From: Xing Xin <xingxin.xx@xxxxxxxxxxxxx>
When using the bundle-uri mechanism with a bundle list containing
multiple interrelated bundles, we encountered a bug where tips from
downloaded bundles were not discovered, thus resulting in rather slow
clones. This was particularly problematic when employing the heuristic
`creationTokens`.
And this is easy to reproduce. Suppose we have a repository with a
single branch `main` pointing to commit `A`, firstly we create a base
bundle with
git bundle create base.bundle main
Then let's add a new commit `B` on top of `A`, so that an incremental
bundle for `main` can be created with
git bundle create incr.bundle A..main
Now we can generate a bundle list with the following content:
[bundle]
version = 1
mode = all
heuristic = creationToken
[bundle "base"]
uri = base.bundle
creationToken = 1
[bundle "incr"]
uri = incr.bundle
creationToken = 2
A fresh clone with the bundle list above would give the expected
`refs/bundles/main` pointing at `B` in new repository, in other words we
already had everything locally from the bundles, but git would still
download everything from server as if we got nothing.
So why the `refs/bundles/main` is not discovered? After some digging I
found that:
1. Bundles in bundle list are downloaded to local files via
`download_bundle_list` or via `fetch_bundles_by_token` for the
creationToken heuristic case.
2. Then it tries to unbundle each bundle via `unbundle_from_file`, which
is called by `unbundle_all_bundles` or called within
`fetch_bundles_by_token` for the creationToken heuristic case.
3. Here, we first read the bundle header to get all the prerequisites
for the bundle, this is done in `read_bundle_header`.
4. Then we call `unbundle`, which calls `verify_bundle` to ensure that
the repository does indeed contain the prerequisites mentioned in the
bundle.
5. The `verify_bundle` will call `parse_object`, within which the
`prepare_packed_git` or `reprepare_packed_git` is eventually called,
which means that the `raw_object_store->packed_git` data gets filled
in and ``packed_git_initialized` is set. This also means consecutive
calls to `prepare_packed_git` doesn't re-initiate
`raw_object_store->packed_git` since `packed_git_initialized` already
is set.
6. If `unbundle` succeeds, it writes some refs via `refs_update_ref`
with `REF_SKIP_OID_VERIFICATION` set. So the bundle refs which can
target arbitrary objects are written to the repository.
7. Finally in `do_fetch_pack_v2`, `mark_complete_and_common_ref` and
`mark_tips` are called with `OBJECT_INFO_QUICK` set to find local
tips. Here it won't call `reprepare_packed_git` anymore so it would
fail to parse oids that only reside in the last bundle.
Back to the example above, when unbunding `incr.bundle`, `base.pack` is
enlisted to `packed_git` bacause of the prerequisites to verify. While
we can not find `B` for negotiation at a latter time because `B` exists
in `incr.pack` which is not enlisted in `packed_git`.
This commit fixes this bug by dropping the `REF_SKIP_OID_VERIFICATION`
flag when writing bundle refs, so we can:
1. Ensure that the bundle refs we are writing are pointing to valid
objects.
2. Ensure all the tips from bundle refs can be correctly parsed.
And a set of negotiation related tests for bundle-uri are added.
Signed-off-by: Xing Xin <xingxin.xx@xxxxxxxxxxxxx>
---
bundle-uri: refresh packed_git if unbundle succeed
cc: Patrick Steinhardt ps@xxxxxx cc: Karthik Nayak karthik.188@xxxxxxxxx
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1730%2Fblanet%2Fxx%2Fbundle-uri-bug-using-bundle-list-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1730/blanet/xx/bundle-uri-bug-using-bundle-list-v2
Pull-Request: https://github.com/gitgitgadget/git/pull/1730
Range-diff vs v1:
1: d4841eea556 ! 1: 8bdeacf1360 bundle-uri: refresh packed_git if unbundle succeed
@@ Metadata
Author: Xing Xin <xingxin.xx@xxxxxxxxxxxxx>
## Commit message ##
- bundle-uri: refresh packed_git if unbundle succeed
+ bundle-uri: verify oid before writing refs
When using the bundle-uri mechanism with a bundle list containing
multiple interrelated bundles, we encountered a bug where tips from
- downloaded bundles were not being discovered, resulting in rather slow
+ downloaded bundles were not discovered, thus resulting in rather slow
clones. This was particularly problematic when employing the heuristic
`creationTokens`.
