id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
7204	QuerySet cloning can sometimes fail	Dorian Grey <imgrey@…>	nobody	"[Original bug report removed; see [http://code.djangoproject.com/ticket/7204#comment:2 the second comment] for the original report. --JKM]

Under some circumstances -- often involving {{{select_related()}}} and {{{count()}}} -- {{{QuerySet.clone()}}} can cause exceptions related to deepcopy(). These exceptions look like

{{{
TypeError: instancemethod expected at least 2 arguments, got 0
}}}
or
{{{
TypeError: function expected at least 2 arguments, got 0
}}}

The first one involving {{{instancemethod}}} is probably related to a Python issue: see http://bugs.python.org/issue1515. 

The second involving {{{function}}} only seems to occur on Python 2.4 (and not 2.5), but since 1515 isn't fixed yet, it may be a seperate problem.

In either case, though, the root problem is that for some reason QuerySet is trying to clone instancemethods and unbound functions, which isn't exactly supported -- dunno what a copy of a function would do anyway. The likely fix will involve finding out where and why functions/methods are being coppied, and stop doing that."		reopened	Core (Other)	dev			qsrf-cleanup revision 7520		Accepted	0	0	0	0	0	0