = 34
+      [features.repeated_field_encoding = EXPANDED];
+
+  repeated double field_double_list_packed_35 = 35;
+  repeated float field_float_list_packed_36 = 36;
+  repeated int64 field_int64_list_packed_37 = 37;
+  repeated uint64 field_uint64_list_packed_38 = 38;
+  repeated int32 field_int32_list_packed_39 = 39;
+  repeated fixed64 field_fixed64_list_packed_40 = 40;
+  repeated fixed32 field_fixed32_list_packed_41 = 41;
+  repeated bool field_bool_list_packed_42 = 42;
+  repeated uint32 field_uint32_list_packed_43 = 43;
+  repeated TestEnum field_enum_list_packed_44 = 44;
+  repeated sfixed32 field_sfixed32_list_packed_45 = 45;
+  repeated sfixed64 field_sfixed64_list_packed_46 = 46;
+  repeated sint32 field_sint32_list_packed_47 = 47;
+  repeated sint64 field_sint64_list_packed_48 = 48;
+
   oneof test_oneof {
     double field_double_53 = 53;
     float field_float_54 = 54;

java/core/src/test/proto/com/google/protobuf/proto3_text_format_performance_test.proto

@@ -5,7 +5,7 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-syntax = "proto3";
+edition = "2023";
 
 package protobuf.testing.textformat.performance.proto3;
 
@@ -13,7 +13,7 @@ option java_package = "com.google.protobuf.testing.textformat.performance.proto3
 option java_outer_classname = "Proto3TextFormatPerformanceProto";
 
 message ContainsSubMessageWithRepeatedInt32 {
-  optional RepeatedInt32 sub_msg = 1;
+  RepeatedInt32 sub_msg = 1;
 }
 
 message RepeatedInt32 {

java/core/src/test/proto/com/google/protobuf/test_bad_identifiers.proto

@@ -11,10 +11,13 @@
 // though the same identifiers are used internally by the java code generator.
 // LINT: LEGACY_NAMES
 
-syntax = "proto2";
+edition = "2023";
 
 package io_protocol_tests;
 
+option features.repeated_field_encoding = EXPANDED;
+option features.utf8_validation = NONE;
+option features.enum_type = CLOSED;
 option java_generic_services = true;  // auto-added
 option java_package = "com.google.protobuf";
 option java_outer_classname = "TestBadIdentifiersProto";
@@ -24,19 +27,19 @@ option java_outer_classname = "TestBadIdentifiersProto";
 // src/google/protobuf/compiler/java/java_helpers.cc
 message ForbiddenWordsUnderscoreMessage {
   // java.lang.Object
-  optional bool class = 1;
+  bool class = 1;
   // com.google.protobuf.MessageLiteOrBuilder
-  optional bool default_instance_for_type = 2;
+  bool default_instance_for_type = 2;
   // com.google.protobuf.MessageLite
-  optional bool parser_for_type = 3;
-  optional bool serialized_size = 4;
+  bool parser_for_type = 3;
+  bool serialized_size = 4;
   // com.google.protobuf.MessageOrBuilder
-  optional bool all_fields = 5;
-  optional bool descriptor_for_type = 6;
-  optional bool initialization_error_string = 7;
-  optional bool unknown_fields = 8;
+  bool all_fields = 5;
+  bool descriptor_for_type = 6;
+  bool initialization_error_string = 7;
+  bool unknown_fields = 8;
   // obsolete. kept for backwards compatibility of generated code
-  optional bool cached_size = 9;
+  bool cached_size = 9;
 }
 
 // Message with field names using leading underscores that conflict with
@@ -44,20 +47,20 @@ message ForbiddenWordsUnderscoreMessage {
 // src/google/protobuf/compiler/java/java_helpers.cc
 message ForbiddenWordsLeadingUnderscoreMessage {
   // java.lang.Object
-  optional bool _class = 1;
+  bool _class = 1;
   // com.google.protobuf.MessageLiteOrBuilder
-  optional bool _default_instance_for_type = 2;
+  bool _default_instance_for_type = 2;
   // com.google.protobuf.MessageLite
-  optional bool _parser_for_type = 3;
-  optional bool _serialized_size = 4;
+  bool _parser_for_type = 3;
+  bool _serialized_size = 4;
   // com.google.protobuf.MessageOrBuilder
-  optional bool _all_fields = 5;
-  optional bool _descriptor_for_type = 6;
-  optional bool _initialization_error_string = 7;
+  bool _all_fields = 5;
+  bool _descriptor_for_type = 6;
+  bool _initialization_error_string = 7;
   // TODO: re-enable
-  // optional bool _unknown_fields = 8;
+  // bool _unknown_fields = 8;
   // obsolete. kept for backwards compatibility of generated code
-  optional bool _cached_size = 9;
+  bool _cached_size = 9;
 }
 
 // Message with field names in camel case that conflict with accessors in the
@@ -65,32 +68,32 @@ message ForbiddenWordsLeadingUnderscoreMessage {
 // src/google/protobuf/compiler/java/java_helpers.cc
 message ForbiddenWordsCamelMessage {
   // java.lang.Object
-  optional bool class = 1;
+  bool class = 1;
   // com.google.protobuf.MessageLiteOrBuilder
-  optional bool defaultInstanceForType = 2;
+  bool defaultInstanceForType = 2;
   // com.google.protobuf.MessageLite
-  optional bool serializedSize = 3;
-  optional bool parserForType = 4;
+  bool serializedSize = 3;
+  bool parserForType = 4;
   // com.google.protobuf.MessageOrBuilder:
-  optional bool initializationErrorString = 5;
-  optional bool descriptorForType = 6;
-  optional bool allFields = 7;
+  bool initializationErrorString = 5;
+  bool descriptorForType = 6;
+  bool allFields = 7;
   // TODO: re-enable
-  // optional bool unknownFields = 8;
+  // bool unknownFields = 8;
   // obsolete. kept for backwards compatibility of generated code
-  optional bool cachedSize = 9;
+  bool cachedSize = 9;
 }
 
 message Descriptor {
   option no_standard_descriptor_accessor = true;
 
-  optional string descriptor = 1;
+  string descriptor = 1;
   message NestedDescriptor {
     option no_standard_descriptor_accessor = true;
 
-    optional string descriptor = 1;
+    string descriptor = 1;
   }
-  optional NestedDescriptor nested_descriptor = 2;
+  NestedDescriptor nested_descriptor = 2;
   enum NestedEnum {
     UNKNOWN = 0;
     FOO = 1;
@@ -102,7 +105,7 @@ message Parser {
     UNKNOWN = 0;
     PARSER = 1;
   }
-  optional ParserEnum parser = 1;
+  ParserEnum parser = 1;
 }
 
 message Deprecated {
@@ -114,38 +117,38 @@ message Deprecated {
     BAR = 2 [deprecated = true];
   }
 
