Improve deprecation message for issue 8368

[sbidoul]

When setup.py install fails and setup.py bdist_wheel failed too, it is most probably for the same reason.
Reporting a deprecation warning about the failed wheel build in that case is causing noise in reports for #8368. What we are really interested in is reports about packages that can install via setup.py install but fail building a wheel.

This PR makes the deprecation look like this:

$ pip install -f pip/tests/data/packages/ wheelbroken
Looking in links: pip/tests/data/packages/
Processing ./pip/tests/data/packages/wheelbroken-0.1.tar.gz
Building wheels for collected packages: wheelbroken
  Building wheel for wheelbroken (setup.py) ... error
  ERROR: Command errored out with exit status 1:
   command: /home/sbi-local/.virtualenvs/tempenv-04a2234147f66/bin/python -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-7y0wc2c_/wheelbroken/setup.py'"'"'; __file__='"'"'/tmp/pip-install-7y0wc2c_/wheelbroken/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' bdist_wheel -d /tmp/pip-wheel-gswzfp2o
       cwd: /tmp/pip-install-7y0wc2c_/wheelbroken/
  Complete output (5 lines):
  Traceback (most recent call last):
    File "<string>", line 1, in <module>
    File "/tmp/pip-install-7y0wc2c_/wheelbroken/setup.py", line 8, in <module>
      raise FakeError('this package designed to fail on bdist_wheel')
  __main__.FakeError: this package designed to fail on bdist_wheel
  ----------------------------------------
  ERROR: Failed building wheel for wheelbroken
  Running setup.py clean for wheelbroken
Failed to build wheelbroken
Installing collected packages: wheelbroken
    Running setup.py install for wheelbroken ... done
  DEPRECATION: wheelbroken was installed using the legacy 'setup.py install' method, because a wheel could not be built for it. pip 21.0 will remove support for this functionality. A possible replacement is to fix the wheel build issue reported above. You can find discussion regarding this at https://github.com/pypa/pip/issues/8368.
Successfully installed wheelbroken-0.1

[uranusjr]

Do we rollback previous setup.py install changes when a later package fails to install? (I believe wheel installations are rolled back.) Of that’s the case, maybe it’d be a better idea to show only one message when all installations succeed, instead of one message for each package?

[sbidoul]

Do we rollback previous setup.py install changes when a later package fails to install

@uranusjr I don't think so. I tried pip install -f pip/tests/data/packages/ wheelbroken psutil where setup.py install of wheelbroken succeeds and setup.py install of psutil fails and I end up with only wheelbroken installed and the deprecation warning for it only.

[uranusjr]

That’s unfortunate, although not surprising since setup.py install is difficult to manage (which is why we want it to go away in the first place). I guess this is the best approach then.

[uranusjr]

@pradyunsg Would it be possible to have one last 20.2 release for this, if nothing else comes up? I really don’t want to deal with the bogus issues for three months.

[pradyunsg]

Sure. 👍🏽

Someone needs to add a NEWS file here tho. :)

[sbidoul]

I added the news file.

I also changed install success detection to consider the success flag instead of the absence of exception.

I must say I dont quite understand this block... 🤷‍♂️

pip/src/pip/_internal/req/req_install.py

Lines 859 to 861 in ea10d0e

	except Exception:
	self.install_succeeded = True
	raise

[pfmoore]

See here:

pip/src/pip/_internal/req/__init__.py

Lines 92 to 96 in ea10d0e

	except Exception:
	# if install did not succeed, rollback previous uninstall
	if uninstalled_pathset and not requirement.install_succeeded:
	uninstalled_pathset.rollback()
	raise

If the install didn't succeed, we roll back, which we can't do for a legacy install... It's a nasty bodge to use the success flag like that, but that's true of a lot of pip's code 🙂

[sbidoul]

Thanks for the explanation @pfmoore 🙈 🙉 🙊 :)

It's 🟢 now.

[pradyunsg]

I'm gonna merge and release this sometime tomorrow next week, if no one has holler'd here to ask me to not do it. :)

[pradyunsg]

I'd set the calendar reminder for the wrong week. :)

[Muheeb42318]

I get an error while installing librec. Can somebody help? It says "Error while installing librec- "failed building wheel for librec "

ERROR: Failed building wheel for librec
Running setup.py clean for librec
Failed to build librec
DEPRECATION: Could not build wheels for librec which do not use PEP 517. pip wil
l fall back to legacy 'setup.py install' for these. pip 21.0 will remove support
for this functionality. A possible replacement is to fix the wheel build issue
reported above. You can find discussion regarding this at https://github.com/pyp
a/pip/issues/8368.
Installing collected packages: librec

error: command 'C:\Program Files (x86)\Microsoft Visual Studio\2019\Buil
dTools\VC\Tools\MSVC\14.27.29110\bin\HostX86\x64\cl.exe' failed with exi
t status 2