mirrors/git
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

refs: add support for transactional symref updates

Browse Source 
The reference backends currently support transactional reference
updates. While this is exposed to users via 'git-update-ref' and its
'--stdin' mode, it is also used internally within various commands.

However, we do not support transactional updates of symrefs. This commit
adds support for symrefs in both the 'files' and the 'reftable' backend.

Here, we add and use `ref_update_has_null_new_value()`, a helper
function which is used to check if there is a new_value in a reference
update. The new value could either be a symref target `new_target` or a
OID `new_oid`.

We also add another common function `ref_update_check_old_target` which
will be used to check if the update's old_target corresponds to a
reference's current target.

Now transactional updates (verify, create, delete, update) can be used
for:
- regular refs
- symbolic refs
- conversion of regular to symbolic refs and vice versa

This also allows us to expose this to users via new commands in
'git-update-ref' in the future.

Note that a dangling symref update does not record a new reflog entry,
which is unchanged before and after this commit.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Karthik Nayak
2024-05-07 14:58:56 +02:00
committed by Junio C Hamano
parent e9965ba477
commit 644daf7785
4 changed files with 196 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

69
refs/reftable-backend.c
View File

@ -843,7 +843,7 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store,
* There is no need to write the reference deletion
* when the reference in question doesn't exist.
*/
if (u->flags & REF_HAVE_NEW && !is_null_oid(&u->new_oid)) {
if ((u->flags & REF_HAVE_NEW) && !ref_update_has_null_new_value(u)) {
ret = queue_transaction_update(refs, tx_data, u,
&current_oid, err);
if (ret)
@ -894,8 +894,10 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store,
* intertwined with the locking in files-backend.c.
*/
new_update = ref_transaction_add_update(
transaction, referent.buf, new_flags,
&u->new_oid, &u->old_oid, NULL, NULL, u->msg);
transaction, referent.buf, new_flags,
&u->new_oid, &u->old_oid, u->new_target,
u->old_target, u->msg);
new_update->parent_update = u;
/*
@ -925,7 +927,12 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store,
* individual refs. But the error messages match what the files
* backend returns, which keeps our tests happy.
*/
if (u->flags & REF_HAVE_OLD && !oideq(&current_oid, &u->old_oid)) {
if (u->old_target) {
if (ref_update_check_old_target(referent.buf, u, err)) {
ret = -1;
goto done;
}
} else if ((u->flags & REF_HAVE_OLD) && !oideq(&current_oid, &u->old_oid)) {
if (is_null_oid(&u->old_oid))
strbuf_addf(err, _("cannot lock ref '%s': "
"reference already exists"),
@ -1030,7 +1037,9 @@ static int write_transaction_table(struct reftable_writer *writer, void *cb_data
* - `core.logAllRefUpdates` tells us to create the reflog for
* the given ref.
*/
if (u->flags & REF_HAVE_NEW && !(u->type & REF_ISSYMREF) && is_null_oid(&u->new_oid)) {
if ((u->flags & REF_HAVE_NEW) &&
!(u->type & REF_ISSYMREF) &&
ref_update_has_null_new_value(u)) {
struct reftable_log_record log = {0};
struct reftable_iterator it = {0};
@ -1071,24 +1080,52 @@ static int write_transaction_table(struct reftable_writer *writer, void *cb_data
(u->flags & REF_FORCE_CREATE_REFLOG ||
should_write_log(&arg->refs->base, u->refname))) {
struct reftable_log_record *log;
int create_reflog = 1;
ALLOC_GROW(logs, logs_nr + 1, logs_alloc);
log = &logs[logs_nr++];
memset(log, 0, sizeof(*log));
if (u->new_target) {
if (!refs_resolve_ref_unsafe(&arg->refs->base, u->new_target,
RESOLVE_REF_READING, &u->new_oid, NULL)) {
/*
* TODO: currently we skip creating reflogs for dangling
* symref updates. It would be nice to capture this as
* zero oid updates however.
*/
create_reflog = 0;
}
}
fill_reftable_log_record(log);
log->update_index = ts;
log->refname = xstrdup(u->refname);
memcpy(log->value.update.new_hash, u->new_oid.hash, GIT_MAX_RAWSZ);
memcpy(log->value.update.old_hash, tx_update->current_oid.hash, GIT_MAX_RAWSZ);
log->value.update.message =
xstrndup(u->msg, arg->refs->write_options.block_size / 2);
if (create_reflog) {
ALLOC_GROW(logs, logs_nr + 1, logs_alloc);
log = &logs[logs_nr++];
memset(log, 0, sizeof(*log));
fill_reftable_log_record(log);
log->update_index = ts;
log->refname = xstrdup(u->refname);
memcpy(log->value.update.new_hash,
u->new_oid.hash, GIT_MAX_RAWSZ);
memcpy(log->value.update.old_hash,
tx_update->current_oid.hash, GIT_MAX_RAWSZ);
log->value.update.message =
xstrndup(u->msg, arg->refs->write_options.block_size / 2);
}
}
if (u->flags & REF_LOG_ONLY)
continue;
if (u->flags & REF_HAVE_NEW && is_null_oid(&u->new_oid)) {
if (u->new_target) {
struct reftable_ref_record ref = {
.refname = (char *)u->refname,
.value_type = REFTABLE_REF_SYMREF,
.value.symref = (char *)u->new_target,
.update_index = ts,
};
ret = reftable_writer_add_ref(writer, &ref);
if (ret < 0)
goto done;
} else if ((u->flags & REF_HAVE_NEW) && ref_update_has_null_new_value(u)) {
struct reftable_ref_record ref = {
.refname = (char *)u->refname,
.update_index = ts,