partial argument should override required

rest_framework/fields.py

@@ -53,6 +53,8 @@ class Field(object):
         self.parent = parent
         self.root = parent.root or parent
         self.context = self.root.context
+        if self.root.partial:
+            self.required = False 
 
     def field_from_native(self, data, files, field_name, into):
         """
@@ -148,7 +150,7 @@ class WritableField(Field):
         self.widget = widget
 
     def validate(self, value):
-        if value in validators.EMPTY_VALUES and self.required and not self.root.partial:
+        if value in validators.EMPTY_VALUES and self.required:
             raise ValidationError(self.error_messages['required'])
 
     def run_validators(self, value):
@@ -186,7 +188,7 @@ class WritableField(Field):
             if self.default is not None:
                 native = self.default
             else:
-                if self.required and not self.root.partial:
+                if self.required:
                     raise ValidationError(self.error_messages['required'])
                 return