Fix M2M rollback: prevent bad rewriting of history_m2m

1 files changed, 12 insertions, 8 deletions

diff --git a/ishtar_common/utils.py b/ishtar_common/utils.py
index e293562ff..ba77a07e4 100644
--- a/ishtar_common/utils.py
+++ b/ishtar_common/utils.py
@@ -943,13 +943,17 @@ def m2m_historization_changed(sender, **kwargs):
                 continue
             values.append(value.history_compress())
         hist_values[attr] = values
-    # force resave of last history record
-    if hasattr(obj, 'skip_history_when_saving'):
-        delattr(obj, 'skip_history_when_saving')
     obj.history_m2m = hist_values
-    obj._force_history = True
-    q = obj.history.order_by("-history_date")
-    if q.count():
-        last = q.all()[0]
-        last.delete()
+    if getattr(obj, 'skip_history_when_saving', False):
+        # assume the last modifier is good...
+        q = obj.history.filter(
+            history_modifier_id=obj.history_modifier_id,
+        ).order_by('-history_date', '-history_id')
+        hist = q.all()[0]
+        hist.history_m2m = hist_values
+        hist.history_date = hist.last_modified = datetime.datetime.now()
+        hist.save()
+        obj.skip_history_when_saving = True
+    elif not obj.history_modifier:
+        obj.skip_history_when_saving = True
     obj.save()