Re: [PATCH] submodule--helper: avoid use of %zu for now

> Since d7d850e2b9 (CodingGuidelines: mention C99 features we can't
> use, 2022-10-10), our CodingGuidelines document has explicitly
> forbidden the use of '%z' and '%zu' printf() format specifiers,
> even though C99 does support them.  However, a new instance crept
> in via 82c36fa0a9 (submodule: hash the submodule name for the
> gitdir path, 2026-01-12).
>
> We could claim that this is an unintentional weather balloon that
> nobody has complained about for the past six months since Git 2.54,
> proving that it is now safe to use these format specifiers.  But
> (1) it is probably too early to make that claim, as distributions
> often stick to a stale version for several releases, and (2) it is
> unlikely that a failure in this code path would manifest as a
> major user-visible breakage that would trigger a failure report to
> percolate down to us.
>
> Instead, let's stick to the established workaround recommended by
> our CodingGuidelines, which is to cast the value to (uintmax_t) and
> format it with PRIuMAX, at least for now.  Even if we eventually
> perform a bulk update using a Coccinelle script to transition to %z
> and %zu in the future, adding one more instance to the pile that
> will need such a conversion is hardly a tragedy.
>
> Signed-off-by: Junio C Hamano <gitster@pobox.com>
> ---
>  builtin/submodule--helper.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git i/builtin/submodule--helper.c w/builtin/submodule--helper.c
> index 1cc82a134d..92e38106c1 100644
> --- i/builtin/submodule--helper.c
> +++ w/builtin/submodule--helper.c
> @@ -549,7 +549,8 @@ static void create_default_gitdir_config(const char *submodule_name)
>  	}
>  
>  	/* Case 2.4: If all the above failed, try a hash of the name as a last resort */
> -	header_len = snprintf(header, sizeof(header), "blob %zu", strlen(submodule_name));
> +	header_len = snprintf(header, sizeof(header),
> +			      "blob %"PRIuMAX, (uintmax_t)strlen(submodule_name));
>  	the_hash_algo->init_fn(&ctx);
>  	the_hash_algo->update_fn(&ctx, header, header_len);
>  	the_hash_algo->update_fn(&ctx, "\0", 1);