Breaking change: Lock down visibility for descriptor syntax APIs.

Users should migrate to corresponding feature accessors (e.g. FieldDescriptor.hasPresence, EnumDescriptor.isClosed) instead of deriving these based on syntax, which will break after under Editions (https://protobuf.dev/editions/overview/)

PiperOrigin-RevId: 586518687

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

@@ -140,8 +140,6 @@ public final class Descriptors {
     }
 
     /** The syntax of the .proto file. */
-    @Deprecated
-    public
     enum Syntax {
       UNKNOWN("unknown"),
       PROTO2("proto2"),
@@ -156,8 +154,6 @@ public final class Descriptors {
     }
 
     /** Get the syntax of the .proto file. */
-    @Deprecated
-    public
     Syntax getSyntax() {
       if (Syntax.PROTO3.name.equals(proto.getSyntax())) {
         return Syntax.PROTO3;
@@ -1273,8 +1269,6 @@ public final class Descriptors {
      * Returns true if this field was syntactically written with "optional" in the .proto file.
      * Excludes singular proto3 fields that do not have a label.
      */
-    @Deprecated
-    public
     boolean hasOptionalKeyword() {
       return isProto3Optional
           || (file.getSyntax() == Syntax.PROTO2 && isOptional() && getContainingOneof() == null);
@@ -2843,8 +2837,6 @@ public final class Descriptors {
       return proto;
     }
 
-    @Deprecated
-    public
     boolean isSynthetic() {
       return fields.length == 1 && fields[0].isProto3Optional;
     }

ruby/src/main/java/com/google/protobuf/jruby/RubyMessage.java

@@ -42,6 +42,7 @@ import com.google.protobuf.Descriptors.OneofDescriptor;
 import com.google.protobuf.DynamicMessage;
 import com.google.protobuf.InvalidProtocolBufferException;
 import com.google.protobuf.LegacyDescriptorsUtil.LegacyFileDescriptor;
+import com.google.protobuf.LegacyDescriptorsUtil.LegacyOneofDescriptor;
 import com.google.protobuf.Message;
 import com.google.protobuf.UnknownFieldSet;
 import com.google.protobuf.util.JsonFormat;
@@ -1340,7 +1341,7 @@ public class RubyMessage extends RubyObject {
         // Keep track of what Oneofs are set
         if (value.isNil()) {
           oneofCases.remove(oneofDescriptor);
-          if (!oneofDescriptor.isSynthetic()) {
+          if (!LegacyOneofDescriptor.isSynthetic(oneofDescriptor)) {
             addValue = false;
           }
         } else {