[issue31975] Add a default filter for DeprecationWarning in __main__

[Nick Coghlan]

Nick Coghlan <ncoghlan at gmail.com> added the comment:

Reviewing the original thread yet again, you're right the original decision wasn't specifically about developer tools (and I guess at some level I knew that, or I wouldn't have been motivated to suggest the change to FutureWarning's documented purpose).

That said, I consider noise from developer tools to be the most compelling example as:

1. Running them from the command line is their normal mode of use (unlike GUI apps which often have no visible console, implicitly silencing all warnings anyway)
2. It's routine for Python developers to run their developer tools on the latest version of Python, whereas regular applications are more likely to be pre-tested against a particular Python version these days
3. Mixing up warnings from a tool like pylint or mypy about the code it is analysing with deprecation warnings about pylint's own code is clearly going to be unhelpful and confusing, no matter how you feel about deprecation warnings in the general case

All the points that are most debatable for regular apps ("Do they even have a console?", "Why are end users supplying their own Python version?", "Why can't they just ignore the error?") have clear answers in the developer tools case that favour leaving deprecation warnings off by default.

----------

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue31975>
_______________________________________