Merge ecf8c6f6ff into 6d4d4dfd04

rest_framework/relations.py

@@ -501,11 +501,20 @@ class ManyRelatedField(Field):
         if not self.allow_empty and len(data) == 0:
             self.fail('empty')
 
-        return [
+        if isinstance(self.child_relation, PrimaryKeyRelatedField):
+            values = list(self.child_relation.get_queryset().filter(pk__in=data))
+            missing_primary_keys = set(v.pk for v in values) - set(data)
+
+            if missing_primary_keys:
+                self.fail('missing_ids', ids_not_found=list(missing_primary_keys))
+        else:
+            values = [
                 self.child_relation.to_internal_value(item)
                 for item in data
             ]
 
+        return values
+
     def get_attribute(self, instance):
         # Can't have any relationships if not created
         if hasattr(instance, 'pk') and instance.pk is None: