For Ruby oneof fields, generate hazzers for members (#11655)

When generating Ruby clients for proto3 messages that have a oneof, we generate a hazzer for members of the oneof, not just a hazzer for the oneof itself.

In other words, for a proto like this:

```
syntax = "proto3";
message Foo {
  oneof bar {
    string baz = 1;
  }
}
```

The generated `Foo` will now have a method called `has_baz?`, in addition to the (pre-existing) method `has_bar?`.

I updated the unit tests, and verified that all the tests under `//ruby/...` pass.

Fixes https://github.com/protocolbuffers/protobuf/issues/9561.

Closes #11655

COPYBARA_INTEGRATE_REVIEW=https://github.com/protocolbuffers/protobuf/pull/11655 from shaldengeki:test-ruby-oneof-hazzer a15e474da6
PiperOrigin-RevId: 506090930

ruby/ext/google/protobuf_c/message.c

@@ -243,15 +243,6 @@ static int extract_method_call(VALUE method_name, Message* self,
   if (Match(m, name, f, o, "clear_", "")) return METHOD_CLEAR;
   if (Match(m, name, f, o, "has_", "?") &&
       (*o || (*f && upb_FieldDef_HasPresence(*f)))) {
-    // Disallow oneof hazzers for proto3.
-    // TODO(haberman): remove this test when we are enabling oneof hazzers for
-    // proto3.
-    if (*f && !upb_FieldDef_IsSubMessage(*f) &&
-        upb_FieldDef_RealContainingOneof(*f) &&
-        upb_MessageDef_Syntax(upb_FieldDef_ContainingType(*f)) !=
-            kUpb_Syntax_Proto2) {
-      return METHOD_UNKNOWN;
-    }
     return METHOD_PRESENCE;
   }
   if (Match(m, name, f, o, "", "_as_value") && *f &&
@@ -1287,12 +1278,12 @@ VALUE build_module_from_enumdesc(VALUE _enumdesc) {
     int32_t value = upb_EnumValueDef_Number(ev);
     if (name[0] < 'A' || name[0] > 'Z') {
       if (name[0] >= 'a' && name[0] <= 'z') {
-        name[0] -= 32; // auto capitalize
+        name[0] -= 32;  // auto capitalize
       } else {
         rb_warn(
-          "Enum value '%s' does not start with an uppercase letter "
-          "as is required for Ruby constants.",
-          name);
+            "Enum value '%s' does not start with an uppercase letter "
+            "as is required for Ruby constants.",
+            name);
       }
     }
     rb_define_const(mod, name, INT2NUM(value));

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

@@ -306,11 +306,7 @@ public class RubyMessage extends RubyObject {
     if (methodName.startsWith(HAS_PREFIX) && methodName.endsWith(QUESTION_MARK)) {
       String strippedMethodName = methodName.substring(4, methodName.length() - 1);
       FieldDescriptor fieldDescriptor = descriptor.findFieldByName(strippedMethodName);
-      if (fieldDescriptor != null
-          && (!proto3
-              || fieldDescriptor.getContainingOneof() == null
-              || fieldDescriptor.getContainingOneof().isSynthetic())
-          && fieldDescriptor.hasPresence()) {
+      if (fieldDescriptor != null && fieldDescriptor.hasPresence()) {
         return context.runtime.getTrue();
       }
       oneofDescriptor =
@@ -459,11 +455,7 @@ public class RubyMessage extends RubyObject {
 
         fieldDescriptor = descriptor.findFieldByName(methodName);
 
-        if (fieldDescriptor != null
-            && (!proto3
-                || fieldDescriptor.getContainingOneof() == null
-                || fieldDescriptor.getContainingOneof().isSynthetic())
-            && fieldDescriptor.hasPresence()) {
+        if (fieldDescriptor != null && fieldDescriptor.hasPresence()) {
           return fields.containsKey(fieldDescriptor) ? runtime.getTrue() : runtime.getFalse();
         }
 

ruby/tests/basic.rb

@@ -119,11 +119,10 @@ module BasicTest
 
       m = OneofMessage.new
       assert !m.has_my_oneof?
+      assert !m.has_a?
       m.a = "foo"
       assert m.has_my_oneof?
-      assert_raise NoMethodError do
-        m.has_a?
-      end
+      assert m.has_a?
       assert_true OneofMessage.descriptor.lookup('a').has?(m)
 
       m = TestSingularFields.new
@@ -716,24 +715,16 @@ module BasicTest
 
   def test_oneof_fields_respond_to? # regression test for issue 9202
     msg = proto_module::OneofMessage.new
-    # `has_` prefix + "?" suffix actions should only work for oneofs fields.
+    # `has_` prefix + "?" suffix actions should work for oneofs fields and members.
     assert msg.has_my_oneof?
     assert msg.respond_to? :has_my_oneof?
-    assert !msg.respond_to?( :has_a? )
-    assert_raise NoMethodError do
-      msg.has_a?
-    end
-    assert !msg.respond_to?( :has_b? )
-    assert_raise NoMethodError do
-      msg.has_b?
-    end
-    assert !msg.respond_to?( :has_c? )
-    assert_raise NoMethodError do
-      msg.has_c?
-    end
-    assert !msg.respond_to?( :has_d? )
-    assert_raise NoMethodError do
-      msg.has_d?
-    end
+    assert msg.respond_to?( :has_a? )
+    assert !msg.has_a?
+    assert msg.respond_to?( :has_b? )
+    assert !msg.has_b?
+    assert msg.respond_to?( :has_c? )
+    assert !msg.has_c?
+    assert msg.respond_to?( :has_d? )
+    assert !msg.has_d?
   end
 end