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
37340	admin.add_preserved_filters() drops repeated query parameters	ollehu	ollehu	"`django.contrib.admin.templatetags.admin_urls.add_preserved_filters()` loses repeated query parameters when restoring changelist filters from an admin change form.

**Reproduction**

Use a changelist URL containing repeated parameters:
    
{{{
/admin/?X__id__exact=57&X__id__exact=54
}}}

After opening an object, the change form receives:
    
{{{
_changelist_filters=X__id__exact%3D57%26X__id__exact%3D54
}}}

The admin Close/back URL is then generated as:
    
{{{
/admin/?X__exact=54
}}}

The first value has been discarded.

**Cause**

`add_preserved_filters()` repeatedly converts `parse_qsl()` results to a regular dictionary.

I have a fix prepared that we already use in a fork and can issue a PR when this gets accepted."	Bug	assigned	Forms	6.1	Normal			ollehu	Unreviewed	1	0	0	0	0	0