Ticket #2579: fix_raw_id_admin_m2m.2.patch

django/db/models/manipulators.py

@@ -116 +116 @@
         for f in self.opts.many_to_many:
             if self.follow.get(f.name, None):
                 if not f.rel.edit_inline:
+
+                    # First, clear the existing values.
+                    rel_manager = getattr(new_object, f.name)
+                    rel_manager.clear()
+
                     if f.rel.raw_id_admin:
                         new_vals = new_data.get(f.name, ())
+                        # Not handling 'empty' raw_id_admin fields properly
+                        # If nothing was entered, skip the rel manager add 
+                        if len(new_vals) == 1 and '' == new_vals[0]:
+                            continue
                     else:
                         new_vals = new_data.getlist(f.name)
-                    # First, clear the existing values.
-                    rel_manager = getattr(new_object, f.name)
-                    rel_manager.clear()
                     # Then, set the new values.
                     for n in new_vals:
                         rel_manager.add(f.rel.to._default_manager.get(pk=n))