Compilation Failures with Py_DEBUG enabled

[skadz]

Py_DEBUG and Py_LIMITED_API are not compatible, so compilation fails when Py_DEBUG is enabled.

We should add a check for Py_DEBUG and make sure we do not use the limited api if it is in place.

[asottile]

no we shouldn't

[skadz]

So, you would rather your library not work with Py_DEBUG or are you telling me there is a better fix that you would like to implement?

[asottile]

it works fine for me -- please describe your actual use case instead of jumping to a solution

[skadz]

gcc -Wno-unused-result -Wsign-compare -g -Og -Wall -fPIC -DPy_LIMITED_API -I./libsass/include -I/usr/local/include/python3.8d -c _sass.c -o build/temp.linux-aarch64-cpython-38-pydebug/_sass.o -fPIC -std=gnu++0x -Wall -Wno-parentheses -Werror=switch -DLIBSASS_VERSION=\"3.6.5\"
        cc1: warning: command-line option '-std=gnu++11' is valid for C++/ObjC++ but not for C
        In file included from /usr/local/include/python3.8d/Python.h:88,
                         from _sass.c:1:
        /usr/local/include/python3.8d/object.h:63:2: error: #error Py_LIMITED_API is incompatible with Py_DEBUG, Py_TRACE_REFS, and Py_REF_DEBUG
           63 | #error Py_LIMITED_API is incompatible with Py_DEBUG, Py_TRACE_REFS, and Py_REF_DEBUG
              |  ^~~~~
        /tmp/pip-build-env-h82wsj1h/overlay/lib/python3.8/site-packages/setuptools/config/setupcfg.py:520: SetuptoolsDeprecationWarning: The license_file parameter is deprecated, use license_files instead.
          warnings.warn(msg, warning_class)
        error: command '/usr/bin/gcc' failed with exit code 1
        [end of output]

    note: This error originates from a subprocess, and is likely not a problem with pip.
    ERROR: Failed building wheel for libsass
  Failed to build libsass
  ERROR: Could not build wheels for libsass, which is required to install pyproject.toml-based projects

[asottile]

please describe your actual use case

[skadz]

I moved to a debug version of python to debug some code by compiling with --with-pydebug. When I did, libsass failed to compile when I ran poetry install for my application with the error above. I am unable to run my application without it, which means I cannot do the debugging I need to do, which is blocking me from doing my job. I was able to fix this issue with the PR I submitted.

I am running the latest release of Python 3.8 on Alpine Linux.

[asottile]

you're free to fork 👍

this isn't a problem in python3.10+ so I don't want to carry code specifically for old pythons

[skadz]

There are still almost 2 years of support for Python 3.8 and another year past that for 3.9 and your library works with neither under pydebug, so it's disappointing that you are cutting off support for versions that are supported for a long time. Especially when it's a 4 line change (one being a comment). I've updated my change to look for versions now too, so it will work the way you want under 3.10 and will now work under pydebug under 3.9 and below, which will help folks who aren't bleeding edge (like most companies in the world), but it sounds as if that is not important to you.

# Py_LIMITED_API does not work for Py_DEBUG either in versions less than 3.10
if distutils.sysconfig.get_config_var('Py_DEBUG') == 1 and sys.version_info < (3,10):
    py_limited_api = False
    define_macros = []

[asottile]

it's not "just a 4 line change" -- you're introducing a deprecated library for a niche-at-best use case that we don't test and don't support. your attitude is not appreciated and additionally, neither you nor your company are sponsoring development