[PATCH 4/4] rev-parse: avoid writing to const string for parent marks
- From
Jeff King <peff@peff.net>
- Date
- Mar 26, 2026, 19:14 UTC
- Message-ID
- <20260326191424.GD415796@coredump.intra.peff.net>
- In-Reply-To
- <20260326190243.GA412983@coredump.intra.peff.net>
The previous commit cleared up some const confusion in handling parent marks in revision.c, but we have roughly the same code duplicated in rev-parse. This one is much easier to fix, because the handling of the shortened string is all done in one place, after detecting any marks (but without shortening the string between marks).
As a side note, I suspect this means that it behaves differently than the revision.c parser for weird stuff like "foo^!^@^-", but that is outside the scope of this patch.
While we are here, let's also rename the variable "dotdot", which is totally misleading (and which we already fixed in revision.c long ago via f632dedd8d (handle_revision_arg: stop using "dotdot" as a generic pointer, 2017-05-19)).
Doing that here makes the diff a little messier, but it also lets the compiler help us make sure we did not miss any stray mentions of the variable while we are changing its semantics.
Signed-off-by: Jeff King <peff@peff.net> --- builtin/rev-parse.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-)
diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c index 5da9537113..218b5f34d6 100644 --- a/builtin/rev-parse.c +++ b/builtin/rev-parse.c @@ -326,46 +326,47 @@ static int try_difference(const char *arg) static int try_parent_shorthands(const char *arg) { - char *dotdot; + const char *mark; struct object_id oid; struct commit *commit; struct commit_list *parents; int parent_number; int include_rev = 0; int include_parents = 0; int exclude_parent = 0; + char *to_free; - if ((dotdot = strstr(arg, "^!"))) { + if ((mark = strstr(arg, "^!"))) { include_rev = 1; - if (dotdot[2]) + if (mark[2]) return 0; - } else if ((dotdot = strstr(arg, "^@"))) { + } else if ((mark = strstr(arg, "^@"))) { include_parents = 1; - if (dotdot[2]) + if (mark[2]) return 0; - } else if ((dotdot = strstr(arg, "^-"))) { + } else if ((mark = strstr(arg, "^-"))) { include_rev = 1; exclude_parent = 1; - if (dotdot[2]) { + if (mark[2]) { char *end; - exclude_parent = strtoul(dotdot + 2, &end, 10); + exclude_parent = strtoul(mark + 2, &end, 10); if (*end != '\0' || !exclude_parent) return 0; } } else return 0; - *dotdot = 0; + arg = to_free = xmemdupz(arg, mark - arg); if (repo_get_oid_committish(the_repository, arg, &oid) || !(commit = lookup_commit_reference(the_repository, &oid))) { - *dotdot = '^'; + free(to_free); return 0; } if (exclude_parent && exclude_parent > commit_list_count(commit->parents)) { - *dotdot = '^'; + free(to_free); return 0; } @@ -386,7 +387,7 @@ static int try_parent_shorthands(const char *arg) free(name); } - *dotdot = '^'; + free(to_free); return 1; }
-- 2.53.0.1081.gf77a8b8145