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Merge branch 'jk/describe-blob' 

"git describe <blob>" misbehaves and/or crashes in some corner
cases, which has been taught to exit with failure gracefully.

* jk/describe-blob:
  describe: pass commit to describe_commit()
  describe: handle blob traversal with no commits
  describe: catch unborn branch in describe_blob()
  describe: error if blob not found
  describe: pass oid struct by const pointer
main
Junio C Hamano 2025-08-29 09:44:37 -07:00
parent fea9d18c53 7c10e48e81
commit c64ec662d0
2 changed files with 55 additions and 16 deletions
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41
builtin/describe.c
View File

@ -352,9 +352,9 @@ 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];
@ -362,8 +362,6 @@ static void describe_commit(struct object_id *oid, struct strbuf *dst)
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)) {
/*
@ -371,7 +369,7 @@ static void describe_commit(struct object_id *oid, struct strbuf *dst)
*/
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;
@ -528,8 +526,8 @@ static void describe_commit(struct object_id *oid, struct strbuf *dst)
}

struct process_commit_data {
struct object_id current_commit;
struct object_id looking_for;
struct commit *current_commit;
const struct object_id *looking_for;
struct strbuf *dst;
struct rev_info *revs;
};
@ -537,30 +535,38 @@ 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)
{
struct process_commit_data *pcd = data;

if (oideq(&pcd->looking_for, &obj->oid) && !pcd->dst->len) {
if (oideq(pcd->looking_for, &obj->oid) && !pcd->dst->len) {
reset_revision_walk();
describe_commit(&pcd->current_commit, pcd->dst);
strbuf_addf(pcd->dst, ":%s", path);
if (pcd->current_commit) {
describe_commit(pcd->current_commit, pcd->dst);
strbuf_addf(pcd->dst, ":%s", path);
}
free_commit_list(pcd->revs->commits);
pcd->revs->commits = NULL;
}
}

static void describe_blob(struct object_id oid, struct strbuf *dst)
static void describe_blob(const 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 object_id head_oid;
struct process_commit_data pcd = { NULL, oid, dst, &revs};

if (repo_get_oid(the_repository, "HEAD", &head_oid))
die(_("cannot search for blob '%s' on an unborn branch"),
oid_to_hex(oid));

strvec_pushl(&args, "internal: The first arg is not parsed",
"--objects", "--in-commit-order", "--reverse", "HEAD",
"--objects", "--in-commit-order", "--reverse",
oid_to_hex(&head_oid),
NULL);

repo_init_revisions(the_repository, &revs, NULL);
@ -574,6 +580,9 @@ static void describe_blob(struct object_id oid, struct strbuf *dst)
reset_revision_walk();
release_revisions(&revs);
strvec_clear(&args);

if (!dst->len)
die(_("blob '%s' not reachable from HEAD"), oid_to_hex(oid));
}

static void describe(const char *arg, int last_one)
@ -590,10 +599,10 @@ 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);
describe_blob(&oid, &sb);
else
die(_("%s is neither a commit nor blob"), arg);


30
t/t6120-describe.sh
View File

@ -409,6 +409,36 @@ test_expect_success 'describe tag object' '
test_grep "fatal: test-blob-1 is neither a commit nor blob" actual
'

test_expect_success 'describe an unreachable blob' '
blob=$(echo not-found-anywhere | git hash-object -w --stdin) &&
test_must_fail git describe $blob 2>actual &&
test_grep "blob .$blob. not reachable from HEAD" actual
'

test_expect_success 'describe blob on an unborn branch' '
oldbranch=$(git symbolic-ref HEAD) &&
test_when_finished "git symbolic-ref HEAD $oldbranch" &&
git symbolic-ref HEAD refs/heads/does-not-exist &&
test_must_fail git describe test-blob 2>actual &&
test_grep "cannot search .* on an unborn branch" actual
'

# This test creates a repository state that we generally try to disallow: HEAD
# is pointing to an object that is not a commit. The ref update code forbids
# non-commit writes directly to HEAD or to any branch in refs/heads/. But we
# can use the loophole of pointing HEAD to another non-branch ref (something we
# should forbid, but don't for historical reasons).
#
# Do not take this test as an endorsement of the loophole! If we ever tighten
# it, it is reasonable to just drop this test entirely.
test_expect_success 'describe blob on a non-commit HEAD' '
oldbranch=$(git symbolic-ref HEAD) &&
test_when_finished "git symbolic-ref HEAD $oldbranch" &&
git symbolic-ref HEAD refs/tags/test-blob &&
test_must_fail git describe test-blob 2>actual &&
test_grep "blob .* not reachable from HEAD" actual
'

test_expect_success ULIMIT_STACK_SIZE 'name-rev works in a deep repo' '
i=1 &&
while test $i -lt 8000