[Python-Dev] python/dist/src/Lib/bsddb __init__.py,1.5,1.6

[Martin v. Löwis]

Michael Chermside <mcherm at mcherm.com> writes:

> I don't really understand this absolutist position. 

I think the rationale is that developers don't actively *use* bug
fixes, whereas they do use new features.

So when you tell them "we have booleans now", they will drop
everything else and start putting booleans all over the place. In the
middle of that, they think "wait, what about 2.2", and they will test
2.2.1, and find that it works just fine. They run into problems only
after they release the software.

With bug fixes, it is different: People won't actively change their
working code to deliberately formulate it in a way that breaks on
older Python versions. Instead, upon reading that the bug has been
fixed, they typically think "does not concern me", and proceed with
whatever they were doing, anyway. In some cases, they may happen to
write new code that relies on a recent bug fix. When they discover
that older versions don't work with their code, they just bump the
prerequisites, or add a work-around.

In addition, there is always the concern that new code may break
existing code, so the amount of new code should be kept to the
smallest possible minimum. Adding new features is beyond that minimum,
so it should not be done (regardless of whether that new code is
likely to break existing code, upon visual inspection).

Regards,
Martin