Subject: [PATCH 0/4] refs: remove virtual `delete_refs()` function

From: Patrick Steinhardt <[email-masked]>
Date: Tue, 14 Nov 2023 09:58:34 +0100

Hi,

this patch series refactors the virtual `delete_refs()` function to
instead be implemented generically via a single reference transaction.

The main intent of this patch series is to reduce complexity that we
have in the reference backends so that it becomes easier to implement
new backends that have the same semantics as others. But at the same
time, benchmarks show that the new generic code is even faster than the
old backend-specific code. This is mostly because we avoid the overhead
of per-reference transactions when deleting many references, but also
because the transactional code in the files backend knows to avoid
rewriting the packed-refs file in case it contains none of the refs that
are to be deleted.

So in the end we have less duplicate code in the files backend, make it
easier to implement new backends, and have faster deletion of many refs
in the files backend.

Patrick

Patrick Steinhardt (4):
  t5510: ensure that the packed-refs file needs locking
  refs/files: use transactions to delete references
  refs: deduplicate code to delete references
  refs: remove `delete_refs` callback from backends

 refs.c                | 48 ++++++++++++++++++++++++++++++++++++++---
 refs/debug.c          | 15 -------------
 refs/files-backend.c  | 49 ------------------------------------------
 refs/packed-backend.c | 50 -------------------------------------------
 refs/refs-internal.h  |  3 ---
 t/t5510-fetch.sh      |  1 +
 6 files changed, 46 insertions(+), 120 deletions(-)

base-commit: e0939bec273052b1a8d69db4a3f7c87aaf83e220
-- 
2.42.0