Prefer virtualenv over venv

[ghost]

virtualenv includes seed packages (pip, setuptools, wheel) so creating virtualenvs with those already included is much faster than using venv and then installing them with pip. There should at least be an option to prefer virtualenv even if venv is available.

[native-api]

Virtualenv is already preferred if it's installed for the active Python version or if -p is specified:

pyenv-virtualenv/bin/pyenv-virtualenv

Lines 158 to 165 in 6742d0e

	# Use `python -m venv` only if there is venv available, virtualenv is not installed, and `-p` not given
	if [ -n "${HAS_CONDA}" ]; then
	USE_CONDA=1
	else
	if [ -n "${HAS_M_VENV}" ] && [ -z "${HAS_VIRTUALENV}" ] && [ -z "${VIRTUALENV_PYTHON}" ]; then
	USE_M_VENV=1
	fi
	fi

[native-api]

I guess there could be an option envvar added to prefer Virtualenv even if Venv is present.

That's because the current logic is that there's no need for Virtualenv if Venv can do the job, too -- but as per OP, there may be reasons to prefer Virtualenv regardless.

[matteosantama]

Virtualenv is already preferred if it's installed for the active Python version or if -p is specified

FWIW with pyenv==2.2.3 and pyenv-virtualenv==1.1.5 the -p flag is invalid

EDIT: maybe I'm using it incorrectly?

pyenv virtualenv -p 3.8.12 myvenv