Pip-tools: pip-sync removes pkg-resoources

[graingert]

Describe the issue briefly here.

Steps to replicate

$ cat requirements-dev.txt 
#
# This file is autogenerated by pip-compile
# To update, run:
#
#    pip-compile --output-file requirements-dev.txt requirements-dev.in
#
click==6.6                # via pip-tools
first==2.0.1              # via pip-tools
mypy-lang==0.4.4
pip-tools==1.7.0
pluggy==0.3.1             # via tox
py==1.4.31                # via tox
six==1.10.0               # via pip-tools
tox==2.3.1
virtualenv==15.0.3        # via tox
wheel==0.29.0

# The following packages are commented out because they are
# considered to be unsafe in a requirements file:
# pip
# setuptools

Expected result

Actual result

$ pip-sync requirements-dev.txt 
Uninstalling pkg-resources-0.0.0:
  Successfully uninstalled pkg-resources-0.0.0

[graingert]

Now I can't install any packages

[das-g]

I noticed this, too. I guess this is probably due to (or for the same reason as) pypa/pip#4022, which according to @RonnyPfannschmidt is caused by a bug in ubuntu. (Filed as https://bugs.launchpad.net/ubuntu/+source/python-pip/+bug/1635463)

[estan]

Our CI builds recently started failing because of this. Since it seems the Ubuntu bug is slow-moving, would it be OK to add @graingert's workaround to official piptools? It just adds pkg-resources to PACKAGES_TO_IGNORE in sync.py.

[das-g]

it seems the Ubuntu bug is slow-moving

Does anyone know what would have to change on the Ubuntu side to fix this properly? Can we send them a patch to speed things up?

Until then, an official pip-tools release with the workaround merged would be much appreciated.

[vphilippon]

@das-g The bad news is, we're currently blocked and can't do any official release of pip-tools (see #531).

As soon as we're able to make new releases, I'll check to add that package to the list, unless Ubuntu manages to fix that first.

[vphilippon]

Closed by #555