[Buildroot] [PATCH] support/testing/run-tests: unbreak on Debian testing/unstable

[Peter Korsgaard]

>>>>> "Peter" == Peter Korsgaard <peter at korsgaard.com> writes:

 > Commit 3d2141bcee("support/testing/run-tests: specify multiprocessing
 > method") added a call to multiprocessing.set_start_method('fork') as a
 > workaround for python 3.14, which changed the default start method to
 > forkserver - Which is incompatible with the nose2 setup.

 > multiprocessing.set_start_method() is only supposed to be called a maximum
 > of 1 time per process and throws a RuntimeError if called more than that
 > (even with the same arguments):

 >>>> import multiprocessing
 >>>> multiprocessing.set_start_method('fork')
 >>>> multiprocessing.set_start_method('fork')
 > Traceback (most recent call last):
 >   File "<python-input-2>", line 1, in <module>
 >     multiprocessing.set_start_method('fork')
 >     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^
 >   File "/usr/lib/python3.13/multiprocessing/context.py", line 247, in set_start_method
 >     raise RuntimeError('context has already been set')

 > Debian included a similar patch in python3-nose2 0.51.1-2 (currently in
 > testing/unstable) which adds its own call to set_start_method():

 > https://salsa.debian.org/python-team/packages/nose2/-/blob/debian/0.15.1-2/debian/patches/0004-plugins-mp-set-context-to-fork-for-Python-3.14-mp-AP.patch?ref_type=tags

 > Which comes from:
 > https://github.com/nose-devs/nose2/pull/644

 > As discussed in the upstream PR, this is not a correct fix is wrong and
 > breaks various use cases.  An issue has been opened to get this fixed in the
 > Debian packaging at:

 > https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1129350

 > But until that is done, rework the patch to:

 > - Only override set_start_method() if needed to limit impact
 > - Monkey patch set_start_method() so additional calls are ignored

 > To unbreak run-test on affected Debian systems and add some documentation to
 > make it clear why this is done.

 > Signed-off-by: Peter Korsgaard <peter at korsgaard.com>

Committed after changing the logic to use the optional allow_none /
force arguments as pointed out by Julien, thanks.

-- 
Bye, Peter Korsgaard