[Distutils] desirability of multiple, divergent Python instances

[Ben Finney]

Stephen Waterbury <waterbug at pangalactic.us> writes:

> Ben Finney wrote:
> > It's my position that the Python instance one uses for development
> > should diverge as little as possible from the default system
> > instance. Otherwise one is actively pursuing a recipe for
> > dependency failures when one eventually deploys the result.
> 
> > [...]
> > Help me understand, please.
> 
> Have you read my proposal?

I'd read it, yes. Thanks for bringing it explicitly back into the
thread.

> My main motivation in proposing it is to give the user complete
> control over the Python environment that is in their path -- which
> is not easy to do on Debian/Ubuntu at the moment

This is a laudable goal. It is met, for just about every other
user-configurable application, by allowing user-specific *overrides*
to the defaults to be set in configuration files.

> by giving the Python utilities and packages that OS-related
> functions depend on a completely insular Python environment that the
> OS can manage however it sees fit. In my view, both as a developer
> and a user, but especially as a developer, it would make life
> easier.

I can't see how you come to this conclusion. Surely one wants the
possibility of divergence from the default to be explicit and easily
discoverable? This is entirely lost if the only assumption that can be
made is "the entire Python environment has been replicated and utterly
isolated from the system default Python".

Stephen Waterbury <waterbug at pangalactic.us> writes:

> "system Python" -- the Python (and its site-pkgs, etc.) that any
> Python scripts used by the OS depend on, which would of course by
> solely determined by the OS.
> 
> This would be distinct, in my proposal, from any packages named
> "python" or "python.x" in the package namespace of the system
> package manager (e.g. apt).

It seems clear to me that divergence between these two should be kept
to a minimum; and that such divergence is best minimalised if they are
*the same instance*, merely operating under explicit customisation
for each use that needs it.

-- 
 \         "Pinky, are you pondering what I'm pondering?" "I think so, |
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Ben Finney