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-rw-r--r--refs/files-backend.c110
1 files changed, 95 insertions, 15 deletions
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 4a0343d827..bc3347d18c 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -68,6 +68,12 @@
*/
#define REF_DELETED_RMDIR (1 << 9)
+/*
+ * Used to indicate that the reflog-only update has been created via
+ * `split_head_update()`.
+ */
+#define REF_LOG_VIA_SPLIT (1 << 14)
+
struct ref_lock {
char *ref_name;
struct lock_file lk;
@@ -2164,7 +2170,9 @@ static int files_delete_reflog(struct ref_store *ref_store,
return ret;
}
-static int show_one_reflog_ent(struct files_ref_store *refs, struct strbuf *sb,
+static int show_one_reflog_ent(struct files_ref_store *refs,
+ const char *refname,
+ struct strbuf *sb,
each_reflog_ent_fn fn, void *cb_data)
{
struct object_id ooid, noid;
@@ -2191,7 +2199,7 @@ static int show_one_reflog_ent(struct files_ref_store *refs, struct strbuf *sb,
message += 6;
else
message += 7;
- return fn(&ooid, &noid, p, timestamp, tz, message, cb_data);
+ return fn(refname, &ooid, &noid, p, timestamp, tz, message, cb_data);
}
static char *find_beginning_of_line(char *bob, char *scan)
@@ -2275,7 +2283,7 @@ static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
scanp = bp;
endp = bp + 1;
- ret = show_one_reflog_ent(refs, &sb, fn, cb_data);
+ ret = show_one_reflog_ent(refs, refname, &sb, fn, cb_data);
strbuf_reset(&sb);
if (ret)
break;
@@ -2287,7 +2295,7 @@ static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
* Process it, and we can end the loop.
*/
strbuf_splice(&sb, 0, 0, buf, endp - buf);
- ret = show_one_reflog_ent(refs, &sb, fn, cb_data);
+ ret = show_one_reflog_ent(refs, refname, &sb, fn, cb_data);
strbuf_reset(&sb);
break;
}
@@ -2337,7 +2345,7 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store,
return -1;
while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
- ret = show_one_reflog_ent(refs, &sb, fn, cb_data);
+ ret = show_one_reflog_ent(refs, refname, &sb, fn, cb_data);
fclose(logfp);
strbuf_release(&sb);
return ret;
@@ -2476,9 +2484,10 @@ static enum ref_transaction_error split_head_update(struct ref_update *update,
new_update = ref_transaction_add_update(
transaction, "HEAD",
- update->flags | REF_LOG_ONLY | REF_NO_DEREF,
+ update->flags | REF_LOG_ONLY | REF_NO_DEREF | REF_LOG_VIA_SPLIT,
&update->new_oid, &update->old_oid,
NULL, NULL, update->committer_info, update->msg);
+ new_update->parent_update = update;
/*
* Add "HEAD". This insertion is O(N) in the transaction
@@ -2549,7 +2558,6 @@ static enum ref_transaction_error split_symref_update(struct ref_update *update,
* done when new_update is processed.
*/
update->flags |= REF_LOG_ONLY | REF_NO_DEREF;
- update->flags &= ~REF_HAVE_OLD;
return 0;
}
@@ -2562,12 +2570,37 @@ static enum ref_transaction_error split_symref_update(struct ref_update *update,
*/
static enum ref_transaction_error check_old_oid(struct ref_update *update,
struct object_id *oid,
+ struct strbuf *referent,
struct strbuf *err)
{
- if (!(update->flags & REF_HAVE_OLD) ||
- oideq(oid, &update->old_oid))
+ if (update->flags & REF_LOG_ONLY ||
+ !(update->flags & REF_HAVE_OLD))
return 0;
+ if (oideq(oid, &update->old_oid)) {
+ /*
+ * Normally matching the expected old oid is enough. Either we
+ * found the ref at the expected state, or we are creating and
+ * expect the null oid (and likewise found nothing).
+ *
+ * But there is one exception for the null oid: if we found a
+ * symref pointing to nothing we'll also get the null oid. In
+ * regular recursive mode, that's good (we'll write to what the
+ * symref points to, which doesn't exist). But in no-deref
+ * mode, it means we'll clobber the symref, even though the
+ * caller asked for this to be a creation event. So flag
+ * that case to preserve the dangling symref.
