Geometry race condition fix

* fixes race condition for geometry conflict and parcel calculation
* harmonizes empty geometries from None/MultiPolygonEmpty to MultiPolygonEmpty

intervention/forms/intervention.py

@@ -263,9 +263,6 @@ class NewInterventionForm(BaseForm):
                 handler=handler,
             )
 
-            # Process the geometry form
-            geometry = geom_form.save(action)
-
             # Finally create main object, holding the other objects
             intervention = Intervention.objects.create(
                 identifier=identifier,
@@ -273,7 +270,6 @@ class NewInterventionForm(BaseForm):
                 responsible=responsibility_data,
                 legal=legal_data,
                 created=action,
-                geometry=geometry,
                 comment=comment,
             )
 
@@ -282,6 +278,12 @@ class NewInterventionForm(BaseForm):
 
             # Add the performing user as the first user having access to the data
             intervention.share_with_user(user)
+
+        # Process the geometry form (NOT ATOMIC TRANSACTION DUE TO CELERY!)
+        geometry = geom_form.save(action)
+        intervention.geometry = geometry
+        intervention.save()
+
         return intervention
 
 
@@ -370,9 +372,6 @@ class EditInterventionForm(NewInterventionForm):
 
             user_action = self.instance.mark_as_edited(user, edit_comment=EDITED_GENERAL_DATA)
 
-            geometry = geom_form.save(user_action)
-            self.instance.geometry = geometry
-
             self.instance.log.add(user_action)
 
             self.instance.identifier = identifier
@@ -381,5 +380,10 @@ class EditInterventionForm(NewInterventionForm):
             self.instance.modified = user_action
             self.instance.save()
 
+        # Process the geometry form (NOT ATOMIC TRANSACTION DUE TO CELERY!)
+        geometry = geom_form.save(user_action)
+        self.instance.geometry = geometry
+        self.instance.save()
+
         return self.instance