From: Jiang Xin <zhiyou.jx@xxxxxxxxxxxxxxx>
When using "git branch -d" or "git tag -d" to delete one or multiple
references, command "reference-transaction committed" will be called
repeatedly for the same references. This is because the function
"refs_delete_refs()" is called twice, once for loose ref-store and once
for packed ref-store.
The old story starts when running the function "refs_delete_refs()" on a
loose ref-store:
1. Try to remove the references from packed ref-store.
1.1. Lock the packed-ref-store by calling "packed_refs_lock()" in
"files_delete_refs()".
1.2. Call "refs_delete_refs()" on packed-ref-store, and then call
"packed_delete_refs()".
1.3. Create a transaction for packed-ref-store in function
"packed_delete_refs()" by calling the function
"ref_store_transaction_begin()".
2.2. Add update entries for all the references to be removed into
this transaction by calling "ref_transaction_delete()".
2.3. Call "ref_transaction_commit()" to commit the transaction.
2.4. Unlock the packed-ref-store.
2. Try to remove the references one by one by calling the function
"refs_delete_ref()".
2.1. Create a new transaction on loose-ref-store by calling
"ref_store_transaction_begin()".
2.2. Call "ref_transaction_delete()" to add a update entry
for the reference to be deleted into the transaction.
2.3. In "ref_transaction_commit()", it will call functions
"files_transaction_prepare()" and "files_transaction_finish()"
to commit the transaction.
2.3.1. Lock the loose reference.
2.3.2. Create a new packed-transaction, and add a new update
entry to this packed-transaction. The previous step 1
makes this operation unnecessary.
2.3.3. Lock the packed-ref-store and call fucntion
"is_packed_transaction_needed()" to check whether it
is necessary to commit the transaction, and then
abort the transaction because the reference is already
removed from the packed-ref-store in step 1.
2.3.4. Remove the reflog and the loose reference file for
the reference to be deleted.
2.3.4. Unlock the loose reference.
>From the above steps, we can see that "refs_delete_refs()" is not an
atomic operation, but a semi-atomic operation. The operation is atomic
if all references to be deleted are in the packed ref-store, but not
if some references are loose references because we delete the loose
references one by one by calling "refs_delete_ref()" .
Refactored function "files_delete_refs()" to delete references within a
transaction, so the "reference-transaction" hook will only run once for
deleted branches and tags.
The behavior of the following git commands and the last two testcases
have been fixed in t1416:
* git branch -d <branch>
* git tag -d <tag>
A testcase in t5510 is broken because we used to call the function
"packed_refs_lock()", but it is not necessary if the deleted reference
is not in the "packed-refs" file.
Signed-off-by: Jiang Xin <zhiyou.jx@xxxxxxxxxxxxxxx>
---
refs/files-backend.c | 21 +++++-----
refs/packed-backend.c | 51 +-----------------------
t/t1416-ref-transaction-hooks.sh | 68 +-------------------------------
t/t5510-fetch.sh | 16 ++++++++
4 files changed, 28 insertions(+), 128 deletions(-)
diff --git a/refs/files-backend.c b/refs/files-backend.c
index e029f5a885..8f3deddc71 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1268,31 +1268,27 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
static int files_delete_refs(struct ref_store *ref_store, const char *msg,
struct string_list *refnames, unsigned int flags)
{
- struct files_ref_store *refs =
- files_downcast(ref_store, REF_STORE_WRITE, "delete_refs");
+ struct ref_transaction *transaction;
struct strbuf err = STRBUF_INIT;
int i, result = 0;
if (!refnames->nr)
return 0;
- if (packed_refs_lock(refs->packed_ref_store, 0, &err))
- goto error;
-
- if (refs_delete_refs(refs->packed_ref_store, msg, refnames, flags)) {
- packed_refs_unlock(refs->packed_ref_store);
+ transaction = ref_store_transaction_begin(ref_store, &err);
+ if (!transaction)
goto error;
- }
-
- packed_refs_unlock(refs->packed_ref_store);
for (i = 0; i < refnames->nr; i++) {
const char *refname = refnames->items[i].string;
-
- if (refs_delete_ref(&refs->base, msg, refname, NULL, flags))
+ if (ref_transaction_delete(transaction, refname, NULL,
+ flags, msg, &err))
result |= error(_("could not remove reference %s"), refname);
}
+ if (ref_transaction_commit(transaction, &err))
+ goto error;
+ ref_transaction_free(transaction);
