urlize on URL with incomplete query string adds equal sign.

[Jochen Garcke]

If one uses urlize in a template {{ work_urls|urlize }} on URLs such as
​http://www.isfdb.org/cgi-bin/pl.cgi?284309
an equal sign will be added
​http://www.isfdb.org/cgi-bin/pl.cgi?284309=
The resulting URL fails at that site.

Granted, I suspect that this is likely not a standard conform use of '?' by that site, but still unwanted behaviour.

[Mariusz Felisiak]

Thanks for the report. ​smart_urlquote() adds a trailing equal sign. I noticed that parse_qsl() raises:

  File "/usr/lib/python3.6/urllib/parse.py", line 693, in parse_qsl
    raise ValueError("bad query field: %r" % (name_value,))
ValueError: bad query field: '284309'

when we add strict_parsing=True flag, hence I believe that query string used by this site is incorrect. I'm not sure that we should handle this case in Django.

[Mariusz Felisiak]

It seems that a patch is not feasible with the current implementation that uses parse_qsl(), because

>>> parse_qsl('a', keep_blank_values=True)
[('a', '')]
>>> parse_qsl('a=', keep_blank_values=True)
[('a', '')]

so would have to add a special workaround for this single case, what is not worth it.