-  optional int32 field1 = 1 [deprecated = true];
-  optional TestEnum field2 = 2 [deprecated = true];
-  optional ForbiddenWordsUnderscoreMessage field3 = 3 [deprecated = true];
+  int32 field1 = 1 [deprecated = true];
+  TestEnum field2 = 2 [deprecated = true];
+  ForbiddenWordsUnderscoreMessage field3 = 3 [deprecated = true];
 }
 
 message Override {
-  optional int32 override = 1;
+  int32 override = 1;
 }
 
 message Object {
-  optional int32 object = 1;
-  optional string string_object = 2;
+  int32 object = 1;
+  string string_object = 2;
 }
 
 message String {
-  optional string string = 1;
+  string string = 1;
 }
 
 message Integer {
-  optional int32 integer = 1;
+  int32 integer = 1;
 }
 
 message Long {
-  optional int32 long = 1;
+  int32 long = 1;
 }
 
 message Float {
-  optional float float = 1;
+  float float = 1;
 }
 
 message Double {
-  optional double double = 1;
+  double double = 1;
 }
 
 service TestConflictingMethodNames {
@@ -168,11 +171,11 @@ message TestConflictingFieldNames {
   repeated bytes bytes_field = 4;
   repeated ForbiddenWordsUnderscoreMessage message_field = 5;
 
-  optional int32 int32_field_count = 11;
-  optional TestEnum enum_field_count = 12;
-  optional string string_field_count = 13;
-  optional bytes bytes_field_count = 14;
-  optional ForbiddenWordsUnderscoreMessage message_field_count = 15;
+  int32 int32_field_count = 11;
+  TestEnum enum_field_count = 12;
+  string string_field_count = 13;
+  bytes bytes_field_count = 14;
+  ForbiddenWordsUnderscoreMessage message_field_count = 15;
 
   repeated int32 Int32Field = 21;                              // NO_PROTO3
   repeated TestEnum EnumField = 22;                            // NO_PROTO3
@@ -182,13 +185,14 @@ message TestConflictingFieldNames {
 
   // This field conflicts with "int32_field" as they both generate
   // the method getInt32FieldList().
-  required int32 int32_field_list = 31;  // NO_PROTO3
+  int32 int32_field_list = 31
+      [features.field_presence = LEGACY_REQUIRED];  // NO_PROTO3
 
   // These field pairs have the same Java converted name
-  optional string field_name = 32;   // NO_PROTO3
-  optional string field__name = 33;  // NO_PROTO3
-  optional int32 _2conflict = 34;    // NO_PROTO3
-  optional int32 __2conflict = 35;
+  string field_name = 32;   // NO_PROTO3
+  string field__name = 33;  // NO_PROTO3
+  int32 _2conflict = 34;    // NO_PROTO3
+  int32 __2conflict = 35;
 
   extensions 1000 to max;  // NO_PROTO3
 
@@ -196,9 +200,9 @@ message TestConflictingFieldNames {
   extend TestConflictingFieldNames {  // NO_PROTO3
     // We don't generate accessors for extensions so the following extension
     // fields don't conflict with the repeated field "int64_field".
-    optional int64 int64_field_count = 1001;  // NO_PROTO3
-    optional int64 int64_field_list = 1002;   // NO_PROTO3
-  }                                           // NO_PROTO3
+    int64 int64_field_count = 1001;  // NO_PROTO3
+    int64 int64_field_list = 1002;   // NO_PROTO3
+  }  // NO_PROTO3
 }
 
 message TestMapField {
@@ -210,12 +214,12 @@ message TestMapField {
 }
 
 message TestLeadingNumberFields {
-  optional int32 _30day_impressions = 1;
+  int32 _30day_impressions = 1;
   repeated string _60day_impressions = 2;
 
-  optional string __2_underscores = 3;
+  string __2_underscores = 3;
   repeated string __2repeated_underscores = 4;
 
-  optional int32 _32 = 32;
+  int32 _32 = 32;
   repeated int64 _64 = 64;
 }

java/core/src/test/proto/com/google/protobuf/test_check_utf8.proto

@@ -8,21 +8,23 @@
 // Author: Jacob Butcher (jbaum@google.com)
 //
 // Test file option java_string_check_utf8.
-syntax = "proto2";
+edition = "2023";
 
 package proto2_test_check_utf8;
 
+option features.utf8_validation = VERIFY;
 option java_outer_classname = "TestCheckUtf8";
-option java_string_check_utf8 = true;
 
 message StringWrapper {
-  required string req = 1;
-  optional string opt = 2;
+  string req = 1 [features.field_presence = LEGACY_REQUIRED];
+
+  string opt = 2;
   repeated string rep = 3;
 }
 
 message BytesWrapper {
-  required bytes req = 1;
-  optional bytes opt = 2;
+  bytes req = 1 [features.field_presence = LEGACY_REQUIRED];
+
+  bytes opt = 2;
   repeated bytes rep = 3;
 }

java/core/src/test/proto/com/google/protobuf/test_check_utf8_size.proto

@@ -8,22 +8,24 @@
 // Author: Jacob Butcher (jbaum@google.com)
 //
 // Test file option java_string_check_utf8.
-syntax = "proto2";
+edition = "2023";
 
 package proto2_test_check_utf8_size;
 
+option features.utf8_validation = VERIFY;
 option java_outer_classname = "TestCheckUtf8Size";
-option java_string_check_utf8 = true;
 option optimize_for = CODE_SIZE;
 
 message StringWrapperSize {
-  required string req = 1;
-  optional string opt = 2;
+  string req = 1 [features.field_presence = LEGACY_REQUIRED];
+
+  string opt = 2;
   repeated string rep = 3;
 }
 
 message BytesWrapperSize {
-  required bytes req = 1;
-  optional bytes opt = 2;
+  bytes req = 1 [features.field_presence = LEGACY_REQUIRED];
+
+  bytes opt = 2;
   repeated bytes rep = 3;
 }

java/core/src/test/proto/com/google/protobuf/wrappers_test.proto

@@ -5,12 +5,13 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-syntax = "proto3";
+edition = "2023";
 
 package wrappers_test;
 
 import "google/protobuf/wrappers.proto";
 
+option features.field_presence = IMPLICIT;
 option java_package = "com.google.protobuf.wrapperstest";
 option java_outer_classname = "WrappersTestProto";
 

java/kotlin-lite/BUILD.bazel

@@ -22,6 +22,7 @@ internal_gen_kt_protos(
     deps = [
         "//:any_proto",
         "//:api_proto",
+        "//:descriptor_proto",
         "//:duration_proto",
         "//:empty_proto",
         "//:field_mask_proto",
@@ -30,6 +31,7 @@ internal_gen_kt_protos(
         "//:timestamp_proto",
         "//:type_proto",
         "//:wrappers_proto",
+        "//java/core:java_features_proto",
     ],
 )
 
