Re: [PATCH 5/6] do not discard const: keep signature

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 26, 2026, 17:18 UTC
Message-ID: <xmqqbjgaqzk3.fsf@gitster.g>
In-Reply-To: <9a90f93111ec54e5eb9675cb84ac1d70ad95e118.1774537954.git.git@grubix.eu>

Michael J Gruber <git@grubix.eu> writes:

> Here, while we do not mutate the struct itself, many other signatures
> expect a non-const argument - possibly unnecessarily - so we opt to keep
> the original signature by casting to non-const.
> ---

Sorry, but I do not understand the above description, or the code change. Doesn't bsearch() returns non-const "void *" pointer?

Ah, the constness of the return value in C23 depends on the constness of pm->commits[] array, which inherits its constness from the constness of parameter pm to the function, and you cast the value we are going to return explicitly to a non-const pointer.

OK. In the context of "C23 constness" patch series, that may be obvious to you, but I suspect a future reader who finds this single commit from the output of "git blame" or something would be puzzled unless we say this is about adjusting to C23 that makes bsearch() a qualifier-preserving function somewhere in the log message.

Show 15 quoted lines

>  pseudo-merge.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/pseudo-merge.c b/pseudo-merge.c
> index a2d5bd85f9..ac81792e65 100644
> --- a/pseudo-merge.c
> +++ b/pseudo-merge.c
> @@ -644,7 +644,7 @@ static struct pseudo_merge_commit *find_pseudo_merge(const struct pseudo_merge_m
>  	if (!pm->commits_nr)
>  		return NULL;
>  
> -	return bsearch(&pos, pm->commits, pm->commits_nr,
> +	return (struct pseudo_merge_commit *) bsearch(&pos, pm->commits, pm->commits_nr,
>  		       PSEUDO_MERGE_COMMIT_RAWSZ, pseudo_merge_commit_cmp);
>  }