Hi,
2017-12-12 21:21 GMT+01:00 Guido van Rossum <guido@python.org>:
> I'm still hoping to accept this PEP, but I don't have time to wrap my head
> around -Xdev ("devmode"?) which appears to be Victor's latest pet project.
> Should PEP 565 be changed to copy with devmode's behavior, or the other way
> around, or should they just ignore each other? It is not clear of me what
> the status of the mention in PEP 565 of -Xdev is -- normative or
> informational? I really don't want to have to learn how devmode works in
> order to be able to accept PEP 565 (or send it back for revision), so I am
> asking you two to let me know.
The warnings filters had a few corner cases. We discussed with Nick to
fix them to make them simpler. We agreed on these priorities for
command line options and environment variables:
-b and -bb > -W > PYTHONWARNINGS > -X dev > default filters
In release mode, the default filters became:
ignore::DeprecationWarning
ignore::PendingDeprecationWarning ignore::ResourceWarning
ignore::ImportWarning
ignore::BytesWarning is gone. We now rely on the fact the BytesWarning
should not be emited without -b nor -bb in practice.
It has been implemented in https://bugs.python.org/issue32230 ! (I
just merged Nick's PR.)
Now -X dev behaves again as my initial propopal: for warnings, "-X
dev" simply behaves as "-W default". (Previously, I had to hack the
code to respect -b and -bb options, but I don't think that it's worth
it to explain that here, it's doesn't matter anymore ;-))
The PEP 565 is still different: it doesn't behaves as "-W default",
but "-W default::DeprecationWarning:__main__". Only DeprecationWarning
warnings are shown, whereas -X dev shows DeprecationWarning, but also
PendingDeprecationWarning, ResourceWarning and ImportWarning.
Moreover, -X dev shows warnings in all modules, not only __main__.
You may see -X dev as a builtin linter, whereas PEP 565 seems to be
very specific to one specific issue: display deprecation warnings, but
only in the __main__ module.
Does it help you to understand the difference?
Note: I still dislike the PEP 565, but well, that's just my opinion ;-)
Victor