strbuf_release(&err);
return result;
@@ -1309,6 +1305,7 @@ static int files_delete_refs(struct ref_store *ref_store, const char *msg,
else
error(_("could not delete references: %s"), err.buf);
+ ref_transaction_free(transaction);
strbuf_release(&err);
return -1;
}
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 97b6837767..fdb7a0a52c 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -1519,55 +1519,6 @@ static int packed_initial_transaction_commit(struct ref_store *ref_store,
return ref_transaction_commit(transaction, err);
}
-static int packed_delete_refs(struct ref_store *ref_store, const char *msg,
- struct string_list *refnames, unsigned int flags)
-{
- struct packed_ref_store *refs =
- packed_downcast(ref_store, REF_STORE_WRITE, "delete_refs");
- struct strbuf err = STRBUF_INIT;
- struct ref_transaction *transaction;
- struct string_list_item *item;
- int ret;
-
- (void)refs; /* We need the check above, but don't use the variable */
-
- if (!refnames->nr)
- return 0;
-
- /*
- * Since we don't check the references' old_oids, the
- * individual updates can't fail, so we can pack all of the
- * updates into a single transaction.
- */
-
- transaction = ref_store_transaction_begin(ref_store, &err);
- if (!transaction)
- return -1;
-
- for_each_string_list_item(item, refnames) {
- if (ref_transaction_delete(transaction, item->string, NULL,
- flags, msg, &err)) {
- warning(_("could not delete reference %s: %s"),
- item->string, err.buf);
- strbuf_reset(&err);
- }
- }
-
- ret = ref_transaction_commit(transaction, &err);
-
- if (ret) {
- if (refnames->nr == 1)
- error(_("could not delete reference %s: %s"),
- refnames->items[0].string, err.buf);
- else
- error(_("could not delete references: %s"), err.buf);
- }
-
- ref_transaction_free(transaction);
- strbuf_release(&err);
- return ret;
-}
-
static int packed_pack_refs(struct ref_store *ref_store, unsigned int flags)
{
/*
@@ -1595,7 +1546,7 @@ struct ref_storage_be refs_be_packed = {
.pack_refs = packed_pack_refs,
.create_symref = NULL,
- .delete_refs = packed_delete_refs,
+ .delete_refs = NULL,
.rename_ref = NULL,
.copy_ref = NULL,
diff --git a/t/t1416-ref-transaction-hooks.sh b/t/t1416-ref-transaction-hooks.sh
index 77996017d7..3d39e1634a 100755
--- a/t/t1416-ref-transaction-hooks.sh
+++ b/t/t1416-ref-transaction-hooks.sh
@@ -789,39 +789,7 @@ test_expect_success "branch: rename branches" '
test_cmp_heads_and_tags -C workdir expect
'
-# Mismatched hook output for "git branch -d":
-#
-# * The delete branches operation should be treated as one transaction,
-# but was splitted into several transactions on loose references,
-# and the "reference-transaction committed" command was executed
-# redundantly on the packed-ref-store.
-#
-# The differences are as follows:
-#
-# @@ -2,11 +2,19 @@
-# <ZERO-OID> <ZERO-OID> refs/heads/topic1
-# <ZERO-OID> <ZERO-OID> refs/heads/topic2
-# <ZERO-OID> <ZERO-OID> refs/heads/topic3
-# +## Call hook: reference-transaction committed ##
-# +<ZERO-OID> <ZERO-OID> refs/heads/topic1
-# +<ZERO-OID> <ZERO-OID> refs/heads/topic2
-# +<ZERO-OID> <ZERO-OID> refs/heads/topic3
-# +## Call hook: reference-transaction prepared ##
-# +<ZERO-OID> <ZERO-OID> refs/heads/topic1
-# +## Call hook: reference-transaction committed ##
-# +<ZERO-OID> <ZERO-OID> refs/heads/topic1
-# ## Call hook: reference-transaction prepared ##
-# -<COMMIT-A> <ZERO-OID> refs/heads/topic1
-# <COMMIT-B> <ZERO-OID> refs/heads/topic2
-# -<COMMIT-C> <ZERO-OID> refs/heads/topic3
-# ## Call hook: reference-transaction committed ##
-# -<COMMIT-A> <ZERO-OID> refs/heads/topic1
-# <COMMIT-B> <ZERO-OID> refs/heads/topic2
-# +## Call hook: reference-transaction prepared ##
-# +<COMMIT-C> <ZERO-OID> refs/heads/topic3
-# +## Call hook: reference-transaction committed ##
-# <COMMIT-C> <ZERO-OID> refs/heads/topic3
-test_expect_failure "branch: remove branches" '
+test_expect_success "branch: remove branches" '
test_when_finished "rm -f $HOOK_OUTPUT" &&
cat >expect <<-\EOF &&
@@ -950,39 +918,7 @@ test_expect_success "tag: update refs to create loose refs" '
test_cmp_heads_and_tags -C workdir expect
'
-# Mismatched hook output for "git tag -d":
-#
-# * The delete tags operation should be treated as one transaction,
-# but was splitted into several transactions on loose references,
-# and the "reference-transaction committed" command was executed
-# redundantly on the packed-ref-store.