@@ -53,7 +55,11 @@ kt_jvm_export(
     ],
     maven_coordinates = "com.google.protobuf:protobuf-kotlin-lite:%s" % PROTOBUF_JAVA_VERSION,
     pom_template = "//java/kotlin-lite:pom_template.xml",
-    resources = ["//:well_known_type_protos"],
+    resources = [
+        "//:well_known_type_protos",
+        "//java/core:java_features_proto",
+        "//src/google/protobuf:descriptor_proto_srcs",
+    ],
     tags = ["manual"],
     runtime_deps = [
         ":lite_extensions",

java/kotlin-lite/generate-sources-build.xml

@@ -4,8 +4,11 @@
     <exec executable="${protoc}">
         <arg value="--kotlin_out=lite:${generated.sources.dir}"/>
         <arg value="--proto_path=${protobuf.source.dir}"/>
+        <arg value="--proto_path=${protobuf.java_source.dir}"/>
+        <arg value="${protobuf.java_source.dir}/main/java/com/google/protobuf/java_features.proto"/>
         <arg value="${protobuf.source.dir}/google/protobuf/any.proto"/>
         <arg value="${protobuf.source.dir}/google/protobuf/api.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/descriptor.proto"/>
         <arg value="${protobuf.source.dir}/google/protobuf/duration.proto"/>
         <arg value="${protobuf.source.dir}/google/protobuf/empty.proto"/>
         <arg value="${protobuf.source.dir}/google/protobuf/field_mask.proto"/>

java/lite/BUILD.bazel

@@ -24,6 +24,7 @@ proto_lang_toolchain(
     name = "toolchain",
     # keep this in sync w/ LITE_WELL_KNOWN_PROTO_MAP in //:BUILD
     blacklisted_protos = [
+        "//java/core:java_features_proto",
         "//:any_proto",
         "//:api_proto",
         "//:duration_proto",
@@ -60,6 +61,7 @@ build_test(
 conformance_test(
     name = "conformance_test",
     failure_list = "//conformance:failure_list_java_lite.txt",
+    maximum_edition = "2023",
     testee = "//conformance:conformance_java_lite",
     text_format_failure_list = "//conformance:text_format_failure_list_java_lite.txt",
 )

java/lite/generate-sources-build.xml

@@ -4,8 +4,11 @@
     <exec executable="${protoc}">
         <arg value="--java_out=lite:${generated.sources.dir}"/>
         <arg value="--proto_path=${protobuf.source.dir}"/>
+        <arg value="--proto_path=${protobuf.java_source.dir}"/>
+        <arg value="${protobuf.java_source.dir}/main/java/com/google/protobuf/java_features.proto"/>
         <arg value="${protobuf.source.dir}/google/protobuf/any.proto"/>
         <arg value="${protobuf.source.dir}/google/protobuf/api.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/descriptor.proto"/>
         <arg value="${protobuf.source.dir}/google/protobuf/duration.proto"/>
         <arg value="${protobuf.source.dir}/google/protobuf/empty.proto"/>
         <arg value="${protobuf.source.dir}/google/protobuf/field_mask.proto"/>

java/lite/pom.xml

@@ -47,6 +47,7 @@
         <includes>
           <include>google/protobuf/any.proto</include>
           <include>google/protobuf/api.proto</include>
+          <include>google/protobuf/descriptor.proto</include>
           <include>google/protobuf/duration.proto</include>
           <include>google/protobuf/empty.proto</include>
           <include>google/protobuf/field_mask.proto</include>
@@ -57,6 +58,12 @@
           <include>google/protobuf/wrappers.proto</include>
         </includes>
       </resource>
+      <resource>
+        <directory>${protobuf.java_source.dir}</directory>
+        <includes>
+          <include>main/java/com/google/protobuf/java_features.proto</include>
+        </includes>
+      </resource>
     </resources>
     <testResources>
       <testResource>

src/google/protobuf/compiler/command_line_interface.cc

@@ -2657,14 +2657,6 @@ bool CommandLineInterface::GenerateOutput(
       return false;
     }
 
-    // TODO: Remove once Java lite supports editions.
-    if (output_directive.name == "--java_out" && experimental_editions_) {
-      if (!parameters.empty()) {
-        parameters.append(",");
-      }
-      parameters.append("experimental_editions");
-    }
-
     if (!output_directive.generator->GenerateAll(parsed_files, parameters,
                                                  generator_context, &error)) {
       // Generator returned an error.

src/google/protobuf/compiler/java/generator.cc

@@ -55,7 +55,6 @@ bool JavaGenerator::Generate(const FileDescriptor* file,
 
   file_options.opensource_runtime = opensource_runtime_;
 
-  bool enforce_editions = true;
   for (auto& option : options) {
     if (option.first == "output_list_file") {
       file_options.output_list_file = option.second;
@@ -75,8 +74,6 @@ bool JavaGenerator::Generate(const FileDescriptor* file,
       file_options.annotation_list_file = option.second;
     } else if (option.first == "experimental_strip_nonfunctional_codegen") {
       file_options.strip_nonfunctional_codegen = true;
-    } else if (option.first == "experimental_editions") {
-      enforce_editions = false;
     } else {
       *error = absl::StrCat("Unknown generator option: ", option.first);
       return false;
@@ -88,14 +85,6 @@ bool JavaGenerator::Generate(const FileDescriptor* file,
     return false;
   }
 
-  // TODO: Remove once Java lite supports editions
-  if (enforce_editions && !CanSkipEditionCheck(file->name()) &&
-      file_options.enforce_lite &&
-      GetEdition(*file) > google::protobuf::Edition::EDITION_PROTO3) {
-    *error = "lite runtime generator option cannot be used with editions yet.";
-    return false;
-  }
-
   // By default we generate immutable code and shared code for immutable API.
   if (!file_options.generate_immutable_code &&
       !file_options.generate_mutable_code &&

src/google/protobuf/editions/BUILD

@@ -132,6 +132,13 @@ java_proto_library(
     deps = [":test_messages_proto2_editions_proto"],
 )
 
+java_lite_proto_library(
+    name = "test_messages_proto2_editions_java_proto_lite",
+    testonly = True,
+    visibility = ["//conformance:__pkg__"],
+    deps = [":test_messages_proto2_editions_proto"],
+)
+
 py_proto_library(
     name = "test_messages_proto2_editions_py_pb2",
     testonly = True,
@@ -193,6 +200,13 @@ java_proto_library(
     deps = [":test_messages_proto3_editions_proto"],
 )
 
+java_lite_proto_library(
+    name = "test_messages_proto3_editions_java_proto_lite",
+    testonly = True,
+    visibility = ["//conformance:__pkg__"],
+    deps = [":test_messages_proto3_editions_proto"],
+)
+
 py_proto_library(
     name = "test_messages_proto3_editions_py_pb2",
     testonly = True,

src/google/protobuf/map_lite_unittest.proto

@@ -5,12 +5,14 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-syntax = "proto2";
+edition = "2023";
 
 package protobuf_unittest;
 
 import "google/protobuf/unittest_lite.proto";
 
