Subject: Re: [PATCH v3 2/3] sequencer: don't use die_errno() on refs_resolve_ref_unsafe() failure

From: Junio C Hamano <[email-masked]>
Date: Wed, 12 Jan 2022 12:02:50 -0800

Ævar Arnfjörð Bjarmason  <[email-masked]> writes:

> Change code that was faithfully migrated to the new "resolve_errno"
> API in ed90f04155d (refs API: make resolve_ref_unsafe() not set errno,
> 2021-10-16) to stop caring about the errno at all.
>
> When we fail to resolve "HEAD" after the sequencer runs it doesn't
> really help to say what the "errno" value is, since the fake backend
> errno may or may not reflect anything real about the state of the
> ".git/HEAD". With the upcoming reftable backend this fakery will
> become even more pronounced.

OK.  In principle I agree with the reasoning.  Perhaps it can be
better done as a preparation for the reftable backend in future
cycles, not now.

> So let's just die() instead of die_errno() here. This will also help
> simplify the refs_resolve_ref_unsafe() API. This was the only user of
> it that wasn't ignoring the "failure_errno" output parameter.

> Signed-off-by: Ævar Arnfjörð Bjarmason <[email-masked]>
> ---
>  sequencer.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/sequencer.c b/sequencer.c
> index 6abd72160cc..03cdf548d72 100644
> --- a/sequencer.c
> +++ b/sequencer.c
> @@ -1281,7 +1281,7 @@ void print_commit_summary(struct repository *r,
>  	struct strbuf author_ident = STRBUF_INIT;
>  	struct strbuf committer_ident = STRBUF_INIT;
>  	struct ref_store *refs;
> -	int resolve_errno;
> +	int ignore_errno;
>  
>  	commit = lookup_commit(r, oid);
>  	if (!commit)
> @@ -1333,11 +1333,9 @@ void print_commit_summary(struct repository *r,
>  
>  	refs = get_main_ref_store(the_repository);
>  	head = refs_resolve_ref_unsafe(refs, "HEAD", 0, NULL, NULL,
> -				       &resolve_errno);
> -	if (!head) {
> -		errno = resolve_errno;
> -		die_errno(_("unable to resolve HEAD after creating commit"));
> -	}
> +				       &ignore_errno);
> +	if (!head)
> +		die(_("unable to resolve HEAD after creating commit"));
>  	if (!strcmp(head, "HEAD"))
>  		head = _("detached HEAD");
>  	else