4 commits

Author	SHA1	Message	Date
François Freitag	3fca95e1ad	Fixed #28312 -- Made ModelChoiceIterator.__len__() more memory-efficient. ... Instead of loading all QuerySet results in memory, count the number of entries. This adds an extra query when list() or tuple() is called on the choices (because both call __len__() then __iter__()) but uses less memory since the QuerySet results won't be cached. In most cases, the choices will only be iterated on, meaning that __len__() won't be called and only one query will be executed.	2018-04-23 12:39:43 -04:00
François Freitag	a2e97abd81	Fixed #29159 -- Made ModelChoiceIterator reuse QuerySet result cache. ... When __len__() is called (e.g. when casting to list or tuple), the QuerySet is evaluated and the result cache populated. iterator() shouldn't be called on the QuerySet after that, as it would reset the result cache and trigger a second query.	2018-03-01 14:17:56 -05:00
François Freitag	40f0aa9885	Fixed #29158 -- Fixed len(choices) crash if ModelChoiceField's queryset is a manager. ... Removing all() in __iter__() prevents a duplicate query when choices are cast to a list and there's a prefetch_related().	2018-03-01 14:12:14 -05:00
François Freitag	06172d7bc2	Consolidated ModelChoiceField tests.	2018-03-01 14:05:35 -05:00