Fixing encode#6053: injection of read-only default values is done too…

… late

rest_framework/serializers.py

@@ -431,7 +431,9 @@ def run_validation(self, data=empty):
         if is_empty_value:
             return data
 
-        value = self.to_internal_value(data)
+        to_validate = self._read_only_defaults()
+        to_validate.update(data)
+        value = self.to_internal_value(to_validate)
         try:
             self.run_validators(value)
             value = self.validate(value)
@@ -457,14 +459,6 @@ def _read_only_defaults(self):
 
         return defaults
 
-    def run_validators(self, value):
-        """
-        Add read_only fields with defaults to value before running validators.
-        """
-        to_validate = self._read_only_defaults()
-        to_validate.update(value)
-        super(Serializer, self).run_validators(to_validate)
-
     def to_internal_value(self, data):
         """
         Dict of native values <- Dict of primitive datatypes.