[Python-Dev] Python install layout and the PATH on win32 (original) (raw)

Paul Moore p.f.moore at gmail.com
Sat Mar 17 12:57:00 CET 2012

On 17 March 2012 05:28, Mark Hammond <skippy.hammond at gmail.com> wrote:

I hate to seem like I'm piling on now after panning your last brainstorm :-), but... this would be quite problematic for virtualenv users, many of whom do rely on the fact that the virtualenv "stuff" is confined to within a limited set of known subdirectories, and they can overlay a virtualenv and their own project code with just a few virtualenv directories vcs-ignored.

I would prefer either the status quo or the proposed cross-platform harmonization.

I work purely Windows-only, and I have a few scripts that manage virtualenvs for myself (for example, sort of a personal virtalenv-wrapper for Powershell - see https://bitbucket.org/pmoore/poshpy for a work-in-progress version). They have special casing for the differences in layout between standard installs, build directories, and virtualenvs. Changing the layout would cause these tools to need to change.

In theory, putting python.exe/pythonw.exe into "Scripts" would simplify them (no need to cater for the cases where I need to put 2 directories on PATH), and changing Scripts -> bin would be trivial. But in practice, it would mean that I need to check (somehow) the Python version and adjust the layout used accordingly. As there is no way of knowing the Python version without running Python, this is too slow to be practical.

So while the changes are in theory harmless in isolation (except the library locations - changing those would cause pain) the need to support multiple versions would make this a major issue for me.

So, I prefer the status quo. If necessary, I can live with the change to rename scripts as bin and put the Python executables in there (some cost, but some small benefit as well) but I oppose changing the library locations (all cost, no gain for me). All of this presupposes that both the standard installer and virtualenv change. I suspect that having virtualenv respect the old layout for 3.2 and earlier, and the new one for 3.3+, could be messy, though, so that's not guaranteed, I guess...

Breaking the few tools I'm concerned about vs asking Van etc to continue taking the pain he feels isn't going to mean the end of the world for any of us.

Agreed. I can't say my pain is any more important than Van's, but the same applies the other way round :-)

So given the stakes in this particular discussion aren't that high, I'll try and summarize the thread over the next few days (or someone can beat me to it if they prefer) and we can ask someone semi-impartial to make a decision.  I'd be happy to nominate MvL if he feels so inclined (even though I haven't asked him).

Sounds reasonable. I'd suggest that Van should probably report any other examples where someone would benefit from this change - at the moment unless I've misread the thread, it seems like he's the only example of someone who would gain.

Paul.

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