On 5/29/2018 6:06 AM, Petr Viktorin wrote:
Python 3.7 removes the undocumented internal import `os.errno`.
Among a couple of hundred others, including some from idlelib.
We consider that a an implementation detail, which can be changed
*without notice* even in a bugfix release.
We core developers occasionally run a linter on our code, or someone
does it for us. Those of us who like clean code attend to warnings such
as 'unused import'. I removed a couple of idlelib inports because of
someone else running flake8.
Projects that depend on it are incorrect and should be fixed.
I think we can agree that better warning of 'use of stdlib internal
import' would be great.
On bpo-33666, there's a debate on whether the removal should be
mentioned in release notes, on the grounds that it broke some projects,
is used in quire a few tutorials/books/examples, and it's been working
since Python 2.5 or so.
Since I agree that *this* removal may possibly have the greatest impact,
and that the purpose of What's New is to help users, I am glad Guido
spoke up to say 'do it'. See my reponse to his post for a suggested entry.
But here's the thing: the more I think about this, the less I consider
`os.errno` as "undocumented". Here's what I consider a reasonable path a
programmer might go through:
# Where do I find errno values?
# Maybe it's in `os`, like all other basic platform bindings?
>>> import os
>>> os.err<tab>
os.errno os.error(
>>> help(os.errno)
Help on built-in module errno:
...
# Yup, There it is!
Suppose a naive beginner who confuses 'IDLE' with 'python' (they exist!)
thinks "Where can I find re functions? How about 'pyshell'
>>> import idlelib.pyshell as ps
>>> ps.<completion box>r<jumps to re><return>
<module 're' from 'C:\\Programs\\Python37\\lib\\re.py'>
>>> help(ps.re)
Help on module re:
!
Is that reasoning sound?
Do you claim that os.errno is more documented (by the 'official' docs
and help) than idlelib.pyshell.re?
--
Terry Jan Reedy
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