From 782666bcafe94108a3f4950ae3510326edc77b6c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Laura=20Kl=C3=BCnder?= <laura@codingcatgirl.de>
Date: Mon, 10 Jul 2017 16:01:00 +0200
Subject: [PATCH] fix clean_m2m

---
 src/c3nav/editor/models/changeset.py | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/c3nav/editor/models/changeset.py b/src/c3nav/editor/models/changeset.py
index f8721e65..f7964f5a 100644
--- a/src/c3nav/editor/models/changeset.py
+++ b/src/c3nav/editor/models/changeset.py
@@ -171,8 +171,12 @@ class ChangeSet(models.Model):
         for change in self.changed_objects_set.all():
             change.update_changeset_cache()
 
-        if self.state != 'applied':
-            self._clean_changes()
+        if self.state != 'applied' and not self._cleaning_changes:
+            self._cleaning_changes = True
+            try:
+                self._clean_changes()
+            finally:
+                self._cleaning_changes = False
 
         cache.set(cache_key, (self.changed_objects, self.created_objects, self.updated_existing,
                               self.deleted_existing, self.m2m_added, self.m2m_removed), 300)
@@ -415,6 +419,16 @@ class ChangeSet(models.Model):
     def _object_changed(self, value):
         self.object_changed_cache[self.pk] = value
 
+    cleaning_changes_cache = {}
+
+    @property
+    def _cleaning_changes(self):
+        return self.cleaning_changes_cache.get(self.pk, None)
+
+    @_cleaning_changes.setter
+    def _cleaning_changes(self, value):
+        self.cleaning_changes_cache[self.pk] = value
+
     @contextmanager
     def lock_to_edit(self, request=None):
         with transaction.atomic():