[Python-Dev] Thoughts on running Python 3.5 on Windows (path, pip install --user, etc)

[Paul Moore]

I just thought I'd give installing Python 3.5 a go on my PC, now that
3.5a2 has come out. I didn't get very far (see earlier message) but it
prompted me to think about how I'd use it, and what habits I'd need to
change.

I'd suggest that the "what's new in 3.5" document probably needs a
section on the new installer that explains this stuff...

First of all, I always use "all users" installs, so I have Python in
"Program Files" now. As a result, doing "pip install foo" requires
elevation. As that's a PITA, I probably need to switch to using "pip
install --user". All that's fine, and from there "py -3.5" works fine,
as does "py -3.5 -m foo". But even if it is, not every entry point has
a corresponding "-m" invocation (pygments' pygmentize command doesn't
seem to, for example)

But suppose I want to put Python 3.5 on my PATH. The installer has an
"add Python to PATH" checkbox, but (if I'm reading the WiX source
right, I didn't select that on install) that doesn't add the user
directory. So I need to add that to my PATH. Is that right? And of
course, that means I need to *know* the user site directory
($env:LOCALAPPDATA\Python\Python35\Scripts), correct?

It feels to me like this might be a frustrating step backwards for
Windows users who have recently (with the arrival of ensurepip) got to
the point where they can just run Python with "Add to path" and then
simply do

    pip install pygments
    pygmentize --help

Maybe the answer is that we simply start recommending that everyone on
Windows uses per-user installs. It makes little difference to me
(beyond the fact that when I want to look at the source of something
in the stdlib, the location of the file is a lot harder to remember
than C:\Apps\Python34\Lib\whatever.py) but I doubt it's what most
people will expect.

I'm completely OK with the idea that we move to "Program Files" as a
default location. And I have no real issue with Steve's position that
the "Add to Path" option has issues that can't really be solved
because of the way Windows constructs the PATH. But I know there have
been a lot of people frustrated by the complicated instructions needed
to get something like pygmentize working, for whom getting pip in 2.7
and 3.4 was a major improvement. So I think we need *some*
documentation helping them deal with what could well seem like a step
backwards in Python 3.5...

If I knew what the best (recommended) answer was, I'd be happy to
write it up. But I'm not sure I do (after all, the target audience is
people for whom "Add C:\PythonXY\Scripts to your PATH" was a problem
in the pre-3.4 days).

Should I raise this as a bug against the 3.5 documentation? If so,
should it be a release blocker for the final release?

Paul