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| author | Karthik Nayak <karthik.188@gmail.com> | 2025-04-08 10:51:10 +0200 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2025-04-08 07:57:20 -0700 |
| commit | 23fc8e4f613179900ce28da959757a387543b468 (patch) | |
| tree | 99a5b2a338fa11532894ec2e5f8d454fe7eba939 /refs.h | |
| parent | 76e760b99923cb9afb52ef08607f736ff3eeaad7 (diff) | |
| download | git-23fc8e4f613179900ce28da959757a387543b468.tar.gz | |
refs: implement batch reference update support
Git supports making reference updates with or without transactions.
Updates with transactions are generally better optimized. But
transactions are all or nothing. This means, if a user wants to batch
updates to take advantage of the optimizations without the hard
requirement that all updates must succeed, there is no way currently to
do so. Particularly with the reftable backend where batching multiple
reference updates is more efficient than performing them sequentially.
Introduce batched update support with a new flag,
'REF_TRANSACTION_ALLOW_FAILURE'. Batched updates while different from
transactions, use the transaction infrastructure under the hood. When
enabled, this flag allows individual reference updates that would
typically cause the entire transaction to fail due to non-system-related
errors to be marked as rejected while permitting other updates to
proceed. System errors referred by 'REF_TRANSACTION_ERROR_GENERIC'
continue to result in the entire transaction failing. This approach
enhances flexibility while preserving transactional integrity where
necessary.
The implementation introduces several key components:
- Add 'rejection_err' field to struct `ref_update` to track failed
updates with failure reason.
- Add a new struct `ref_transaction_rejections` and a field within
`ref_transaction` to this struct to allow quick iteration over
rejected updates.
- Modify reference backends (files, packed, reftable) to handle
partial transactions by using `ref_transaction_set_rejected()`
instead of failing the entire transaction when
`REF_TRANSACTION_ALLOW_FAILURE` is set.
- Add `ref_transaction_for_each_rejected_update()` to let callers
examine which updates were rejected and why.
This foundational change enables batched update support throughout the
reference subsystem. A following commit will expose this capability to
users by adding a `--batch-updates` flag to 'git-update-ref(1)',
providing both a user-facing feature and a testable implementation.
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Acked-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'refs.h')
| -rw-r--r-- | refs.h | 22 |
1 files changed, 22 insertions, 0 deletions
@@ -667,6 +667,13 @@ enum ref_transaction_flag { * either be absent or null_oid. */ REF_TRANSACTION_FLAG_INITIAL = (1 << 0), + + /* + * The transaction mechanism by default fails all updates if any conflict + * is detected. This flag allows transactions to partially apply updates + * while rejecting updates which do not match the expected state. + */ + REF_TRANSACTION_ALLOW_FAILURE = (1 << 1), }; /* @@ -898,6 +905,21 @@ void ref_transaction_for_each_queued_update(struct ref_transaction *transaction, void *cb_data); /* + * Execute the given callback function for each of the reference updates which + * have been rejected in the given transaction. + */ +typedef void ref_transaction_for_each_rejected_update_fn(const char *refname, + const struct object_id *old_oid, + const struct object_id *new_oid, + const char *old_target, + const char *new_target, + enum ref_transaction_error err, + void *cb_data); +void ref_transaction_for_each_rejected_update(struct ref_transaction *transaction, + ref_transaction_for_each_rejected_update_fn cb, + void *cb_data); + +/* * Free `*transaction` and all associated data. */ void ref_transaction_free(struct ref_transaction *transaction); |