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Merge branch 'jk/no-clobber-dangling-symref-with-fetch'

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"git fetch" can clobber a symref that is dangling when the
remote-tracking HEAD is set to auto update, which has been
corrected.

* jk/no-clobber-dangling-symref-with-fetch:
  refs: do not clobber dangling symrefs
  t5510: prefer "git -C" to subshell for followRemoteHEAD tests
  t5510: stop changing top-level working directory
  t5510: make confusing config cleanup more explicit
This commit is contained in:
Junio C Hamano
2025-08-29 09:44:37 -07:00
parent 040f05e824 450fc2bace
commit fea9d18c53
4 changed files with 320 additions and 310 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
refs/files-backend.c
View File

@@ -2515,13 +2515,37 @@ 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_LOG_ONLY ||
!(update->flags & REF_HAVE_OLD) ||
oideq(oid, &update->old_oid))
!(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",
@@ -2661,7 +2685,8 @@ 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 {
@@ -2693,7 +2718,8 @@ 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;
}

30
refs/reftable-backend.c
View File

@@ -1274,9 +1274,33 @@ static enum ref_transaction_error prepare_single_update(struct reftable_ref_stor
ret = ref_update_check_old_target(referent->buf, u, err);
if (ret)
return ret;
} else if ((u->flags & (REF_LOG_ONLY | REF_HAVE_OLD)) == REF_HAVE_OLD &&
!oideq(&current_oid, &u->old_oid)) {
if (is_null_oid(&u->old_oid)) {
} else if ((u->flags & (REF_LOG_ONLY | REF_HAVE_OLD)) == REF_HAVE_OLD) {
if (oideq(&current_oid, &u->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.
*
* Everything else is OK and we can fall through to the
* end of the conditional chain.
*/
if ((u->flags & REF_NO_DEREF) &&
referent->len &&
is_null_oid(&u->old_oid)) {
strbuf_addf(err, _("cannot lock ref '%s': "
"dangling symref already exists"),
ref_update_original_update_refname(u));
return REF_TRANSACTION_ERROR_CREATE_EXISTS;
}
} else if (is_null_oid(&u->old_oid)) {
strbuf_addf(err, _("cannot lock ref '%s': "
"reference already exists"),
ref_update_original_update_refname(u));