Re: [OE-core] bitbake-server does not exit after build ends

["Böszörményi Zoltán" <zboszor@gmail.com>]

2023. 11. 28. 11:00 keltezéssel, Richard Purdie írta:
> On Tue, 2023-11-28 at 10:26 +0100, Böszörményi Zoltán wrote:
>> So it's not just Fedora, but Python 3.12 in general.
>>
>> Googling for problem with threads + fork reveals that
>> it is indeed an issue even in C / POSIX: only the thread
>> executing fork() will become part of the new process,
>> but not the main process starting the thread or any
>> other threads from the original process.
>>
>> The warning is justified, and apparently the issue
>> not occurring in bitbake with previous Python versions
>> is pure luck.
> I'm not sure that is entirely true/fair.

Maybe not fair. Still, true. See this piece:

http://www.doublersolutions.com/docs/dce/osfdocs/htmls/develop/appdev/Appde193.htm

Other discussions, like this one confirm the same:
https://stackoverflow.com/questions/39890363/what-happens-when-a-thread-forks

>   The way bitbake has executed
> processes and handled threads was very carefully written deliberately
> to avoid some of these kinds of issues so it wasn't "pure luck". What I
> don't know is what changed in 3.12 to mean this now is potentially
> breaking.

The warning only occurs if os.fork() is called when
there are already Python threads.

I guess the general performance uplift in Python 3.12
can trigger a pre-existing issue in bitbake more easily.

It is entirely possible that the threads bitbake creates do not
exist yet with Python 3.11 and earlier at the time of executing
os.fork(). ¯\_(ツ)_/¯