id	summary	reporter	owner	description	type	status	priority	milestone	component	resolution	keywords	cc	parents
5064	Add option to override ./configure'd virtualenv	ayleph		"`./configure` searches for `virtualenv` in the following order:

- `virtualenv`
- `virtualenv3`
- `virtualenv2`

Once a match is found, the search terminates. If a user has both python2 and python3 installed, then the python3 `virtualenv` may be configured for use, even when `--with-python3` is not specified. This results in an error for users who intend to use (or need to use) python2.

In the case of Arch Linux, `virtualenv` is the python3 package, and `virtualenv2` is the python2 package. When I run `./configure` without specifying `--with-python3`, the python3 `virtualenv` is configured even though I didn't intend to use python3. To fix this, I must manually edit Makefile as follows before running `make`.

{{{
-VIRTUALENV = virtualenv
+VIRTUALENV = virtualenv2
}}}

Some options for how to deal with this come to mind.

Does `./configure` support interactive configuration? If so, we could consider searching for all `virtualenv`s and then asking the user which one they want to use.

The undocumented `--with-virtualenv` switch [1] could be extended to accept a path to the desired executable.

If distributions consistently use `virtualenv2` for python2 and use `virtualenv` (or `virtualenv3`) exclusively for python3, perhaps we could tie the selection of `virtualenv` to the python version specified in configuration.

[1] `--with-virtualenv` is a programmed option in `./configure`, but it isn't shown in `./configure --help`. See issue #5022."	defect	new	trivial		programming		virtualenv,configure