django-nonrel/django-dbindexer — pull request #6 by wrwrwr (2011-12-14 20:23:50+00:00)
Title: Make indexing work with nullable CharFields.

Dbindexer stores transformed values to simulate different filtering predicates using just "startswith" that is available on GAE (the filtering is actually done using two inequalities: "column >= prefix and column < (prefix + u'\ufffd')"). The value transformations (converting to lower case, reversing) do not check if the value is not None. It's seems like a good idea to add a check for all transformation functions (and let None values pass untransformed generally) rather than modify code of each affected predicate separately.

Patch by Wilfred Hughes.