installing with pip3 errors out

[callegar]

I understand that this is wanted to workaround other bugs, but
pip3 install --user retext errors producing pages of debug info, to then say

File "/tmp/pip-install-f_n60ljf/retext/setup.py", line 91, in run
      raise RuntimeError("Building wheels is disabled, because it breaks .desktop"
  RuntimeError: Building wheels is disabled, because it breaks .desktop files. See issues #452 and #497 for details.
  ----------------------------------------
  ERROR: Failed building wheel for retext
  Running setup.py clean for retext
Failed to build retext

but finally conclude

Installing collected packages: retext
    Running setup.py install for retext ... done
Successfully installed retext-7.1.0

after which retext seems to be working.
This is extremely confusing. If not building wheels is the desired outcome, can the exception be avoided or caught?

[mitya57]

Unfortunately, raising an exception is the only way to prevent pip from building the wheel.
After building wheel fails, pip falls back to setup.py install, which works absolutely fine.

I can add some text that this error should be ignored. Do you think it will be better?

[callegar]

Yes, I think that would be useful, otherwise, one will always be unsure on whether the install has succeeded or not.
Out of curiosity, is there a pip bug for this? Seems strange that a package has no way to control whether its setup should involve building a wheel or not.

[mitya57]

Unfortunately, the approach we are using is “double legacy”. First, pip does not find pyproject.toml defined in PEP 517 and falls back to calling setup.py directly. Second, building a wheel fails and it falls back to setup.py install. I doubt that pip developers will add an option to force this behavior, and I know that they want to get rid of it (see pypa/pip#8102 or this comment). And definitely sticking to it is not a long-term solution.

Instead, I think pip should pass the installation paths as PEP 517 config_settings, then I will be able to teach our build system to use them for writing the desktop file. This is discussed in pypa/pip#5771 and pypa/pip#2677.