How does

./pants export --resolve=...

(or more likely the underlying

pex

?) determine which version of

pip

and

setuptools

gets installed in the exported venv? The version of

pip

is not locked, so I'm not surprised to see a different version when exported with any of

python3.6

,

python3.7

, and

python3.8

. But

setuptools

is in the lockfile. When I export with

python3.6

or

python3.7

, I get the version of setuptools in my lockfile. With

python3.8

, I get a newer version of

setuptools

. NB: This is with the default

--py-resolve-format=mutable_virtualenv

. With

--py-resolve-format=symlinked_immutable_virtualenv

then all of them have the correct locked version of

setuptools

and do not have

pip

. I'm on pants 2.16.0a0

For Python 3, venvs are bootstrapped via

-m venv

and Pip is installed via: https://github.com/pantsbuild/pex/blob/86ecdeb52a3f8ce434339cdf6d62d382fb99dfd0/pex/venv/virtualenv.py#L350-L379