Re: [PATCH] git-compat-util.h: GCC deprecated message arg only in GCC 4.5+

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

On Wed, Oct 05 2022, Aleajndro R Sedeño wrote:

> From: Alejandro R. Sedeño <asedeno@mit.edu>
>
> From: https://gcc.gnu.org/gcc-4.5/changes.html
>
>> The deprecated attribute now takes an optional string argument, for
>> example, __attribute__((deprecated("text string"))), that will be
>> printed together with the deprecation warning.
>
> While GCC 4.5 is already 12 years old, git checks for even older
> versions in places. Let's not needlessly break older compilers when
> a small and simple fix is readily available.
>
> Signed-off-by: Alejandro R. Sedeño <asedeno@mit.edu>
> Signed-off-by: Alejandro R Sedeño <asedeno@google.com>
> ---
>  git-compat-util.h | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/git-compat-util.h b/git-compat-util.h
> index b90b64718e..045b47f83a 100644
> --- a/git-compat-util.h
> +++ b/git-compat-util.h
> @@ -189,9 +189,12 @@ struct strbuf;
>  #define _NETBSD_SOURCE 1
>  #define _SGI_SOURCE 1
>  
> -#if defined(__GNUC__)
> +#if GIT_GNUC_PREREQ(4, 5)
>  #define UNUSED __attribute__((unused)) \
>  	__attribute__((deprecated ("parameter declared as UNUSED")))
> +#elif defined(__GNUC__)
> +#define UNUSED __attribute__((unused)) \
> +	__attribute__((deprecated))
>  #else
>  #define UNUSED
>  #endif

This LGTM, thanks a lot for that fix & fixing this (minor) breakage of
mine.

I did test on an older GCC myself, and then (in lieu of logging into an
ancient system I have access to) scoured the release notes of gcc, and
discovered that "deprecated" was older than anything we cared about.

But I obviously missed that while the feature had been there for a
longer time, it didn't take this parameter until GCC 4.5, sorry!