@@ Commit message
So why the `refs/bundles/main` is not discovered? After some digging I
found that:
- 1. when unbundling a downloaded bundle, a `verify_bundle` is called to
- check its prerequisites if any. The verify procedure would find oids
- so `packed_git` is initialized.
-
- 2. after unbundled all bundles, we would enter `do_fetch_pack_v2`,
- during which `mark_complete_and_common_ref` and `mark_tips` would
- find oids with `OBJECT_INFO_QUICK` flag set, so no new packs would be
- enlisted if `packed_git` has already initialized in 1.
+ 1. Bundles in bundle list are downloaded to local files via
+ `download_bundle_list` or via `fetch_bundles_by_token` for the
+ creationToken heuristic case.
+ 2. Then it tries to unbundle each bundle via `unbundle_from_file`, which
+ is called by `unbundle_all_bundles` or called within
+ `fetch_bundles_by_token` for the creationToken heuristic case.
+ 3. Here, we first read the bundle header to get all the prerequisites
+ for the bundle, this is done in `read_bundle_header`.
+ 4. Then we call `unbundle`, which calls `verify_bundle` to ensure that
+ the repository does indeed contain the prerequisites mentioned in the
+ bundle.
+ 5. The `verify_bundle` will call `parse_object`, within which the
+ `prepare_packed_git` or `reprepare_packed_git` is eventually called,
+ which means that the `raw_object_store->packed_git` data gets filled
+ in and ``packed_git_initialized` is set. This also means consecutive
+ calls to `prepare_packed_git` doesn't re-initiate
+ `raw_object_store->packed_git` since `packed_git_initialized` already
+ is set.
+ 6. If `unbundle` succeeds, it writes some refs via `refs_update_ref`
+ with `REF_SKIP_OID_VERIFICATION` set. So the bundle refs which can
+ target arbitrary objects are written to the repository.
+ 7. Finally in `do_fetch_pack_v2`, `mark_complete_and_common_ref` and
+ `mark_tips` are called with `OBJECT_INFO_QUICK` set to find local
+ tips. Here it won't call `reprepare_packed_git` anymore so it would
+ fail to parse oids that only reside in the last bundle.
Back to the example above, when unbunding `incr.bundle`, `base.pack` is
- enlisted to `packed_git` bacause of the prerequisites to verify. Then we
- can not find `B` for negotiation at a latter time bacause `B` exists in
- `incr.pack` which is not enlisted in `packed_git`.
+ enlisted to `packed_git` bacause of the prerequisites to verify. While
+ we can not find `B` for negotiation at a latter time because `B` exists
+ in `incr.pack` which is not enlisted in `packed_git`.
+
+ This commit fixes this bug by dropping the `REF_SKIP_OID_VERIFICATION`
+ flag when writing bundle refs, so we can:
- This commit fixes this by adding a `reprepare_packed_git` call for every
- successfully unbundled bundle, which ensures to enlist all generated
- packs from bundle uri. And a set of negotiation related tests are added.
+ 1. Ensure that the bundle refs we are writing are pointing to valid
+ objects.
+ 2. Ensure all the tips from bundle refs can be correctly parsed.
+
+ And a set of negotiation related tests for bundle-uri are added.
