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
28923	TypeError: 'set' object is not reversible	Edwar Baron	nobody	"I have updated the version of Django to 2.0 in an existing project, and I have followed all the steps necessary for the project to be compatible.

but I'm having problems in the administrator when creating or editing a model that uses attributes from this **django-markdownx** library

the current configuration of the project of the usa packages:
{{{
amqp (2.2.2)
apipkg (1.4)
asn1crypto (0.23.0)
attrs (17.3.0)
Babel (2.5.1)
bcrypt (3.1.4)
billiard (3.5.0.3)
celery (4.1.0)
certifi (2017.11.5)
cffi (1.11.2)
chardet (3.0.4)
coreapi (2.3.3)
coreschema (0.0.4)
coverage (4.4.2)
cryptography (2.1.4)
Django (2.0)
django-celery-results (1.0.1)
django-colorfield (0.1.14)
django-constance (2.0.0)
django-cors-headers (2.1.0)
django-environ (0.4.4)
django-excel-response (2.0.2)
django-extensions (1.9.8)
django-filter (1.1.0)
django-markdownx (2.0.21)
django-picklefield (1.0.0)
django-redis (4.8.0)
django-redis-cache (1.7.1)
django-rest-swagger (2.1.2)
djangorestframework (3.7.3)
et-xmlfile (1.0.1)
execnet (1.5.0)
Fabric3 (1.13.1.post1)
factory-boy (2.7.0)
fake-factory (0.7.4)
flower (0.9.2)
idna (2.6)
isort (4.2.15)
itypes (1.1.0)
jdcal (1.3)
Jinja2 (2.10)
kombu (4.1.0)
Markdown (2.6.10)
MarkupSafe (1.0)
olefile (0.44)
opbeat (3.6.0)
openapi-codec (1.3.2)
openpyxl (2.4.9)
paramiko (2.4.0)
pep8 (1.7.1)
Pillow (4.3.0)
pip (9.0.1)
pluggy (0.6.0)
psycopg2 (2.7.3.2)
py (1.5.2)
pyasn1 (0.4.2)
pycparser (2.18)
pyflakes (1.6.0)
PyNaCl (1.2.1)
pytest (3.3.1)
pytest-cache (1.0)
pytest-cov (2.5.1)
pytest-django (3.1.2)
pytest-flakes (2.0.0)
pytest-isort (0.1.0)
pytest-pep8 (1.0.6)
pytest-sugar (0.9.0)
python-dateutil (2.6.1)
pytz (2017.3)
redis (2.10.6)
requests (2.18.4)
setuptools (36.4.0)
simplejson (3.13.2)
six (1.11.0)
sorl-thumbnail (12.4.1)
termcolor (1.1.0)
tornado (4.5.2)
typing (3.6.2)
uritemplate (3.0.0)
urllib3 (1.22)
vine (1.1.4)
Werkzeug (0.13)
wheel (0.30.0)
}}}

the error is caused in this file 

{{{
File ""/usr/local/lib/python3.6/site-packages/django/forms/widgets.py"", line 114, in merge

...
        combined_list = list(list_1)
        last_insert_index = len(list_1)
        # Walk list_2 in reverse, inserting each element into combined_list if
        # it doesn't already exist.
        for path in reversed(list_2):

TypeError: 'set' object is not reversible
...

Local variables in frame

last_insert_index	0
combined_list	[]
list_2	                set(['markdownx/js/markdownx.js'])
list_1	                []
}}}

the variable **list_2** is a list of set type

the simple solution that I think

is to convert that variable to a **list**"	Bug	new	Forms	2.0	Release blocker		reversed		Unreviewed	0	0	0	0	0	0