+option features.enum_type = CLOSED;
+option features.utf8_validation = NONE;
 option cc_enable_arenas = true;
 option optimize_for = LITE_RUNTIME;
 
@@ -94,15 +96,17 @@ enum MapEnumLite {
 }
 
 message TestRequiredLite {
-  required int32 a = 1;
-  required int32 b = 2;
-  required int32 c = 3;
+  int32 a = 1 [features.field_presence = LEGACY_REQUIRED];
+
+  int32 b = 2 [features.field_presence = LEGACY_REQUIRED];
+
+  int32 c = 3 [features.field_presence = LEGACY_REQUIRED];
 
   extend TestAllExtensionsLite {
-    optional TestRequiredLite single = 1000;
+    TestRequiredLite single = 1000;
   }
 }
 
 message ForeignMessageArenaLite {
-  optional int32 c = 1;
+  int32 c = 1;
 }

src/google/protobuf/unittest_import_lite.proto

@@ -9,7 +9,7 @@
 //
 // This is like unittest_import.proto but with optimize_for = LITE_RUNTIME.
 
-syntax = "proto2";
+edition = "2023";
 
 package protobuf_unittest_import;
 
@@ -19,10 +19,12 @@ option optimize_for = LITE_RUNTIME;
 option java_package = "com.google.protobuf";
 
 message ImportMessageLite {
-  optional int32 d = 1;
+  int32 d = 1;
 }
 
 enum ImportEnumLite {
+  option features.enum_type = CLOSED;
+
   IMPORT_LITE_FOO = 7;
   IMPORT_LITE_BAR = 8;
   IMPORT_LITE_BAZ = 9;

src/google/protobuf/unittest_import_public_lite.proto

@@ -7,7 +7,7 @@
 
 // Author: liujisi@google.com (Pherl Liu)
 
-syntax = "proto2";
+edition = "2023";
 
 package protobuf_unittest_import;
 
@@ -15,5 +15,5 @@ option optimize_for = LITE_RUNTIME;
 option java_package = "com.google.protobuf";
 
 message PublicImportMessageLite {
-  optional int32 e = 1;
+  int32 e = 1;
 }

src/google/protobuf/unittest_lite.proto

@@ -9,12 +9,15 @@
 //
 // This is like unittest.proto but with optimize_for = LITE_RUNTIME.
 
-syntax = "proto2";
+edition = "2023";
 
 package protobuf_unittest;
 
 import "google/protobuf/unittest_import_lite.proto";
 
+option features.enum_type = CLOSED;
+option features.repeated_field_encoding = EXPANDED;
+option features.utf8_validation = NONE;
 option cc_enable_arenas = true;
 option optimize_for = LITE_RUNTIME;
 option java_package = "com.google.protobuf";
@@ -22,13 +25,13 @@ option java_package = "com.google.protobuf";
 // Same as TestAllTypes but with the lite runtime.
 message TestAllTypesLite {
   message NestedMessage {
-    optional int32 bb = 1;
-    optional int64 cc = 2;
-    repeated int32 dd = 3 [packed = true];
+    int32 bb = 1;
+    int64 cc = 2;
+    repeated int32 dd = 3 [features.repeated_field_encoding = PACKED];
   }
 
   message NestedMessage2 {
-    optional int32 dd = 1;
+    int32 dd = 1;
   }
 
   enum NestedEnum {
@@ -38,45 +41,44 @@ message TestAllTypesLite {
   }
 
   // Singular
-  optional int32 optional_int32 = 1;
-  optional int64 optional_int64 = 2;
-  optional uint32 optional_uint32 = 3;
-  optional uint64 optional_uint64 = 4;
-  optional sint32 optional_sint32 = 5;
-  optional sint64 optional_sint64 = 6;
-  optional fixed32 optional_fixed32 = 7;
-  optional fixed64 optional_fixed64 = 8;
-  optional sfixed32 optional_sfixed32 = 9;
-  optional sfixed64 optional_sfixed64 = 10;
-  optional float optional_float = 11;
-  optional double optional_double = 12;
-  optional bool optional_bool = 13;
-  optional string optional_string = 14;
-  optional bytes optional_bytes = 15;
-
-  optional group OptionalGroup = 16 {
-    optional int32 a = 17;
+  int32 optional_int32 = 1;
+  int64 optional_int64 = 2;
+  uint32 optional_uint32 = 3;
+  uint64 optional_uint64 = 4;
+  sint32 optional_sint32 = 5;
+  sint64 optional_sint64 = 6;
+  fixed32 optional_fixed32 = 7;
+  fixed64 optional_fixed64 = 8;
+  sfixed32 optional_sfixed32 = 9;
+  sfixed64 optional_sfixed64 = 10;
+  float optional_float = 11;
+  double optional_double = 12;
+  bool optional_bool = 13;
+  string optional_string = 14;
+  bytes optional_bytes = 15;
+
+  message OptionalGroup {
+    int32 a = 17;
   }
 
-  optional NestedMessage optional_nested_message = 18;
-  optional ForeignMessageLite optional_foreign_message = 19;
-  optional protobuf_unittest_import.ImportMessageLite optional_import_message =
-      20;
+  OptionalGroup optionalgroup = 16 [features.message_encoding = DELIMITED];
 
-  optional NestedEnum optional_nested_enum = 21;
-  optional ForeignEnumLite optional_foreign_enum = 22;
-  optional protobuf_unittest_import.ImportEnumLite optional_import_enum = 23;
+  NestedMessage optional_nested_message = 18;
+  ForeignMessageLite optional_foreign_message = 19;
+  protobuf_unittest_import.ImportMessageLite optional_import_message = 20;
+  NestedEnum optional_nested_enum = 21;
+  ForeignEnumLite optional_foreign_enum = 22;
+  protobuf_unittest_import.ImportEnumLite optional_import_enum = 23;
+  string optional_string_piece = 24 [ctype = STRING_PIECE];
 
-  optional string optional_string_piece = 24 [ctype = STRING_PIECE];
-  optional string optional_cord = 25 [ctype = CORD];
+  string optional_cord = 25 [ctype = CORD];
 
   // Defined in unittest_import_public.proto
-  optional protobuf_unittest_import.PublicImportMessageLite
+  protobuf_unittest_import.PublicImportMessageLite
       optional_public_import_message = 26;
+  NestedMessage optional_lazy_message = 27 [lazy = true];
 
-  optional NestedMessage optional_lazy_message = 27 [lazy = true];
-  optional NestedMessage optional_unverified_lazy_message = 28
-      [unverified_lazy = true];
+  NestedMessage optional_unverified_lazy_message = 28 [unverified_lazy = true];
 