-#
-# The differences are as follows:
-#
-# @@ -2,11 +2,19 @@
-# <ZERO-OID> <ZERO-OID> refs/tags/v1
-# <ZERO-OID> <ZERO-OID> refs/tags/v2
-# <ZERO-OID> <ZERO-OID> refs/tags/v3
-# +## Call hook: reference-transaction committed ##
-# +<ZERO-OID> <ZERO-OID> refs/tags/v1
-# +<ZERO-OID> <ZERO-OID> refs/tags/v2
-# +<ZERO-OID> <ZERO-OID> refs/tags/v3
-# +## Call hook: reference-transaction prepared ##
-# +<ZERO-OID> <ZERO-OID> refs/tags/v1
-# +## Call hook: reference-transaction committed ##
-# +<ZERO-OID> <ZERO-OID> refs/tags/v1
-# ## Call hook: reference-transaction prepared ##
-# -<COMMIT-A> <ZERO-OID> refs/tags/v1
-# <COMMIT-B> <ZERO-OID> refs/tags/v2
-# -<COMMIT-C> <ZERO-OID> refs/tags/v3
-# ## Call hook: reference-transaction committed ##
-# -<COMMIT-A> <ZERO-OID> refs/tags/v1
-# <COMMIT-B> <ZERO-OID> refs/tags/v2
-# +## Call hook: reference-transaction prepared ##
-# +<COMMIT-C> <ZERO-OID> refs/tags/v3
-# +## Call hook: reference-transaction committed ##
-# <COMMIT-C> <ZERO-OID> refs/tags/v3
-test_expect_failure "tag: remove tags with mixed ref_stores" '
+test_expect_success "tag: remove tags with mixed ref_stores" '
test_when_finished "rm -f $HOOK_OUTPUT" &&
cat >expect <<-\EOF &&
diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index b45879a760..dfdab09600 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -168,6 +168,8 @@ test_expect_success REFFILES 'fetch --prune fails to delete branches' '
cd "$D" &&
git clone . prune-fail &&
cd prune-fail &&
+ git update-ref refs/remotes/origin/extrabranch main~ &&
+ git pack-refs --all &&
git update-ref refs/remotes/origin/extrabranch main &&
: this will prevent --prune from locking packed-refs for deleting refs, but adding loose refs still succeeds &&
>.git/packed-refs.new &&
@@ -175,6 +177,20 @@ test_expect_success REFFILES 'fetch --prune fails to delete branches' '
test_must_fail git fetch --prune origin
'
+test_expect_success REFFILES 'fetch --prune ok for loose refs not in locked packed-refs' '
+ cd "$D" &&
+ git clone . prune-ok-ref-not-packed &&
+ (
+ cd prune-ok-ref-not-packed &&
+ git update-ref refs/remotes/origin/extrabranch main &&
+ : for loose refs not in packed-refs, we can delete them even the packed-refs is locked &&
+ :>.git/packed-refs.new &&
+
+ git fetch --prune origin &&
+ test_must_fail git rev-parse refs/remotes/origin/extrabranch --
+ )
+'
+
test_expect_success 'fetch --atomic works with a single branch' '
test_when_finished "rm -rf \"$D\"/atomic" &&
--
2.36.1.25.gc87d5ad63a.dirty
