Make actual assignment of assignable column overridable

In doing so, allow for the override function to raise a ValidationError
on an individual object, in which case this object is not updated and
the error is shown to the user, but other objects are still processed.

2 files changed, 19 insertions, 12 deletions

diff --git a/postgresqleu/util/backendforms.py b/postgresqleu/util/backendforms.py
index 8af4ea28..c796b145 100644
--- a/postgresqleu/util/backendforms.py
+++ b/postgresqleu/util/backendforms.py
@@ -172,6 +172,10 @@ class BackendForm(ConcurrentProtectedModelForm):
     def get_assignable_columns(cls, conference):
         return {}
 
+    @classmethod
+    def assign_assignable_column(cls, obj, what, setval):
+        setattr(obj, what, setval)
+
     def pre_create_item(self):
         pass
 
diff --git a/postgresqleu/util/backendviews.py b/postgresqleu/util/backendviews.py
index 94a273c4..8be4d1cc 100644
--- a/postgresqleu/util/backendviews.py
+++ b/postgresqleu/util/backendviews.py
@@ -280,19 +280,22 @@ def backend_list_editor(request, urlname, formclass, resturl, allow_new=True, al
 
                 with transaction.atomic():
                     for obj in objects.filter(id__in=request.POST.get('idlist').split(',')):
-                        if isinstance(getattr(obj, what), bool):
-                            # Special-case booleans, they can only be set to true or false, and clearfing
-                            # means the same as set to false.
-                            if setval:
-                                setattr(obj, what, True)
+                        try:
+                            if isinstance(getattr(obj, what), bool):
+                                # Special-case booleans, they can only be set to true or false, and clearfing
+                                # means the same as set to false.
+                                if setval:
+                                    formclass.assign_assignable_column(obj, what, True)
+                                else:
+                                    formclass.assign_assignable_column(obj, what, False)
                             else:
-                                setattr(obj, what, False)
-                        else:
-                            if setval is not None:
-                                setattr(obj, what, setval)
-                            else:
-                                setattr(obj, what, None)
-                        obj.save()
+                                if setval is not None:
+                                    formclass.assign_assignable_column(obj, what, setval)
+                                else:
+                                    formclass.assign_assignable_column(obj, what, None)
+                            obj.save()
+                        except ValidationError as e:
+                            messages.warning(request, 'Could not update "{}": {}'.format(obj, e.message))
                 return HttpResponseRedirect('.')
             else:
                 raise Http404()