Vendoring update helper is not working

[pradyunsg]

Environment

• pip version: 19.1.1 (or dev)
• Python version: 3.7.4
• OS: MacOS

Description

Trying to re-vendor packages with invoke vendoring.update fails. We're hitting #6222 there.

Expected behavior

Packages can be re-vendored cleanly.

How to Reproduce

1. Install all dependencies for invoke and our tasks/.
2. Run invoke vendoring.update.

Output

Actual error when flit fails to install with setup.py install.

  Running setup.py install for flit ... error
    ERROR: Complete output from command /Users/pradyunsg/.pyenv/versions/3.7.4/Python.framework/Versions/3.7/bin/python3.7 -u -c 'import setuptools, tokenize;__file__='"'"'/private/var/folders/4d/bt0_xfx56bjfmmt2bv3r5_qh0000gn/T/pip-install-mnfb_y9p/flit/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /private/var/folders/4d/bt0_xfx56bjfmmt2bv3r5_qh0000gn/T/pip-record-g82cm62s/install-record.txt --single-version-externally-managed --compile:
    ERROR: Traceback (most recent call last):
      File "<string>", line 1, in <module>
    ModuleNotFoundError: No module named 'setuptools'

[pradyunsg]

Ahahaah. I'm gonna use pip 18.1 to work around that issue. :D

Do I feel bad? Yes... But no one who's affected by it has stepped up to fix it and it's not my problem to fix everything. And, #6222 is a tricky beast anyway.

[yan12125]

But no one who's affected by it has stepped up to fix it

I think #6606 is a fix?

[pradyunsg]

I think #6606 is a fix?

Whoopsies, sorry about that.

AFAICT, it's not in a mergable state though. Anyway, I'm sleepy right now so I'm definitely should not doing reviews for PEP 517 stuff, or merging PRs anyway.

[pradyunsg]

Closing this out. I've probably rewritten this twice, and didn't find this issue on both occasions. XD