   // Repeated
   repeated int32 repeated_int32 = 31;
@@ -95,50 +97,67 @@ message TestAllTypesLite {
   repeated string repeated_string = 44;
   repeated bytes repeated_bytes = 45;
 
-  repeated group RepeatedGroup = 46 {
-    optional int32 a = 47;
+  message RepeatedGroup {
+    int32 a = 47;
   }
 
+  repeated RepeatedGroup repeatedgroup = 46
+      [features.message_encoding = DELIMITED];
+
   repeated NestedMessage repeated_nested_message = 48;
   repeated ForeignMessageLite repeated_foreign_message = 49;
   repeated protobuf_unittest_import.ImportMessageLite repeated_import_message =
       50;
-
   repeated NestedEnum repeated_nested_enum = 51;
   repeated ForeignEnumLite repeated_foreign_enum = 52;
   repeated protobuf_unittest_import.ImportEnumLite repeated_import_enum = 53;
-
   repeated string repeated_string_piece = 54 [ctype = STRING_PIECE];
+
   repeated string repeated_cord = 55 [ctype = CORD];
 
-  repeated NestedMessage repeated_lazy_message = 57 ;
+  repeated NestedMessage repeated_lazy_message = 57;
 
   // Singular with defaults
-  optional int32 default_int32 = 61 [default = 41];
-  optional int64 default_int64 = 62 [default = 42];
-  optional uint32 default_uint32 = 63 [default = 43];
-  optional uint64 default_uint64 = 64 [default = 44];
-  optional sint32 default_sint32 = 65 [default = -45];
-  optional sint64 default_sint64 = 66 [default = 46];
-  optional fixed32 default_fixed32 = 67 [default = 47];
-  optional fixed64 default_fixed64 = 68 [default = 48];
-  optional sfixed32 default_sfixed32 = 69 [default = 49];
-  optional sfixed64 default_sfixed64 = 70 [default = -50];
-  optional float default_float = 71 [default = 51.5];
-  optional double default_double = 72 [default = 52e3];
-  optional bool default_bool = 73 [default = true];
-  optional string default_string = 74 [default = "hello"];
-  optional bytes default_bytes = 75 [default = "world"];
-
-  optional NestedEnum default_nested_enum = 81 [default = BAR];
-  optional ForeignEnumLite default_foreign_enum = 82
-      [default = FOREIGN_LITE_BAR];
-  optional protobuf_unittest_import.ImportEnumLite default_import_enum = 83
+  int32 default_int32 = 61 [default = 41];
+
+  int64 default_int64 = 62 [default = 42];
+
+  uint32 default_uint32 = 63 [default = 43];
+
+  uint64 default_uint64 = 64 [default = 44];
+
+  sint32 default_sint32 = 65 [default = -45];
+
+  sint64 default_sint64 = 66 [default = 46];
+
+  fixed32 default_fixed32 = 67 [default = 47];
+
+  fixed64 default_fixed64 = 68 [default = 48];
+
+  sfixed32 default_sfixed32 = 69 [default = 49];
+
+  sfixed64 default_sfixed64 = 70 [default = -50];
+
+  float default_float = 71 [default = 51.5];
+
+  double default_double = 72 [default = 5.2e4];
+
+  bool default_bool = 73 [default = true];
+
+  string default_string = 74 [default = "hello"];
+
+  bytes default_bytes = 75 [default = "world"];
+
+  NestedEnum default_nested_enum = 81 [default = BAR];
+
+  ForeignEnumLite default_foreign_enum = 82 [default = FOREIGN_LITE_BAR];
+
+  protobuf_unittest_import.ImportEnumLite default_import_enum = 83
       [default = IMPORT_LITE_BAR];
 
-  optional string default_string_piece = 84
-      [ctype = STRING_PIECE, default = "abc"];
-  optional string default_cord = 85 [ctype = CORD, default = "123"];
+  string default_string_piece = 84 [ctype = STRING_PIECE, default = "abc"];
+
+  string default_cord = 85 [ctype = CORD, default = "123"];
 
   // For oneof test
   oneof oneof_field {
@@ -147,15 +166,16 @@ message TestAllTypesLite {
     string oneof_string = 113;
     bytes oneof_bytes = 114;
     NestedMessage oneof_lazy_nested_message = 115 [lazy = true];
+
     NestedMessage2 oneof_nested_message2 = 117;
   }
 
   // Tests toString for non-repeated fields with a list suffix
-  optional int32 deceptively_named_list = 116;
+  int32 deceptively_named_list = 116;
 }
 
 message ForeignMessageLite {
-  optional int32 c = 1;
+  int32 c = 1;
 }
 
 enum ForeignEnumLite {
@@ -165,20 +185,43 @@ enum ForeignEnumLite {
 }
 
 message TestPackedTypesLite {
-  repeated int32 packed_int32 = 90 [packed = true];
-  repeated int64 packed_int64 = 91 [packed = true];
-  repeated uint32 packed_uint32 = 92 [packed = true];
-  repeated uint64 packed_uint64 = 93 [packed = true];
-  repeated sint32 packed_sint32 = 94 [packed = true];
-  repeated sint64 packed_sint64 = 95 [packed = true];
-  repeated fixed32 packed_fixed32 = 96 [packed = true];
-  repeated fixed64 packed_fixed64 = 97 [packed = true];
-  repeated sfixed32 packed_sfixed32 = 98 [packed = true];
-  repeated sfixed64 packed_sfixed64 = 99 [packed = true];
-  repeated float packed_float = 100 [packed = true];
-  repeated double packed_double = 101 [packed = true];
-  repeated bool packed_bool = 102 [packed = true];
-  repeated ForeignEnumLite packed_enum = 103 [packed = true];
+  repeated int32 packed_int32 = 90 [features.repeated_field_encoding = PACKED];
+
+  repeated int64 packed_int64 = 91 [features.repeated_field_encoding = PACKED];
+
+  repeated uint32 packed_uint32 = 92
+      [features.repeated_field_encoding = PACKED];
+
+  repeated uint64 packed_uint64 = 93
+      [features.repeated_field_encoding = PACKED];
+
+  repeated sint32 packed_sint32 = 94
+      [features.repeated_field_encoding = PACKED];
+
+  repeated sint64 packed_sint64 = 95
+      [features.repeated_field_encoding = PACKED];
+
+  repeated fixed32 packed_fixed32 = 96
+      [features.repeated_field_encoding = PACKED];
+
+  repeated fixed64 packed_fixed64 = 97
+      [features.repeated_field_encoding = PACKED];
+
+  repeated sfixed32 packed_sfixed32 = 98
+      [features.repeated_field_encoding = PACKED];
+
+  repeated sfixed64 packed_sfixed64 = 99
+      [features.repeated_field_encoding = PACKED];
+
+  repeated float packed_float = 100 [features.repeated_field_encoding = PACKED];
+
+  repeated double packed_double = 101
+      [features.repeated_field_encoding = PACKED];
+
+  repeated bool packed_bool = 102 [features.repeated_field_encoding = PACKED];
+
+  repeated ForeignEnumLite packed_enum = 103
+      [features.repeated_field_encoding = PACKED];
 }
 
