Oneof field should be serialized even it's equal to default. (#3153)

1 files changed, 7 insertions, 0 deletions

diff --git a/php/src/Google/Protobuf/Internal/Message.php b/php/src/Google/Protobuf/Internal/Message.php
index cd15e0f0..10c639ac 100644
--- a/php/src/Google/Protobuf/Internal/Message.php
+++ b/php/src/Google/Protobuf/Internal/Message.php
@@ -739,6 +739,13 @@ class Message
      */
     private function existField($field)
     {
+        $oneof_index = $field->getOneofIndex();
+        if ($oneof_index !== -1) {
+            $oneof = $this->desc->getOneofDecl()[$oneof_index];
+            $oneof_name = $oneof->getName();
+            return $this->$oneof_name->getNumber() === $field->getNumber();
+        }
+
         $getter = $field->getGetter();
         $value = $this->$getter();
         return $value !== $this->defaultValue($field);