+ */
+ if ((update->flags & REF_NO_DEREF) && referent->len &&
+ is_null_oid(oid)) {
+ strbuf_addf(err, "cannot lock ref '%s': "
+ "dangling symref already exists",
+ ref_update_original_update_refname(update));
+ return REF_TRANSACTION_ERROR_CREATE_EXISTS;
+ }
+ return 0;
+ }
+
if (is_null_oid(&update->old_oid)) {
strbuf_addf(err, "cannot lock ref '%s': "
"reference already exists",
@@ -2655,7 +2688,36 @@ static enum ref_transaction_error lock_ref_for_update(struct files_ref_store *re
update->backend_data = lock;
- if (update->type & REF_ISSYMREF) {
+ if (update->flags & REF_LOG_VIA_SPLIT) {
+ struct ref_lock *parent_lock;
+
+ if (!update->parent_update)
+ BUG("split update without a parent");
+
+ parent_lock = update->parent_update->backend_data;
+
+ /*
+ * Check that "HEAD" didn't racily change since we have looked
+ * it up. If it did we must refuse to write the reflog entry.
+ *
+ * Note that this does not catch all races: if "HEAD" was
+ * racily changed to point to one of the refs part of the
+ * transaction then we would miss writing the split reflog
+ * entry for "HEAD".
+ */
+ if (!(update->type & REF_ISSYMREF) ||
+ strcmp(update->parent_update->refname, referent.buf)) {
+ strbuf_addstr(err, "HEAD has been racily updated");
+ ret = REF_TRANSACTION_ERROR_GENERIC;
+ goto out;
+ }
+
+ if (update->flags & REF_HAVE_OLD) {
+ oidcpy(&lock->old_oid, &update->old_oid);
+ } else {
+ oidcpy(&lock->old_oid, &parent_lock->old_oid);
+ }
+ } else if (update->type & REF_ISSYMREF) {
if (update->flags & REF_NO_DEREF) {
/*
* We won't be reading the referent as part of
@@ -2677,7 +2739,8 @@ static enum ref_transaction_error lock_ref_for_update(struct files_ref_store *re
if (update->old_target)
ret = ref_update_check_old_target(referent.buf, update, err);
else
- ret = check_old_oid(update, &lock->old_oid, err);
+ ret = check_old_oid(update, &lock->old_oid,
+ &referent, err);
if (ret)
goto out;
} else {
@@ -2709,7 +2772,8 @@ static enum ref_transaction_error lock_ref_for_update(struct files_ref_store *re
ret = REF_TRANSACTION_ERROR_EXPECTED_SYMREF;
goto out;
} else {
- ret = check_old_oid(update, &lock->old_oid, err);
+ ret = check_old_oid(update, &lock->old_oid,
+ &referent, err);
if (ret) {
goto out;
}
@@ -3031,6 +3095,20 @@ static int parse_and_write_reflog(struct files_ref_store *refs,
struct ref_lock *lock,
struct strbuf *err)
{
+ struct object_id *old_oid = &lock->old_oid;
+
+ if (update->flags & REF_LOG_USE_PROVIDED_OIDS) {
+ if (!(update->flags & REF_HAVE_OLD) ||
+ !(update->flags & REF_HAVE_NEW) ||
+ !(update->flags & REF_LOG_ONLY)) {
+ strbuf_addf(err, _("trying to write reflog for '%s'"
+ "with incomplete values"), update->refname);
+ return REF_TRANSACTION_ERROR_GENERIC;
+ }
+
+ old_oid = &update->old_oid;
+ }
+
if (update->new_target) {
/*
* We want to get the resolved OID for the target, to ensure
@@ -3048,7 +3126,7 @@ static int parse_and_write_reflog(struct files_ref_store *refs,
}
}
- if (files_log_ref_write(refs, lock->ref_name, &lock->old_oid,
+ if (files_log_ref_write(refs, lock->ref_name, old_oid,
&update->new_oid, update->committer_info,
update->msg, update->flags, err)) {
char *old_msg = strbuf_detach(err, NULL);
@@ -3116,7 +3194,8 @@ static int files_transaction_finish_initial(struct files_ref_store *refs,
for (i = 0; i < transaction->nr; i++) {
struct ref_update *update = transaction->updates[i];
- if ((update->flags & REF_HAVE_OLD) &&
+ if (!(update->flags & REF_LOG_ONLY) &&
+ (update->flags & REF_HAVE_OLD) &&
!is_null_oid(&update->old_oid))
BUG("initial ref transaction with old_sha1 set");
@@ -3363,7 +3442,8 @@ struct expire_reflog_cb {
dry_run:1;
};
-static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid,
+static int expire_reflog_ent(const char *refname UNUSED,
+ struct object_id *ooid, struct object_id *noid,
const char *email, timestamp_t timestamp, int tz,
const char *message, void *cb_data)
{
generated by cgit v1.2.3 (git 2.46.0) at 2025-11-08 18:30:37 +0000