[Python-Dev] repeated keyword arguments (original) (raw)

Guido van Rossum guido at python.org
Sat Jun 28 17:38:41 CEST 2008

On Sat, Jun 28, 2008 at 1:30 AM, tomer filiba <tomerfiliba at gmail.com> wrote:

On Jun 28, 12:56 am, "Guido van Rossum" <gu... at python.org> wrote:

No, it could just be a harmless typo in a long argument list. to elaborate on this point a little, i came across this error when i ported my code to 2.4. i used the optparse class which takes 10's of kwargs, and it turned out i'd given the same parameter twice (the infamous copy-paste problem). so on the one hand, it was a harmless typo (because the latest instance was taken). on the other hand, it's a good thing i tested it on 2.4, or i'd never notice the repeated argument, which may have led to weird runtime errors (if the order of the params was changed). i'd be in favor of fixing this in 2.5, just to eliminate possibly hard- to-debug runtime errors. since it's a syntax error, it would be early- noticed when the code is first run/imported, and it wouldn't require the original author of the code to fix.

But your anecdote is exactly why I don't want it fixed in 2.5. Your code was working, the typo was harmless. I don't want upgrades from 2.5.2 to 2.5.3 (or any x.y.z to x.y.(z+1)) to break code that was working before the upgrade! This is a principle we've adopted for such point-point upgrades for a long time. Also note that it took a long time before this was first reported, so it's not exactly like it's an important or frequent problem.

-- --Guido van Rossum (home page: http://www.python.org/~guido/)

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