Re: [PATCH] docs: Makefile: Inherit PYTHONPYCACHEPREFIX setting as env variable

[Mauro Carvalho Chehab <mchehab+huawei@kernel.org>]

Em Thu, 1 May 2025 17:21:07 +0900
Akira Yokosawa <akiyks@gmail.com> escreveu:

> Commit 6c2f0b28d76e ("docs: Makefile: store __pycache__ at the output
> directory") assigns a new path to PYTHONPYCACHEPREFIX for building
> kernel documentation.
> 
> However, it is not necessarily optimal for everyone.
> 
> If you find PYTHONPYCACHEPREFIX is already set, it strongly suggests
> that the developer has selected the setting as best suited for one's own
> workflow.
> 
> Use "?=" in the assignment to PYTHONPYCACHEPREFIX so that the path of
> $(abspath $(BUILDDIR)/__pycache__) works only as a safeguard.
> 
> Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
> Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Sorry for not answering it earlier... I took a quick vacation last week
to rest after a long trip abroad.

It is a little late for that, as Jon already applied, but the change
looks good to me:

Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

> ---
> Mauro,
> 
> I left other Makefiles commit 5c5c32d7abd9 ("scripts/kernel-doc.py:
> don't create *.pyc files") has touched, as I'm not sure which path to
> assign in them.

Well, O= sets some environment var, but granted it requires some time
to understand kernel Makefiles and see where exactly it stores the
dest directory. I won't have any time this week or the next one to
check it, but I can try to write a patch for that later on, if nobody
does that before.

> Additional Notes:
> 
> Python's default behavior, which is safe in cases where the source tree
> is never shared heterogeneously, can be restored by defining it empty
> by saying:
> 
>     export PYTHONPYCACHEPREFIX=
> 
> As the path in the env var can have white spaces, a quote pair is added
> to make it a single token.

Perhaps it makes sense to place it somewhere at the documentation.

Regards,
Mauro

> 
> Thanks,
> Akira
> --
>  Documentation/Makefile | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/Makefile b/Documentation/Makefile
> index 59e95ebae786..d30d66ddf1ad 100644
> --- a/Documentation/Makefile
> +++ b/Documentation/Makefile
> @@ -82,9 +82,11 @@ loop_cmd = $(echo-cmd) $(cmd_$(1)) || exit;
>  # $5 reST source folder relative to $(src),
>  #    e.g. "userspace-api/media" for the linux-tv book-set at ./Documentation/userspace-api/media
>  
> +PYTHONPYCACHEPREFIX ?= $(abspath $(BUILDDIR)/__pycache__)
> +
>  quiet_cmd_sphinx = SPHINX  $@ --> file://$(abspath $(BUILDDIR)/$3/$4)
>        cmd_sphinx = $(MAKE) BUILDDIR=$(abspath $(BUILDDIR)) $(build)=Documentation/userspace-api/media $2 && \
> -	PYTHONPYCACHEPREFIX=$(abspath $(BUILDDIR)/__pycache__) \
> +	PYTHONPYCACHEPREFIX="$(PYTHONPYCACHEPREFIX)" \
>  	BUILDDIR=$(abspath $(BUILDDIR)) SPHINX_CONF=$(abspath $(src)/$5/$(SPHINX_CONF)) \
>  	$(PYTHON3) $(srctree)/scripts/jobserver-exec \
>  	$(CONFIG_SHELL) $(srctree)/Documentation/sphinx/parallel-wrapper.sh \
> 
> base-commit: c0fe189b590c754f69e0cb87c5b5674cad535cf6