Unable to install mopidy from the Git repo inside a virtualenv

[Steap]

Describe the bug
I am unable to install mopidy from the Git repo inside a virtualenv even though I followed the instructions.

How to reproduce

$ mkdir ~/mopidy-dev
$ source /usr/share/virtualenvwrapper/virtualenvwrapper.sh
$ mkvirtualenv -a ~/mopidy-dev --python $(which python3.9) --system-site-packages mopidy
(mopidy) $ git clone https://github.com/mopidy/mopidy.git
(mopidy) $ cd mopidy
(mopidy) $ pip install --upgrade --editable .
Obtaining file:///home/cyril/mopidy-dev/mopidy
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
    Preparing wheel metadata ... done
Collecting Pykka>=2.0.1
  Using cached pykka-3.0.2-py3-none-any.whl (27 kB)
Requirement already satisfied: setuptools in /home/cyril/.virtualenvs/mopidy/lib/python3.9/site-packages (from Mopidy==3.2.0) (44.1.1)
Requirement already satisfied: requests>=2.0 in /home/cyril/.local/lib/python3.9/site-packages (from Mopidy==3.2.0) (2.26.0)
Requirement already satisfied: tornado>=4.4 in /usr/lib/python3/dist-packages (from Mopidy==3.2.0) (6.1)
Requirement already satisfied: urllib3<1.27,>=1.21.1 in /usr/lib/python3/dist-packages (from requests>=2.0->Mopidy==3.2.0) (1.26.5)
Requirement already satisfied: charset-normalizer~=2.0.0 in /home/cyril/.local/lib/python3.9/site-packages (from requests>=2.0->Mopidy==3.2.0) (2.0.7)
Requirement already satisfied: certifi>=2017.4.17 in /usr/lib/python3/dist-packages (from requests>=2.0->Mopidy==3.2.0) (2020.6.20)
Requirement already satisfied: idna<4,>=2.5 in /usr/lib/python3/dist-packages (from requests>=2.0->Mopidy==3.2.0) (2.10)
Installing collected packages: Pykka, Mopidy
  Running setup.py develop for Mopidy
    ERROR: Command errored out with exit status 1:
     command: /home/cyril/.virtualenvs/mopidy/bin/python -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/home/cyril/mopidy-dev/mopidy/setup.py'"'"'; __file__='"'"'/home/cyril/mopidy-dev/mopidy/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' develop --no-deps
         cwd: /home/cyril/mopidy-dev/mopidy/
    Complete output (30 lines):
    running develop
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/home/cyril/mopidy-dev/mopidy/setup.py", line 3, in <module>
        setup()
      File "/usr/lib/python3/dist-packages/setuptools/__init__.py", line 153, in setup
        return distutils.core.setup(**attrs)
      File "/usr/lib/python3/dist-packages/setuptools/_distutils/core.py", line 148, in setup
        dist.run_commands()
      File "/usr/lib/python3/dist-packages/setuptools/_distutils/dist.py", line 967, in run_commands
        self.run_command(cmd)
      File "/usr/lib/python3/dist-packages/setuptools/_distutils/dist.py", line 985, in run_command
        cmd_obj.ensure_finalized()
      File "/usr/lib/python3/dist-packages/setuptools/_distutils/cmd.py", line 107, in ensure_finalized
        self.finalize_options()
      File "/usr/lib/python3/dist-packages/setuptools/command/develop.py", line 52, in finalize_options
        easy_install.finalize_options(self)
      File "/usr/lib/python3/dist-packages/setuptools/command/easy_install.py", line 293, in finalize_options
        self.set_undefined_options(
      File "/usr/lib/python3/dist-packages/setuptools/_distutils/cmd.py", line 287, in set_undefined_options
        src_cmd_obj.ensure_finalized()
      File "/usr/lib/python3/dist-packages/setuptools/_distutils/cmd.py", line 107, in ensure_finalized
        self.finalize_options()
      File "/usr/lib/python3/dist-packages/setuptools/command/install_lib.py", line 17, in finalize_options
        self.set_undefined_options('install',('install_layout','install_layout'))
      File "/usr/lib/python3/dist-packages/setuptools/_distutils/cmd.py", line 290, in set_undefined_options
        setattr(self, dst_option, getattr(src_cmd_obj, src_option))
      File "/usr/lib/python3/dist-packages/setuptools/_distutils/cmd.py", line 103, in __getattr__
        raise AttributeError(attr)
    AttributeError: install_layout
    ----------------------------------------
ERROR: Command errored out with exit status 1: /home/cyril/.virtualenvs/mopidy/bin/python -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/home/cyril/mopidy-dev/mopidy/setup.py'"'"'; __file__='"'"'/home/cyril/mopidy-dev/mopidy/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' develop --no-deps Check the logs for full command output.

I tried upgrading setuptools with:

pip install -U setuptools

Which did not help

Expected behaviour
No error should be returned and "pip install" should be successful.

Environment
Please complete the following information:

• I am running Debian Sid
• Not even running Mopidy since I cannot install it
• The config is not relevant here
• The output of mopidyctl is not relevant here

Additional context
This works fine on Debian testing and in an Ubuntu 20.04 VM.

[kingosticks]

Sounds like https://www.mail-archive.com/debian-bugs-dist@lists.debian.org/msg1837744.html rather than our issue.

[kingosticks]

The workaround to export SETUPTOOLS_USE_DISTUTILS=stdlib works for me. Don't get me wrong, it's horrible but the bug(s) in pip/setiptools/debian seem to be really old. Not sure why Debian are ignoring it.

[Steap]

I had never faced this issue before. I can confirm the workaround is working. Thanks for your help and sorry for the noise, I'll close this issue.

[kingosticks]

No, not at all. Certainly worthwhile reporting. I only ran into it myself last night on my newly updated system. I just don't think there's anything sensible we can do here to avoid it. I could add a little note to the docs and I expect as soon as I do that they'll fix it!