Python version coexistence on WIndows

[David Bolen]

"Tim Peters" <tim at zope.com> writes:

> The most obvious way is for you to-- just like you do on Unix --stay away
> from doing anything on Windows that *relies* on registry settings.  The core
> PythonLabs Windows distribution makes no use of the registry for normal
> operation, so if you're doing something that does need registry info, that's
> not our fault <wink>.

Right - and I've found the only real conflict with multiple versions
in the registry is with file extension registration - where the most
recent version of Python I've installed "wins".  That only comes into
play if you let Windows pick your Python interpreter - you can always
explicitly run a specific Python version against a script.  In the
end, I typically just edit the file associations to make them default
to the version I want as the default.

Since everything else is under a version specific Python tag in the
registry (or in the start menu), even with the default registry
adjusting installers, I've got 1.5.2, 2.0.1, 2.1.1 and 2.2a1 installed
simultaneously without any problems.  Note that multiple revisions of
the same version (e.g., 2.2a1 and any future 2.2a2 for example) will
have other conflicts as they use the same keys which are only major.minor.

The win32all extensions do really seem to need the registry (at the
least to find some magic modules), but they are also versioned (so the
DLLs don't conflict in the system directory) and installed beneath the
appropriate Python key for the version of the extensions, so I haven't
had any problem with them either.

I run most stuff with Cygwin/bash, so I have a few bash aliases that
run the right interpreter against a script when I want to pick
explicitly, and some others that temporarily adjust paths to default
to the right installation directories.  The same could be done with
.cmd files (or .bat files).

--
-- David
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