[Python-Dev] New Windows installer for Python 3.5

Chris Angelico rosuav at gmail.com
Mon Jan 5 01:19:37 CET 2015

On Mon, Jan 5, 2015 at 9:56 AM, Steve Dower <Steve.Dower at microsoft.com> wrote:
> (Windows will always put per-user PATH entries at the end). The py.exe launcher handles this best, and the system version will always be found first.
> As for versions, 3.5 vs 3.6 should be distinguished explicitly ("py -3.5" vs "py -3.6") and 3.5.0 vs 3.5.1 can only be installed at the same time if one is system-wide and the other is per-user. In this case, the per-user one will be used by py.exe, even if it is older than the system-wide one.

Wait, what?</anna>

If I'm reading this correctly, PATH is set such that an all-users
version trumps a self-only version, but when you use the py.exe
launcher, it's the other way around? That seems extremely confusing.
But if that's not a deliberate design decision and isn't enforced by
external code, would it be possible to simply invert that for PATH,
and have a per-user installation always be found ahead of a
system-wide one? That would make reasonable sense, if it can be done.

> Incidentally, whoever came up with the py.exe launcher deserves a medal. It's made dealing with multiple versions amazingly easy.

https://www.python.org/dev/peps/pep-0397/ - and I agree :)


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