 message TestAllExtensionsLite {
@@ -187,49 +230,43 @@ message TestAllExtensionsLite {
 
 extend TestAllExtensionsLite {
   // Singular
-  optional int32 optional_int32_extension_lite = 1;
-  optional int64 optional_int64_extension_lite = 2;
-  optional uint32 optional_uint32_extension_lite = 3;
-  optional uint64 optional_uint64_extension_lite = 4;
-  optional sint32 optional_sint32_extension_lite = 5;
-  optional sint64 optional_sint64_extension_lite = 6;
-  optional fixed32 optional_fixed32_extension_lite = 7;
-  optional fixed64 optional_fixed64_extension_lite = 8;
-  optional sfixed32 optional_sfixed32_extension_lite = 9;
-  optional sfixed64 optional_sfixed64_extension_lite = 10;
-  optional float optional_float_extension_lite = 11;
-  optional double optional_double_extension_lite = 12;
-  optional bool optional_bool_extension_lite = 13;
-  optional string optional_string_extension_lite = 14;
-  optional bytes optional_bytes_extension_lite = 15;
-
-  optional group OptionalGroup_extension_lite = 16 {
-    optional int32 a = 17;
-  }
-
-  optional TestAllTypesLite.NestedMessage
-      optional_nested_message_extension_lite = 18;
-  optional ForeignMessageLite optional_foreign_message_extension_lite = 19;
-  optional protobuf_unittest_import.ImportMessageLite
+  int32 optional_int32_extension_lite = 1;
+  int64 optional_int64_extension_lite = 2;
+  uint32 optional_uint32_extension_lite = 3;
+  uint64 optional_uint64_extension_lite = 4;
+  sint32 optional_sint32_extension_lite = 5;
+  sint64 optional_sint64_extension_lite = 6;
+  fixed32 optional_fixed32_extension_lite = 7;
+  fixed64 optional_fixed64_extension_lite = 8;
+  sfixed32 optional_sfixed32_extension_lite = 9;
+  sfixed64 optional_sfixed64_extension_lite = 10;
+  float optional_float_extension_lite = 11;
+  double optional_double_extension_lite = 12;
+  bool optional_bool_extension_lite = 13;
+  string optional_string_extension_lite = 14;
+  bytes optional_bytes_extension_lite = 15;
+  OptionalGroup_extension_lite optionalgroup_extension_lite = 16
+      [features.message_encoding = DELIMITED];
+
+  TestAllTypesLite.NestedMessage optional_nested_message_extension_lite = 18;
+  ForeignMessageLite optional_foreign_message_extension_lite = 19;
+  protobuf_unittest_import.ImportMessageLite
       optional_import_message_extension_lite = 20;
+  TestAllTypesLite.NestedEnum optional_nested_enum_extension_lite = 21;
+  ForeignEnumLite optional_foreign_enum_extension_lite = 22;
+  protobuf_unittest_import.ImportEnumLite optional_import_enum_extension_lite =
+      23;
+  string optional_string_piece_extension_lite = 24 [ctype = STRING_PIECE];
 
-  optional TestAllTypesLite.NestedEnum optional_nested_enum_extension_lite = 21;
-  optional ForeignEnumLite optional_foreign_enum_extension_lite = 22;
-  optional protobuf_unittest_import.ImportEnumLite
-      optional_import_enum_extension_lite = 23;
-
-  optional string optional_string_piece_extension_lite = 24
-      [ctype = STRING_PIECE];
   // TODO: ctype=CORD is not supported for extension. Add
   // ctype=CORD option back after it is supported.
-  optional string optional_cord_extension_lite = 25;
-
-  optional protobuf_unittest_import.PublicImportMessageLite
+  string optional_cord_extension_lite = 25;
+  protobuf_unittest_import.PublicImportMessageLite
       optional_public_import_message_extension_lite = 26;
+  TestAllTypesLite.NestedMessage optional_lazy_message_extension_lite = 27
+      [lazy = true];
 
-  optional TestAllTypesLite.NestedMessage optional_lazy_message_extension_lite =
-      27 [lazy = true];
-  optional TestAllTypesLite.NestedMessage
+  TestAllTypesLite.NestedMessage
       optional_unverified_lazy_message_extension_lite = 28
       [unverified_lazy = true];
 
@@ -249,67 +286,87 @@ extend TestAllExtensionsLite {
   repeated bool repeated_bool_extension_lite = 43;
   repeated string repeated_string_extension_lite = 44;
   repeated bytes repeated_bytes_extension_lite = 45;
-
-  repeated group RepeatedGroup_extension_lite = 46 {
-    optional int32 a = 47;
-  }
+  repeated RepeatedGroup_extension_lite repeatedgroup_extension_lite = 46
+      [features.message_encoding = DELIMITED];
 
   repeated TestAllTypesLite.NestedMessage
       repeated_nested_message_extension_lite = 48;
   repeated ForeignMessageLite repeated_foreign_message_extension_lite = 49;
   repeated protobuf_unittest_import.ImportMessageLite
       repeated_import_message_extension_lite = 50;
-
   repeated TestAllTypesLite.NestedEnum repeated_nested_enum_extension_lite = 51;
   repeated ForeignEnumLite repeated_foreign_enum_extension_lite = 52;
   repeated protobuf_unittest_import.ImportEnumLite
       repeated_import_enum_extension_lite = 53;
-
   repeated string repeated_string_piece_extension_lite = 54
       [ctype = STRING_PIECE];
+
   // TODO: ctype=CORD is not supported for extension. Add
   // ctype=CORD option back after it is supported.
   repeated string repeated_cord_extension_lite = 55;
-
   repeated TestAllTypesLite.NestedMessage repeated_lazy_message_extension_lite =
       57 [lazy = true];
 
