Re: [PATCH] perf: python: Fix build when PYTHON_CONFIG is user supplied

From: Ian Rogers <irogers@google.com>
To: James Clark <james.clark@arm.com>
Cc: linux-perf-users@vger.kernel.org, acme@kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf: python: Fix build when PYTHON_CONFIG is user supplied
Date: Thu, 28 Jul 2022 09:37:32 -0700	[thread overview]
Message-ID: <CAP-5=fXnR=LSk-bO02V7HzWTTCrsbnM1w63_YYqSMEgy0vM-PQ@mail.gmail.com> (raw)
In-Reply-To: <20220728093946.1337642-1-james.clark@arm.com>

On Thu, Jul 28, 2022 at 2:40 AM James Clark <james.clark@arm.com> wrote:
>
> The previous change to Python autodetection had a small mistake where
> the auto value was used to determine the Python binary, rather than the
> user supplied value. The Python binary is only used for one part of the
> build process, rather than the final linking, so it was producing
> correct builds in most scenarios, especially when the auto detected
> value matched what the user wanted, or the system only had a valid set
> of Pythons.
>
> Change it so that the Python binary path is derived from either the
> PYTHON_CONFIG value or PYTHON value, depending on what is specified by
> the user. This was the original intention.
>
> This error was spotted in a build failure an odd cross compilation
> environment after commit 4c41cb46a732fe82 ("perf python: Prefer
> python3") was merged.
>
> Fixes: 630af16eee495f58 ("perf tools: Use Python devtools for version autodetection rather than runtime")
> Signed-off-by: James Clark <james.clark@arm.com>

Acked-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> ---
>  tools/perf/Makefile.config | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> index d3c254c0f5c6..a69da9f34486 100644
> --- a/tools/perf/Makefile.config
> +++ b/tools/perf/Makefile.config
> @@ -265,7 +265,7 @@ endif
>  # defined. get-executable-or-default fails with an error if the first argument is supplied but
>  # doesn't exist.
>  override PYTHON_CONFIG := $(call get-executable-or-default,PYTHON_CONFIG,$(PYTHON_AUTO))
> -override PYTHON := $(call get-executable-or-default,PYTHON,$(subst -config,,$(PYTHON_AUTO)))
> +override PYTHON := $(call get-executable-or-default,PYTHON,$(subst -config,,$(PYTHON_CONFIG)))
>
>  grep-libs  = $(filter -l%,$(1))
>  strip-libs  = $(filter-out -l%,$(1))
> --
> 2.28.0
>