Signed-off-by: Xing Xin <xingxin.xx@xxxxxxxxxxxxx>
## bundle-uri.c ##
-@@
- #include "refs.h"
- #include "run-command.h"
- #include "hashmap.h"
-+#include "packfile.h"
- #include "pkt-line.h"
- #include "config.h"
- #include "remote.h"
@@ bundle-uri.c: static int unbundle_from_file(struct repository *r, const char *file)
- VERIFY_BUNDLE_QUIET)))
- return 1;
+ refs_update_ref(get_main_ref_store(the_repository),
+ "fetched bundle", bundle_ref.buf, oid,
+ has_old ? &old_oid : NULL,
+- REF_SKIP_OID_VERIFICATION,
+- UPDATE_REFS_MSG_ON_ERR);
++ 0, UPDATE_REFS_MSG_ON_ERR);
+ }
-+ reprepare_packed_git(r);
-+
- /*
- * Convert all refs/heads/ from the bundle into refs/bundles/
- * in the local repository.
+ bundle_header_release(&header);
## t/t5558-clone-bundle-uri.sh ##
@@ t/t5558-clone-bundle-uri.sh: test_expect_success 'fail to clone from non-bundle file' '
bundle-uri.c | 3 +-
t/t5558-clone-bundle-uri.sh | 129 ++++++++++++++++++++++++++++++++++++
2 files changed, 130 insertions(+), 2 deletions(-)
diff --git a/bundle-uri.c b/bundle-uri.c
index 91b3319a5c1..65666a11d9c 100644
--- a/bundle-uri.c
+++ b/bundle-uri.c
@@ -400,8 +400,7 @@ static int unbundle_from_file(struct repository *r, const char *file)
refs_update_ref(get_main_ref_store(the_repository),
"fetched bundle", bundle_ref.buf, oid,
has_old ? &old_oid : NULL,
- REF_SKIP_OID_VERIFICATION,
- UPDATE_REFS_MSG_ON_ERR);
+ 0, UPDATE_REFS_MSG_ON_ERR);
}
bundle_header_release(&header);
diff --git a/t/t5558-clone-bundle-uri.sh b/t/t5558-clone-bundle-uri.sh
index 1ca5f745e73..a5b04d6f187 100755
--- a/t/t5558-clone-bundle-uri.sh
+++ b/t/t5558-clone-bundle-uri.sh
@@ -20,7 +20,10 @@ test_expect_success 'fail to clone from non-bundle file' '
test_expect_success 'create bundle' '
git init clone-from &&
git -C clone-from checkout -b topic &&
+
test_commit -C clone-from A &&
+ git -C clone-from bundle create A.bundle topic &&
+
test_commit -C clone-from B &&
git -C clone-from bundle create B.bundle topic
'
@@ -259,6 +262,132 @@ test_expect_success 'clone bundle list (file, any mode, all failures)' '
! grep "refs/bundles/" refs
'
+#########################################################################
+# Clone negotiation related tests begin here
+
+test_expect_success 'negotiation: bundle with part of wanted commits' '
+ test_when_finished rm -rf trace*.txt &&
+ GIT_TRACE_PACKET="$(pwd)/trace-packet.txt" \
+ git clone --no-local --bundle-uri="clone-from/A.bundle" \
+ clone-from nego-bundle-part &&
+ git -C nego-bundle-part for-each-ref --format="%(refname)" >refs &&
+ grep "refs/bundles/" refs >actual &&
+ cat >expect <<-\EOF &&
+ refs/bundles/topic
+ EOF
+ test_cmp expect actual &&
+ # Ensure that refs/bundles/topic are sent as "have".
+ grep "clone> have $(git -C clone-from rev-parse A)" trace-packet.txt
+'
+
+test_expect_success 'negotiation: bundle with all wanted commits' '
+ test_when_finished rm -rf trace*.txt &&
+ GIT_TRACE_PACKET="$(pwd)/trace-packet.txt" \
+ git clone --no-local --single-branch --branch=topic --no-tags \
+ --bundle-uri="clone-from/B.bundle" \
+ clone-from nego-bundle-all &&
+ git -C nego-bundle-all for-each-ref --format="%(refname)" >refs &&
+ grep "refs/bundles/" refs >actual &&
+ cat >expect <<-\EOF &&
+ refs/bundles/topic
+ EOF
+ test_cmp expect actual &&
+ # We already have all needed commits so no "want" needed.