   // Singular with defaults
-  optional int32 default_int32_extension_lite = 61 [default = 41];
-  optional int64 default_int64_extension_lite = 62 [default = 42];
-  optional uint32 default_uint32_extension_lite = 63 [default = 43];
-  optional uint64 default_uint64_extension_lite = 64 [default = 44];
-  optional sint32 default_sint32_extension_lite = 65 [default = -45];
-  optional sint64 default_sint64_extension_lite = 66 [default = 46];
-  optional fixed32 default_fixed32_extension_lite = 67 [default = 47];
-  optional fixed64 default_fixed64_extension_lite = 68 [default = 48];
-  optional sfixed32 default_sfixed32_extension_lite = 69 [default = 49];
-  optional sfixed64 default_sfixed64_extension_lite = 70 [default = -50];
-  optional float default_float_extension_lite = 71 [default = 51.5];
-  optional double default_double_extension_lite = 72 [default = 52e3];
-  optional bool default_bool_extension_lite = 73 [default = true];
-  optional string default_string_extension_lite = 74 [default = "hello"];
-  optional bytes default_bytes_extension_lite = 75 [default = "world"];
-
-  optional TestAllTypesLite.NestedEnum default_nested_enum_extension_lite = 81
+  int32 default_int32_extension_lite = 61 [default = 41];
+
+  int64 default_int64_extension_lite = 62 [default = 42];
+
+  uint32 default_uint32_extension_lite = 63 [default = 43];
+
+  uint64 default_uint64_extension_lite = 64 [default = 44];
+
+  sint32 default_sint32_extension_lite = 65 [default = -45];
+
+  sint64 default_sint64_extension_lite = 66 [default = 46];
+
+  fixed32 default_fixed32_extension_lite = 67 [default = 47];
+
+  fixed64 default_fixed64_extension_lite = 68 [default = 48];
+
+  sfixed32 default_sfixed32_extension_lite = 69 [default = 49];
+
+  sfixed64 default_sfixed64_extension_lite = 70 [default = -50];
+
+  float default_float_extension_lite = 71 [default = 51.5];
+
+  double default_double_extension_lite = 72 [default = 5.2e4];
+
+  bool default_bool_extension_lite = 73 [default = true];
+
+  string default_string_extension_lite = 74 [default = "hello"];
+
+  bytes default_bytes_extension_lite = 75 [default = "world"];
+
+  TestAllTypesLite.NestedEnum default_nested_enum_extension_lite = 81
       [default = BAR];
-  optional ForeignEnumLite default_foreign_enum_extension_lite = 82
+
+  ForeignEnumLite default_foreign_enum_extension_lite = 82
       [default = FOREIGN_LITE_BAR];
-  optional protobuf_unittest_import.ImportEnumLite
-      default_import_enum_extension_lite = 83 [default = IMPORT_LITE_BAR];
 
-  optional string default_string_piece_extension_lite = 84
+  protobuf_unittest_import.ImportEnumLite default_import_enum_extension_lite = 83
+      [default = IMPORT_LITE_BAR];
+
+  string default_string_piece_extension_lite = 84
       [ctype = STRING_PIECE, default = "abc"];
+
   // TODO: ctype=CORD is not supported for extension. Add
   // ctype=CORD option back after it is supported.
-  optional string default_cord_extension_lite = 85 [default = "123"];
+  string default_cord_extension_lite = 85 [default = "123"];
 
   // For oneof test
-  optional uint32 oneof_uint32_extension_lite = 111;
-  optional TestAllTypesLite.NestedMessage oneof_nested_message_extension_lite =
-      112;
-  optional string oneof_string_extension_lite = 113;
-  optional bytes oneof_bytes_extension_lite = 114;
+  uint32 oneof_uint32_extension_lite = 111;
+  TestAllTypesLite.NestedMessage oneof_nested_message_extension_lite = 112;
+  string oneof_string_extension_lite = 113;
+  bytes oneof_bytes_extension_lite = 114;
+}
+
+message OptionalGroup_extension_lite {
+  int32 a = 17;
+}
+
+message RepeatedGroup_extension_lite {
+  int32 a = 47;
 }
 
 message TestPackedExtensionsLite {
@@ -317,35 +374,66 @@ message TestPackedExtensionsLite {
 }
 
 extend TestPackedExtensionsLite {
-  repeated int32 packed_int32_extension_lite = 90 [packed = true];
-  repeated int64 packed_int64_extension_lite = 91 [packed = true];
-  repeated uint32 packed_uint32_extension_lite = 92 [packed = true];
-  repeated uint64 packed_uint64_extension_lite = 93 [packed = true];
-  repeated sint32 packed_sint32_extension_lite = 94 [packed = true];
-  repeated sint64 packed_sint64_extension_lite = 95 [packed = true];
-  repeated fixed32 packed_fixed32_extension_lite = 96 [packed = true];
-  repeated fixed64 packed_fixed64_extension_lite = 97 [packed = true];
-  repeated sfixed32 packed_sfixed32_extension_lite = 98 [packed = true];
-  repeated sfixed64 packed_sfixed64_extension_lite = 99 [packed = true];
-  repeated float packed_float_extension_lite = 100 [packed = true];
-  repeated double packed_double_extension_lite = 101 [packed = true];
-  repeated bool packed_bool_extension_lite = 102 [packed = true];
-  repeated ForeignEnumLite packed_enum_extension_lite = 103 [packed = true];
+  repeated int32 packed_int32_extension_lite = 90
+      [features.repeated_field_encoding = PACKED];
+
+  repeated int64 packed_int64_extension_lite = 91
+      [features.repeated_field_encoding = PACKED];
+
+  repeated uint32 packed_uint32_extension_lite = 92
+      [features.repeated_field_encoding = PACKED];
+
+  repeated uint64 packed_uint64_extension_lite = 93
+      [features.repeated_field_encoding = PACKED];
+
+  repeated sint32 packed_sint32_extension_lite = 94
+      [features.repeated_field_encoding = PACKED];
+
+  repeated sint64 packed_sint64_extension_lite = 95
+      [features.repeated_field_encoding = PACKED];
+
+  repeated fixed32 packed_fixed32_extension_lite = 96
+      [features.repeated_field_encoding = PACKED];
+
+  repeated fixed64 packed_fixed64_extension_lite = 97
+      [features.repeated_field_encoding = PACKED];
+
+  repeated sfixed32 packed_sfixed32_extension_lite = 98
+      [features.repeated_field_encoding = PACKED];
+
+  repeated sfixed64 packed_sfixed64_extension_lite = 99
+      [features.repeated_field_encoding = PACKED];
+
+  repeated float packed_float_extension_lite = 100
+      [features.repeated_field_encoding = PACKED];
+
+  repeated double packed_double_extension_lite = 101
+      [features.repeated_field_encoding = PACKED];
+
+  repeated bool packed_bool_extension_lite = 102
+      [features.repeated_field_encoding = PACKED];
+
+  repeated ForeignEnumLite packed_enum_extension_lite = 103
+      [features.repeated_field_encoding = PACKED];
 }
 
 message TestNestedExtensionLite {
   extend TestAllExtensionsLite {
-    optional int32 nested_extension = 12345;
+    int32 nested_extension = 12345;
   }
 }
 
 // Test that deprecated fields work.  We only verify that they compile (at one
 // point this failed).
 message TestDeprecatedLite {
-  optional int32 deprecated_field = 1 [deprecated = true];
-  required int32 deprecated_field2 = 2 [deprecated = true];
-  optional string deprecated_field3 = 3 [deprecated = true];
-  optional TestDeprecatedLite deprecated_field4 = 4 [deprecated = true];
+  int32 deprecated_field = 1 [deprecated = true];
+
+  int32 deprecated_field2 = 2
+      [features.field_presence = LEGACY_REQUIRED, deprecated = true];
+
+  string deprecated_field3 = 3 [deprecated = true];
+
+  TestDeprecatedLite deprecated_field4 = 4 [deprecated = true];
 }
 
