python2Packages.PyJWT fails to build

[lapp0]

Describe the bug
python2Packages.PyJWT fails to build since it was upgraded to 2.0.1 in this change.

I ran into this issue trying to build nixops, logs in the following section.

To Reproduce
Either

nix-shell -p nixops

or

nix-shell -p python2Packages.pyjwt

these derivations will be built:
  /nix/store/1sil47bdavwacfanpqlpw2dlpprpxb09-python2.7-PyJWT-2.0.1.drv
building '/nix/store/1sil47bdavwacfanpqlpw2dlpprpxb09-python2.7-PyJWT-2.0.1.drv'...
Sourcing python-remove-tests-dir-hook
Sourcing python-catch-conflicts-hook.sh
Sourcing python-remove-bin-bytecode-hook.sh
Sourcing setuptools-build-hook
Using setuptoolsBuildPhase
Using setuptoolsShellHook
Sourcing pip-install-hook
Using pipInstallPhase
Sourcing python-imports-check-hook.sh
Using pythonImportsCheckPhase
Sourcing setuptools-check-hook
unpacking sources
unpacking source archive /nix/store/w1zbzlnx1dwcd2pvg5094550iljjmrai-PyJWT-2.0.1.tar.gz
source root is PyJWT-2.0.1
setting SOURCE_DATE_EPOCH to timestamp 1610906219 of file PyJWT-2.0.1/setup.cfg
patching sources
substituteStream(): WARNING: pattern 'pytest>=4.0.1,<5.0.0' doesn't match anything in file 'setup.py'
configuring
no configure script, doing nothing
building
Executing setuptoolsBuildPhase
Traceback (most recent call last):
  File "nix_run_setup", line 8, in <module>
    exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\\r\\n', '\\n'), __file__, 'exec'))
  File "setup.py", line 5, in <module>
    setup()
  File "/nix/store/8yqk17gg1594prmi5hi5ggm9ifr8l4cx-python2.7-setuptools-44.0.0/lib/python2.7/site-packages/setuptools/__init__.py", line 145, in setup
    return distutils.core.setup(**attrs)
  File "/nix/store/r8xqa85n5m0xg7p6rymwh0ldzf0h5wqv-python-2.7.18/lib/python2.7/distutils/core.py", line 124, in setup
    dist.parse_config_files()
  File "/nix/store/8yqk17gg1594prmi5hi5ggm9ifr8l4cx-python2.7-setuptools-44.0.0/lib/python2.7/site-packages/setuptools/dist.py", line 702, in parse_config_files
    ignore_option_errors=ignore_option_errors)
  File "/nix/store/8yqk17gg1594prmi5hi5ggm9ifr8l4cx-python2.7-setuptools-44.0.0/lib/python2.7/site-packages/setuptools/config.py", line 121, in parse_configuration
    meta.parse()
  File "/nix/store/8yqk17gg1594prmi5hi5ggm9ifr8l4cx-python2.7-setuptools-44.0.0/lib/python2.7/site-packages/setuptools/config.py", line 426, in parse
    section_parser_method(section_options)
  File "/nix/store/8yqk17gg1594prmi5hi5ggm9ifr8l4cx-python2.7-setuptools-44.0.0/lib/python2.7/site-packages/setuptools/config.py", line 399, in parse_section
    self[name] = value
  File "/nix/store/8yqk17gg1594prmi5hi5ggm9ifr8l4cx-python2.7-setuptools-44.0.0/lib/python2.7/site-packages/setuptools/config.py", line 184, in __setitem__
    value = parser(value)
  File "/nix/store/8yqk17gg1594prmi5hi5ggm9ifr8l4cx-python2.7-setuptools-44.0.0/lib/python2.7/site-packages/setuptools/config.py", line 515, in _parse_version
    version = self._parse_attr(value, self.package_dir)
  File "/nix/store/8yqk17gg1594prmi5hi5ggm9ifr8l4cx-python2.7-setuptools-44.0.0/lib/python2.7/site-packages/setuptools/config.py", line 350, in _parse_attr
    value = getattr(module, attr_name)
AttributeError: 'module' object has no attribute '__version__'
builder for '/nix/store/1sil47bdavwacfanpqlpw2dlpprpxb09-python2.7-PyJWT-2.0.1.drv' failed with exit code 1
error: build of '/nix/store/1sil47bdavwacfanpqlpw2dlpprpxb09-python2.7-PyJWT-2.0.1.drv' failed

Additional context
python2Packages.PyJWT is used by a variety of packages including conan (fixed here via an override).

Notify maintainers
@prikhi

Metadata
Please run nix-shell -p nix-info --run "nix-info -m" and paste the result.

 - system: `"x86_64-linux"`
 - host os: `Linux 5.10.22, NixOS, 20.09.git.b82a99fd5d9 (Nightingale)`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.3.10`
 - channels(andrew): `"nixos-20.09.1599.d105075a1fd"`
 - nixpkgs: `/etc/nixos/nixpkgs`

Because multiple packages use python2 and depend on PyJWT, perhaps rather than writing an override for each package depending on it, python2Packages.PyJWT should use a different version than in python3?

Slightly related NixOS/nixops#504

[fabaff]

PyJTW > 2.0.0 doesn't support Python 2 any more.

[fabaff]

Because multiple packages use python2 and depend on PyJWT

About how many packages are we talking here. I guess that there are 20-25 packages in total which depend on PyJWT but not many that are still supporting Python 2.

[dotlambda]

@NixOS/nixops-committers Someone will have to package a Python 2 version of PyJWT.

[lapp0]

I'm not sure how many depend on python2 PyJWT. Ideally unsupported versions of python are phased out.

I'm a bit confused here, this comment from April 2020 said nixops is python3 only NixOS/nixops#504 (comment)

However,

nix-store -q --referrers /nix/store/1sil47bdavwacfanpqlpw2dlpprpxb09-python2.7-PyJWT-2.0.1.drv

/nix/store/7n78bd1zqazqiq9x0my2x8l5xjg46sq1-shell.drv
/nix/store/9hkzmbmy7vlvrk50rv0iwigxkal3wrcb-python2.7-adal-1.2.6.drv

nix-store -q --referrers /nix/store/9hkzmbmy7vlvrk50rv0iwigxkal3wrcb-python2.7-adal-1.2.6.drv

/nix/store/bzjrqiwsdz9is1xkwq5n3vd45ch1fldb-nixops-1.7.drv

Is the actual bug that nixops depends on python2 adal when it shouldn't?

[dotlambda]

Is the actual bug that nixops depends on python2 adal when it shouldn't?

No, nixops refers to version 1.7 which uses Python 2 while nixopsUnstable refers to version 2.0 which uses Python 3.

[lapp0]

Thanks! Seems like they're quite close to 2.0's release. NixOS/nixops#1242

[mweinelt]

Fixed in #122142.