[Python-Dev] Make stacklevel=2 by default in warnings.warn()

[Serhiy Storchaka]

On 21.09.15 20:00, Serhiy Storchaka wrote:
> On 21.09.15 10:18, Victor Stinner wrote:
>> ---
>> sys:1: UserWarning: here
>> ---
>>
>> "sys:1" is not really useful :-/
>
> This is not new. The same output we get when run a module that correctly
> emits a warning at module level (with explicit stacklevel=2).
>
> $ ./python -Wa Lib/imp.py
> sys:1: PendingDeprecationWarning: the imp module is deprecated in favour
> of importlib; see the module's documentation for alternative uses
>
> If this message looks confusing for you, we can avoid it if stop
> skipping frames further if frame.f_back is None. This will got rid of
> "sys:1:" in both cases, explicit and implicit stacklevel=2.

The patch is provided in http://bugs.python.org/issue25204.