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
29121	Admin ChangeList trims off multi-valued query parameters	Jeffrey Bian	nobody	"In contrib.admin.views.main module - ChangeList class constructor, when populating self.params with GET query parameters, it converts it into a single valued dict.
E.g., for customized parameters like ""tag=1&tag=10&tag=3"", only one value will be preserved.

https://github.com/django/django/blob/master/django/contrib/admin/views/main.py#L66

Suggested fix: 

Instead of calling request.GET.items(), usse request.GET.lists() so to preserve all values. Thus the line reads:


{{{
self.params = dict(request.GET.lists())
}}}


This will flatten the dict while making the multiple values of a key into a list. 

Patch below in attachment.

Regards,

"	Bug	closed	contrib.admin	dev	Normal	invalid	custom ChangeList admin		Unreviewed	1	0	0	0	1	0