Re: [PATCH] Updates Documentation/Makefile to use Python3 as fallback

[Jonathan Corbet]

Noa Sakurajin <noasakurajin@xxxxxx> writes:

[CC += kbuild maintainers]

>  Before the command python was needed for the documentation to build.
>  This patch checks if python is available and uses python3 as
>  fallback.
>
>  This is needed because a lot of distribution (at least Ubuntu)
>  only provide python3 and not python. scripts/sphinx-pre-install
>  checks for python3 first and does not check if python exists
>  which causes it to report that everything is installed even
>  if the documentation build failed.
>
> Signed-off-by: Noa Sakurajin <noasakurajin@xxxxxx>
> ---
>  Documentation/Makefile | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/Makefile b/Documentation/Makefile
> index 61a7310b49e0..8a4a7df3b74a 100644
> --- a/Documentation/Makefile
> +++ b/Documentation/Makefile
> @@ -75,7 +75,8 @@ quiet_cmd_sphinx = SPHINX  $@ --> file://$(abspath $(BUILDDIR)/$3/$4)
>        cmd_sphinx = $(MAKE) BUILDDIR=$(abspath $(BUILDDIR)) $(build)=Documentation/userspace-api/media $2 && \
>  	PYTHONDONTWRITEBYTECODE=1 \
>  	BUILDDIR=$(abspath $(BUILDDIR)) SPHINX_CONF=$(abspath $(srctree)/$(src)/$5/$(SPHINX_CONF)) \
> -	$(PYTHON) $(srctree)/scripts/jobserver-exec \
> +	PY=$(shell command -v $(PYTHON) 2> /dev/null) \
> +	$${PY:-"$(PYTHON3)"} $(srctree)/scripts/jobserver-exec \

So I see what you're trying to do, and we definitely want this to work.
I susped this isn't the right fix, though; it could leave us open to
similar issues elsewhere in the tree.

Personally, I think that $(PYTHON) should get a working Python if it's
installed, so I would suggest fixing the top-level Makefile to set it
correctly.  Masahiro, thoughts on that?

Alternatively, we could just say $(PYTHON3) and explicitly leave Python2
behind; that needs to happen in the not-too-distant future regardless
but we haven't decided to actually do it yet.

Thanks,

jon