[Python-Dev] Add a developer mode to Python: -X dev command line option

[Antoine Pitrou]

Le 16/11/2017 à 13:38, Victor Stinner a écrit :
> 2017-11-16 13:09 GMT+01:00 Antoine Pitrou <solipsis at pitrou.net>:
>>> What do you think? Is it ok to include asyncio in the global "developer mode"?
>>
>> I'd rather not.  Those are two orthogonal things.  In particular,
>> asyncio debug mode is quite expensive.
> 
> Is it really an issue? When you develop an application, the
> performance of the application shouldn't be an issue no?

When you develop an application, you can run functional tests which have
timing requirements (or simply be too annoying to run if runtimes are
multiplied by 2 or more).  In that case it is good to enable "cheap"
debug checks (those that have less than a 20% cost) while leaving the
expensive ones disabled.

> About asyncio debug mode, if it's too expensive to be used to develop
> an application, maybe there is an issue with additional checks? Should
> we remove some of them to be able to use asyncio debug mode in more
> cases?

Well, I'm sure some people like them, otherwise they wouldn't have been
added to the codebase in the first place :-)  For example, knowing where
a Future was created can make debug logs much more informative.

(see https://bugs.python.org/issue31970)

Regards

Antoine.