+ ! grep "clone> want " trace-packet.txt
+'
+
+test_expect_success 'negotiation: bundle list (no heuristic)' '
+ test_when_finished rm -f trace*.txt &&
+ cat >bundle-list <<-EOF &&
+ [bundle]
+ version = 1
+ mode = all
+
+ [bundle "bundle-1"]
+ uri = file://$(pwd)/clone-from/bundle-1.bundle
+
+ [bundle "bundle-2"]
+ uri = file://$(pwd)/clone-from/bundle-2.bundle
+ EOF
+
+ GIT_TRACE_PACKET="$(pwd)/trace-packet.txt" \
+ git clone --no-local --bundle-uri="file://$(pwd)/bundle-list" \
+ clone-from nego-bundle-list-no-heuristic &&
+
+ git -C nego-bundle-list-no-heuristic for-each-ref --format="%(refname)" >refs &&
+ grep "refs/bundles/" refs >actual &&
+ cat >expect <<-\EOF &&
+ refs/bundles/base
+ refs/bundles/left
+ EOF
+ test_cmp expect actual &&
+ grep "clone> have $(git -C nego-bundle-list-no-heuristic rev-parse refs/bundles/left)" trace-packet.txt
+'
+
+test_expect_success 'negotiation: bundle list (creationToken)' '
+ test_when_finished rm -f trace*.txt &&
+ cat >bundle-list <<-EOF &&
+ [bundle]
+ version = 1
+ mode = all
+ heuristic = creationToken
+
+ [bundle "bundle-1"]
+ uri = file://$(pwd)/clone-from/bundle-1.bundle
+ creationToken = 1
+
+ [bundle "bundle-2"]
+ uri = file://$(pwd)/clone-from/bundle-2.bundle
+ creationToken = 2
+ EOF
+
+ GIT_TRACE_PACKET="$(pwd)/trace-packet.txt" \
+ git clone --no-local --bundle-uri="file://$(pwd)/bundle-list" \
+ clone-from nego-bundle-list-heuristic &&
+
+ git -C nego-bundle-list-heuristic for-each-ref --format="%(refname)" >refs &&
+ grep "refs/bundles/" refs >actual &&
+ cat >expect <<-\EOF &&
+ refs/bundles/base
+ refs/bundles/left
+ EOF
+ test_cmp expect actual &&
+ grep "clone> have $(git -C nego-bundle-list-heuristic rev-parse refs/bundles/left)" trace-packet.txt
+'
+
+test_expect_success 'negotiation: bundle list with all wanted commits' '
+ test_when_finished rm -f trace*.txt &&
+ cat >bundle-list <<-EOF &&
+ [bundle]
+ version = 1
+ mode = all
+ heuristic = creationToken
+
+ [bundle "bundle-1"]
+ uri = file://$(pwd)/clone-from/bundle-1.bundle
+ creationToken = 1
+
+ [bundle "bundle-2"]
+ uri = file://$(pwd)/clone-from/bundle-2.bundle
+ creationToken = 2
+ EOF
+
+ GIT_TRACE_PACKET="$(pwd)/trace-packet.txt" \
+ git clone --no-local --single-branch --branch=left --no-tags \
+ --bundle-uri="file://$(pwd)/bundle-list" \
+ clone-from nego-bundle-list-all &&
+
+ git -C nego-bundle-list-all for-each-ref --format="%(refname)" >refs &&
+ grep "refs/bundles/" refs >actual &&
+ cat >expect <<-\EOF &&
+ refs/bundles/base
+ refs/bundles/left
+ EOF
+ test_cmp expect actual &&
+ # We already have all needed commits so no "want" needed.
+ ! grep "clone> want " trace-packet.txt
+'
+
#########################################################################
# HTTP tests begin here
base-commit: d8ab1d464d07baa30e5a180eb33b3f9aa5c93adf
--
gitgitgadget
