[Python-Dev] Proposal to revert r54204 (splitext change)

Stephen Hansen apt.shansen at gmail.com
Thu Mar 15 22:28:26 CET 2007

> For example, I committed a fix for urllib that made it raise IOError
> instead
> of an AttributeError (which wasn't explicitly raised, of course) if a
> certain
> error condition occurs.
> This is changed behavior too, but if we are to postpone all these fixes
> to 3.0, we won't have half of the fixes in Python 2.6 that are there now.

There's a big difference between that change and this one; that change is
'loud'. It makes noise. It's raising an exception: that exception will
either be handled or will propagate up the stack and be noticed somewhere.

I *think* (ahem.. I read minds...) the problem people are having with this
particular change is the fact that the behavior of this function is being
changed in a way that is completely silent. Code written to expect one kind
of result are now getting a different kind of result... instead of having an
error thrown, a warning given, or something explicit... it's just different

And it'd be so easy to do it in a way which wouldn't be silent... just throw
out a warning, and defer the actual change until the next release.

Expecting people to keep on top of Misc/NEWS and re-read the documentation
for every function in their code is a tad unreasonable. I don't personally
find it unreasonable for people to ask for a bit more of an extended
migration path when changes that are being implemented will cause *silent*
changes in behavior.

It's been very hard for my company to move from 2.3 to 2.4 as a development
platform as it is, which we're just barely doing now... for this reason I'm
paying a lot more attention to -dev lately to be prepared for 2.6 and
beyond. Not everyone has the time to do that.. there's a lot of messages :)
And Misc/NEWS is *huge*. Warnings are a very useful mechanism for
semi-painless migrations and upgrades...

(And, if I thought it'd have any chance of going in, I'd submit a patch to
add a warning and adjust docs/tests/etc... but this issue seems ever so

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