Issue 24086: Configparser interpolation is unexpected (original) (raw)

Issue24086

Created on 2015-04-30 19:12 by tbekolay, last changed 2022-04-11 14:58 by admin. This issue is now closed.

Messages (5)
msg242283 - (view)	Author: Trevor Bekolay (tbekolay)	Date: 2015-04-30 19:12
I was having an issue installing a package in Python 3, which installed properly in Python 2. This is the error message I got: Complete output from command python setup.py egg_info: Traceback (most recent call last): ... snip unhelpful traceback ... File "/usr/local/Cellar/python3/3.4.3/Frameworks/Python.framework/Versions/3.4/lib/python3.4/configparser.py", line 423, in _interpolate_some "found: %r" % (rest,)) configparser.Interpolation ---------------------------------------- Command "python setup.py egg_info" failed with error code 1 in /private/var/folders/12/p4ngkfbx2pnb1ln81csjb19c0000gn/T/pip-build-6xhgg5x6/nengo This wasn't a super helpful error message. I managed to figure out that Python 3 (or setuptools?) was attempting to parse my ~/.pypirc file, which raised a configparser.InterpolationSyntaxError because my password contained a percent-sign. Configparser doesn't try to interpolate this string in Python 2, so it worked fine. As a workaround, I've changed my PyPI password, but this failure was quite surprising to me. As for what I would expect to happen, I would not expect interpolation to happen if I don't want it to happen. All of the examples shown on in the docs use the syntax "%(key)s" or "${key}". If this is the only way to interpolate, then why is "%" ambiguous? Surely we can look forward one character, and if it's not "(" then "%" should be interpreted literally. Instead, configparser requires me to disambiguate with "%%". But, this would cause my string to be parsed incorrectly in Python 2's configparser, so I'm unable to make that change.
msg242292 - (view)	Author: Łukasz Langa (lukasz.langa) *	Date: 2015-04-30 23:17
This is expected behaviour but I agree the error message should be improved. There are people using interpolation in .pypirc, if you don't want that, just use a double % sign and it will do the right thing. You don't have to change your password. I'll leave that open to find what's the source of the exception and maybe add a more helpful message there.
msg242564 - (view)	Author: Trevor Bekolay (tbekolay)	Date: 2015-05-04 17:09
Thanks for the quick response! I can see the use case for using interpolation in .pypirc. Unfortunately for me, I push releases for both Python 2 and Python 3, so having the double percent sign will cause problems for me on Python 2. The exception that's being raised is at line 442 (https://hg.python.org/cpython/file/default/Lib/configparser.py#l442). The message itself seems to have the right information, but setuptools seems to mangle it (perhaps InterpolationSyntaxError needs a __repr__ or __str__?)
msg245120 - (view)	Author: Jens Diemer (jens)	Date: 2015-06-10 07:45
IMHO i ran into the same bug, try to "./setup.py upload" with my new password in ~/.pypirc: configparser.InterpolationSyntaxError: '%' must be followed by '%' or '(', found: "%foobar" This is a limitation of the configparser... But what's about to validate this on the "set PyPi password view" ? So that's impossible to set a PyPi password which can't be parsed by configparser ?
msg268308 - (view)	Author: Łukasz Langa (lukasz.langa) *	Date: 2016-06-12 01:12
This is solved upstream in setuptools by disabling configparser interpolation.