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
23594	Deepcopy on ErrorDict shows unexpected duplicates	Troy Grosfield	Tim Graham	"Using python 3.4, django 1.7, you'll see the following error when deepcopying  ErrorDicts:

{{{
$ python
Python 3.4.1 (default, Aug 24 2014, 21:32:40)
[GCC 4.2.1 Compatible Apple LLVM 5.1 (clang-503.0.40)] on darwin
Type ""help"", ""copyright"", ""credits"" or ""license"" for more information.
>>> from copy import deepcopy
>>> from django.forms.utils import ErrorList
>>> from django.forms.utils import ErrorDict
>>>
>>>
>>> ed = ErrorDict()
>>> ed['__all__'] = ErrorList(['first thing'])
>>> ed
{'__all__': ['first thing']}
>>> ed_copy = deepcopy(ed)
>>> ed_copy
{'__all__': ['first thing', 'first thing']}   # <-- what happened here? why is ""first thing"" listed twice?
>>> len(ed['__all__']) == len(ed_copy['__all__'])
False
}}}

Why did ""first thing"" get copied twice? "	Bug	closed	Forms	1.7	Release blocker	fixed		Loic Bistuer	Ready for checkin	1	0	0	0	0	0