 // See the comments of the same type in unittest.proto.
@@ -354,27 +442,46 @@ message TestParsingMergeLite {
     repeated TestAllTypesLite field1 = 1;
     repeated TestAllTypesLite field2 = 2;
     repeated TestAllTypesLite field3 = 3;
-    repeated group Group1 = 10 {
-      optional TestAllTypesLite field1 = 11;
+
+    message Group1 {
+      TestAllTypesLite field1 = 11;
     }
-    repeated group Group2 = 20 {
-      optional TestAllTypesLite field1 = 21;
+
+    repeated Group1 group1 = 10 [features.message_encoding = DELIMITED];
+
+    message Group2 {
+      TestAllTypesLite field1 = 21;
     }
+
+    repeated Group2 group2 = 20 [features.message_encoding = DELIMITED];
+
     repeated TestAllTypesLite ext1 = 1000;
     repeated TestAllTypesLite ext2 = 1001;
   }
-  required TestAllTypesLite required_all_types = 1;
-  optional TestAllTypesLite optional_all_types = 2;
+
+  TestAllTypesLite required_all_types = 1
+      [features.field_presence = LEGACY_REQUIRED];
+
+  TestAllTypesLite optional_all_types = 2;
   repeated TestAllTypesLite repeated_all_types = 3;
-  optional group OptionalGroup = 10 {
-    optional TestAllTypesLite optional_group_all_types = 11;
+
+  message OptionalGroup {
+    TestAllTypesLite optional_group_all_types = 11;
   }
-  repeated group RepeatedGroup = 20 {
-    optional TestAllTypesLite repeated_group_all_types = 21;
+
+  OptionalGroup optionalgroup = 10 [features.message_encoding = DELIMITED];
+
+  message RepeatedGroup {
+    TestAllTypesLite repeated_group_all_types = 21;
   }
+
+  repeated RepeatedGroup repeatedgroup = 20
+      [features.message_encoding = DELIMITED];
+
   extensions 1000 to max;
+
   extend TestParsingMergeLite {
-    optional TestAllTypesLite optional_ext = 1000;
+    TestAllTypesLite optional_ext = 1000;
     repeated TestAllTypesLite repeated_ext = 1001;
   }
 }
@@ -382,7 +489,7 @@ message TestParsingMergeLite {
 // Test that the correct exception is thrown by parseFrom in a corner case
 // involving merging, extensions, and required fields.
 message TestMergeExceptionLite {
-  optional TestAllExtensionsLite all_extensions = 1;
+  TestAllExtensionsLite all_extensions = 1;
 }
 
 // TestEmptyMessageLite is used to test unknown fields support in lite mode.
@@ -404,30 +511,36 @@ enum V2EnumLite {
 }
 
 message V1MessageLite {
-  required int32 int_field = 1;
-  optional V1EnumLite enum_field = 2 [default = V1_FIRST];
+  int32 int_field = 1 [features.field_presence = LEGACY_REQUIRED];
+
+  V1EnumLite enum_field = 2 [default = V1_FIRST];
 }
 
 message V2MessageLite {
-  required int32 int_field = 1;
-  optional V2EnumLite enum_field = 2 [default = V2_FIRST];
+  int32 int_field = 1 [features.field_presence = LEGACY_REQUIRED];
+
+  V2EnumLite enum_field = 2 [default = V2_FIRST];
 }
 
 message TestHugeFieldNumbersLite {
-  optional int32 optional_int32 = 536870000;
-  optional int32 fixed_32 = 536870001;
-  repeated int32 repeated_int32 = 536870002 [packed = false];
-  repeated int32 packed_int32 = 536870003 [packed = true];
-
-  optional ForeignEnumLite optional_enum = 536870004;
-  optional string optional_string = 536870005;
-  optional bytes optional_bytes = 536870006;
-  optional ForeignMessageLite optional_message = 536870007;
-
-  optional group OptionalGroup = 536870008 {
-    optional int32 group_a = 536870009;
+  int32 optional_int32 = 536870000;
+  int32 fixed_32 = 536870001;
+  repeated int32 repeated_int32 = 536870002;
+  repeated int32 packed_int32 = 536870003
+      [features.repeated_field_encoding = PACKED];
+
+  ForeignEnumLite optional_enum = 536870004;
+  string optional_string = 536870005;
+  bytes optional_bytes = 536870006;
+  ForeignMessageLite optional_message = 536870007;
+
+  message OptionalGroup {
+    int32 group_a = 536870009;
   }
 
+  OptionalGroup optionalgroup = 536870008
+      [features.message_encoding = DELIMITED];
+
   map<string, string> string_string_map = 536870010;
 
   oneof oneof_field {
@@ -445,7 +558,7 @@ message TestHugeFieldNumbersLite {
 }
 
 extend TestHugeFieldNumbersLite {
-  optional TestAllTypesLite test_all_types_lite = 536860000;
+  TestAllTypesLite test_all_types_lite = 536860000;
 }
 
 message TestOneofParsingLite {
@@ -454,11 +567,16 @@ message TestOneofParsingLite {
     TestAllTypesLite oneof_submessage = 2;
     string oneof_string = 3;
     bytes oneof_bytes = 4 [default = "default bytes"];
+
     string oneof_string_cord = 5 [ctype = CORD, default = "default Cord"];
+
     bytes oneof_bytes_cord = 6 [ctype = CORD];
+
     string oneof_string_string_piece = 7 [ctype = STRING_PIECE];
+
     bytes oneof_bytes_string_piece = 8
         [ctype = STRING_PIECE, default = "default StringPiece"];
+
     V2EnumLite oneof_enum = 9;
   }
 }
@@ -473,7 +591,8 @@ message TestMessageSetLite {
 // packed and non-packed repeated fields. We use the field number 2048, because
 // that is large enough to require a 3-byte varint for the tag.
 message PackedInt32 {
-  repeated int32 repeated_int32 = 2048 [packed = true];
+  repeated int32 repeated_int32 = 2048
+      [features.repeated_field_encoding = PACKED];
 }
 
 message NonPackedInt32 {
@@ -481,7 +600,8 @@ message NonPackedInt32 {
 }
 
 message PackedFixed32 {
-  repeated fixed32 repeated_fixed32 = 2048 [packed = true];
+  repeated fixed32 repeated_fixed32 = 2048
+      [features.repeated_field_encoding = PACKED];
 }
 
 message NonPackedFixed32 {
@@ -502,6 +622,6 @@ message DupEnum {
 }
 
 message RecursiveMessage {
-  optional RecursiveMessage recurse = 1;
-  optional bytes payload = 2;
+  RecursiveMessage recurse = 1;
+  bytes payload = 2;
 }