On Wed, Aug 13, 2025 at 02:19:14PM +0100, Phillip Wood wrote:
> I had a quick look at the callers of describe_commit() and they all seem to
> use an oid that they get from looking up a commit so I'm not sure under what
> circumstances this call to lookup_commit_reference() can fail.
I wonder if it would make sense for describe_commit() to just take a
"struct commit" pointer. Then it could skip the call to turn the oid
into a commit entirely, and the compiler would make sure we always have
a commit. :)
Something like this (totally untested, and not something I'm planning to
follow up on, but maybe inspirational):
diff --git a/builtin/describe.c b/builtin/describe.c
index 32f5bf513f..3e8691a4c4 100644
--- a/builtin/describe.c
+++ b/builtin/describe.c
@@ -352,26 +352,24 @@ static void append_suffix(int depth, const struct object_id *oid, struct strbuf
repo_find_unique_abbrev(the_repository, oid, abbrev));
}
-static void describe_commit(struct object_id *oid, struct strbuf *dst)
+static void describe_commit(struct commit *cmit, struct strbuf *dst)
{
- struct commit *cmit, *gave_up_on = NULL;
+ struct commit *gave_up_on = NULL;
struct lazy_queue queue = LAZY_QUEUE_INIT;
struct commit_name *n;
struct possible_tag all_matches[MAX_TAGS];
unsigned int match_cnt = 0, annotated_cnt = 0, cur_match;
unsigned long seen_commits = 0;
unsigned int unannotated_cnt = 0;
- cmit = lookup_commit_reference(the_repository, oid);
-
n = find_commit_name(&cmit->object.oid);
if (n && (tags || all || n->prio == 2)) {
/*
* Exact match to an existing ref.
*/
append_name(n, dst);
if (n->misnamed || longformat)
- append_suffix(0, n->tag ? get_tagged_oid(n->tag) : oid, dst);
+ append_suffix(0, n->tag ? get_tagged_oid(n->tag) : &cmit->object.oid, dst);
if (suffix)
strbuf_addstr(dst, suffix);
return;
@@ -528,7 +526,7 @@ static void describe_commit(struct object_id *oid, struct strbuf *dst)
}
struct process_commit_data {
- struct object_id current_commit;
+ struct commit *current_commit;
struct object_id looking_for;
struct strbuf *dst;
struct rev_info *revs;
@@ -537,7 +535,7 @@ struct process_commit_data {
static void process_commit(struct commit *commit, void *data)
{
struct process_commit_data *pcd = data;
- pcd->current_commit = commit->object.oid;
+ pcd->current_commit = commit;
}
static void process_object(struct object *obj, const char *path, void *data)
@@ -546,7 +544,7 @@ static void process_object(struct object *obj, const char *path, void *data)
if (oideq(&pcd->looking_for, &obj->oid) && !pcd->dst->len) {
reset_revision_walk();
- describe_commit(&pcd->current_commit, pcd->dst);
+ describe_commit(pcd->current_commit, pcd->dst);
strbuf_addf(pcd->dst, ":%s", path);
clear_prio_queue(&pcd->revs->commits);
}
@@ -556,7 +554,7 @@ static void describe_blob(struct object_id oid, struct strbuf *dst)
{
struct rev_info revs;
struct strvec args = STRVEC_INIT;
- struct process_commit_data pcd = { *null_oid(the_hash_algo), oid, dst, &revs};
+ struct process_commit_data pcd = { NULL, oid, dst, &revs};
strvec_pushl(&args, "internal: The first arg is not parsed",
"--objects", "--in-commit-order", "--reverse", "HEAD",
@@ -589,7 +587,7 @@ static void describe(const char *arg, int last_one)
cmit = lookup_commit_reference_gently(the_repository, &oid, 1);
if (cmit)
- describe_commit(&oid, &sb);
+ describe_commit(cmit, &sb);
else if (odb_read_object_info(the_repository->objects,
&oid, NULL) == OBJ_BLOB)
describe_blob(oid, &sb);
