[Python-Dev] RE: Ill-defined encoding for CP875?

[Tim Peters]

[M.-A. Lemburg]
> ...
> The "right" thing to do here, is to simply remove cp875
> from the test for round-tripping.

I'm relieved you think so, since that's what I already did <wink>.

> It is not the only encoding which fails this test, but it's not
> our fault: the codecs were all generated from the original codec
> maps at the Unicode.org site.
>
> If their mappings are broken, we can't do much about it... other
> than to ignore the error or remove the codec altogether.

On general principle I don't like either of those -- "in the face of
ambiguity, refuse the temptation to guess".  It's at least surprising to see

>>> unicode("?", "cp875").encode("cp875")
'\xfd'
>>>

now, yes?  Would it be better if an ambiguous encoding raised an exception in
"strict" mode?  That is, a third choice is to alert users when they're
relying on a broken part of a mapping.