failure on Ubuntu 18.04, ModuleNotFoundError: No module named 'setuptools'

Hi! I’m pretty clueless about Python, GitHub Actions, etc. I’ve got a project that uses install-qt-action; it has been working nicely for months, using @v2 (but this issue is for @v3, read on), and then that recently stopped working on macos-10.15 with this error (log: https://github.com/MesserLab/SLiM/runs/8253692308?check_suite_focus=true):

python3 -m pip install py7zr==0.16.1
Collecting py7zr==0.16.1
  Downloading py7zr-0.16.1-py3-none-any.whl (65 kB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 65.7/65.7 kB 1.5 MB/s eta 0:00:00
Collecting texttable
  Downloading texttable-1.6.4-py2.py3-none-any.whl (10 kB)
Collecting pyzstd<0.15.0,>=0.14.4
  Downloading pyzstd-0.14.4.tar.gz (659 kB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 659.7/659.7 kB 22.0 MB/s eta 0:00:00
  Preparing metadata (setup.py): started
  Preparing metadata (setup.py): finished with status 'done'
Collecting bcj-cffi<0.6.0,>=0.5.1
  Downloading bcj-cffi-0.5.1.tar.gz (35 kB)
  Installing build dependencies: started
  Installing build dependencies: finished with status 'done'
  Getting requirements to build wheel: started
  Getting requirements to build wheel: finished with status 'done'
  Installing backend dependencies: started
  Installing backend dependencies: finished with status 'done'
  Preparing metadata (pyproject.toml): started
  Preparing metadata (pyproject.toml): finished with status 'done'
  WARNING: Requested bcj-cffi<0.6.0,>=0.5.1 from https://files.pythonhosted.org/packages/97/9c/681442a5b3a5bb3a1210a8ddc6cc6f6a47ea90834b80daa15af767b1c29a/bcj-cffi-0.5.1.tar.gz (from py7zr==0.16.1), but installing version 0.0.0
Discarding https://files.pythonhosted.org/packages/97/9c/681442a5b3a5bb3a1210a8ddc6cc6f6a47ea90834b80daa15af767b1c29a/bcj-cffi-0.5.1.tar.gz (from https://pypi.org/simple/bcj-cffi/): Requested bcj-cffi<0.6.0,>=0.5.1 from https://files.pythonhosted.org/packages/97/9c/681442a5b3a5bb3a1210a8ddc6cc6f6a47ea90834b80daa15af767b1c29a/bcj-cffi-0.5.1.tar.gz (from py7zr==0.16.1) has inconsistent version: filename has '0.5.1', but metadata has '0.0.0'
ERROR: Could not find a version that satisfies the requirement bcj-cffi<0.6.0,>=0.5.1 (from py7zr) (from versions: 0.3.1, 0.4.0, 0.5.0, 0.5.1)
ERROR: No matching distribution found for bcj-cffi<0.6.0,>=0.5.1
Error: The process 'python3' failed with exit code 1

After a bit of head-scratching I realized that @v3 had been released so I updated my tests.yml to that. Unfortunately, that now gives a different error, now on ubuntu-18.04 (log: https://github.com/MesserLab/SLiM/runs/8254237001?check_suite_focus=true):

/usr/bin/python3 -m pip install setuptools wheel py7zr==0.19.* aqtinstall==2.1.*
Collecting setuptools
  Downloading https://files.pythonhosted.org/packages/b0/3a/88b210db68e56854d0bcf4b38e165e03be377e13907746f825790f3df5bf/setuptools-59.6.0-py3-none-any.whl (952kB)
Collecting wheel
  Downloading https://files.pythonhosted.org/packages/27/d6/003e593296a85fd6ed616ed962795b2f87709c3eee2bca4f6d0fe55c6d00/wheel-0.37.1-py2.py3-none-any.whl
Collecting py7zr==0.19.*
  Downloading https://files.pythonhosted.org/packages/a2/4e/4e09d932374a0a9ced425cf438aabf385ee1dfb1157d0c8cf4de3f35babf/py7zr-0.19.0-py3-none-any.whl (65kB)
Collecting aqtinstall==2.1.*
  Downloading https://files.pythonhosted.org/packages/b8/42/dacb97cbaa19189f9595f056f67de6073b533a47359d4d4bd10ea96be5e0/aqtinstall-2.1.0-py2.py3-none-any.whl (53kB)
Collecting pyzstd>=0.14.4 (from py7zr==0.19.*)
  Downloading https://files.pythonhosted.org/packages/dc/1a/bea7694b0364981e807afe7b21639f47e559ee181b02cee11ceb3fe551b6/pyzstd-0.15.3-cp36-cp36m-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_12_x86_64.manylinux2010_x86_64.whl (377kB)
Collecting pybcj>=0.6.0 (from py7zr==0.19.*)
  Downloading https://files.pythonhosted.org/packages/26/ff/25952179fa892e7d082a34e5917d747d05a227ba3c83dd3adac1c3f0be24/pybcj-1.0.1.tar.gz (2.1MB)
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
    ModuleNotFoundError: No module named 'setuptools'

I have no idea what any of this means, but it looks like @v3 is in some way unhappy on ubuntu-18.04. My next stab in the dark will be to conditionally use either @v2 or @v3 depending upon the platform, if I can figure out the syntax for doing that. :-> But this seemed like possibly an issue worth reporting; or more likely, you can at least tell me what I’m doing wrong. Thanks.

[jurplel]

Glad I could help!

[bhaller]

OK, the new build with that fix has gotten past the Qt install on all platforms with @v3, I think, so all seems to be well. Thanks very much for your advice, flipping this flag would not have occurred to me for a very long time. :-> Closing.