Re: [PATCH] checkout: fix BUG() case in 9081a421a6
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Jan 22, 2022, 00:33 UTC
- Message-ID
- <xmqqr190d2xg.fsf@gitster.g>
- In-Reply-To
- <patch-1.1-21ddf7c628d-20220120T212233Z-avarab@gmail.com>
Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:
Show 20 quoted lines
> diff --git a/builtin/checkout.c b/builtin/checkout.c
> index 6a5dd2a2a22..52a47ef40e1 100644
> --- a/builtin/checkout.c
> +++ b/builtin/checkout.c
> @@ -1090,13 +1090,10 @@ static int switch_branches(const struct checkout_opts *opts,
> FREE_AND_NULL(old_branch_info.path);
>
> if (old_branch_info.path) {
> - const char *const prefix = "refs/heads/";
> - const char *p;
> - if (skip_prefix(old_branch_info.path, prefix, &p))
> - old_branch_info.name = xstrdup(p);
> - else
> - BUG("should be able to skip past '%s' in '%s'!",
> - prefix, old_branch_info.path);
> + const char *p = old_branch_info.path;
> +
> + skip_prefix(old_branch_info.path, "refs/heads/", &p);
> + old_branch_info.name = xstrdup(p);
> }What we want is a faithful reversion wrt the behaviour, while keeping the leakfix.
The old code did
skip_prefix(old_branch_info.path, "refs/heads", &old_branch_info.name);
meaning that old_branch_info.name is left unchanged if .path did not begin with "refs/heads".
The function that uses old_branch_info.name prepared at this point in the flow is merge_working_tree(), where it uses .name for the textual label for the "ancestor" tree. It is preferrable to have a branch name, but the code is prepared to see NULL in there, where it comes up with an abbreviated commit object name.
o.ancestor = old_branch_info->name;
if (old_branch_info->name == NULL) {
strbuf_add_unique_abbrev(&old_commit_shortname,
&old_branch_info->commit->object.oid,
DEFAULT_ABBREV);
o.ancestor = old_commit_shortname.buf;
}As 9081a421a6 properly 0-initializes old_branch_info, I think it is sufficient to just drop the "else BUG" clause; we shouldn't have to copy the .path that does not begin with "refs/heads/" there; .name member would be NULL in such a case.
I do not care too much about reverting the constant that is only used once into a literal. So, how about doing it this way instead?
builtin/checkout.c | 3 --- 1 file changed, 3 deletions(-)
diff --git i/builtin/checkout.c w/builtin/checkout.c index 43d0275187..1fb34d537d 100644 --- i/builtin/checkout.c +++ w/builtin/checkout.c @@ -1094,9 +1094,6 @@ static int switch_branches(const struct checkout_opts *opts, const char *p; if (skip_prefix(old_branch_info.path, prefix, &p)) old_branch_info.name = xstrdup(p); - else - BUG("should be able to skip past '%s' in '%s'!", - prefix, old_branch_info.path); } if (opts->new_orphan_branch && opts->orphan_from_empty_tree) {