MessageOneofRules proposal

Author: bufdev

proto/protovalidate/buf/validate/validate.proto

@@ -137,6 +137,16 @@ message MessageRules {
   // }
   // ```
   repeated Rule cel = 3;
+
+  // message MyMessage {
+  //   option (buf.validate.message).oneof = { fields: "field1", "field2" };
+  //   option (buf.validate.message).oneof = { fields: "field3", "field4" };
+  // }
+  repeated MessageOneofRule oneof = 4;
+}
+
+message MessageOneofRule {
+  repeated string fields = 1;
 }
 
 // The `OneofRules` message type enables you to manage rules for