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From: Karthik Nayak <karthik.188@gmail.com>
To: blanet via GitGitGadget <gitgitgadget@gmail.com>, git@vger.kernel.org
Cc: blanet <bupt_xingxin@163.com>, Xing Xin <xingxin.xx@bytedance.com>
Subject: Re: [PATCH v2] bundle-uri: verify oid before writing refs
Date: Tue, 21 May 2024 15:41:40 +0000	[thread overview]
Message-ID: <CAOLa=ZR2QU-76ovpMF4xRvAzY447ce+oAYCaiiMTcFGL7Q52-A@mail.gmail.com> (raw)
In-Reply-To: <pull.1730.v2.git.1716208605926.gitgitgadget@gmail.com>

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"blanet via GitGitGadget" <gitgitgadget@gmail.com> writes:

> From: Xing Xin <xingxin.xx@bytedance.com>
>
> 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

s/bacause/because

[snip]

> 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

This update looks good to me, Thanks.

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  reply	other threads:[~2024-05-21 15:41 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-15  3:01 [PATCH] bundle-uri: refresh packed_git if unbundle succeed blanet via GitGitGadget
2024-05-17  5:00 ` Patrick Steinhardt
2024-05-17 16:14   ` Junio C Hamano
2024-05-20 11:48     ` Xing Xin
2024-05-20 17:19       ` Junio C Hamano
2024-05-27 16:04         ` Xing Xin
2024-05-20  9:41   ` Xing Xin
2024-05-17  7:36 ` Karthik Nayak
2024-05-20 10:19   ` Xing Xin
2024-05-20 12:36 ` [PATCH v2] bundle-uri: verify oid before writing refs blanet via GitGitGadget
2024-05-21 15:41   ` Karthik Nayak [this message]
2024-05-27 15:41   ` [PATCH v3 0/4] object checking related additions and fixes for bundles in fetches blanet via GitGitGadget
2024-05-27 15:41     ` [PATCH v3 1/4] bundle-uri: verify oid before writing refs Xing Xin via GitGitGadget
2024-05-28 11:55       ` Patrick Steinhardt
2024-05-30  8:32         ` Xing Xin
2024-05-27 15:41     ` [PATCH v3 2/4] unbundle: introduce unbundle_fsck_flags for fsckobjects handling Xing Xin via GitGitGadget
2024-05-28 12:03       ` Patrick Steinhardt
2024-05-29 18:12         ` Xing Xin
2024-05-30  4:38           ` Patrick Steinhardt
2024-05-30  8:46             ` Xing Xin
2024-05-27 15:41     ` [PATCH v3 3/4] fetch-pack: expose fsckObjects configuration logic Xing Xin via GitGitGadget
2024-05-28 12:03       ` Patrick Steinhardt
2024-05-28 17:10         ` Junio C Hamano
2024-05-28 17:24           ` Junio C Hamano
2024-05-29  5:52             ` Patrick Steinhardt
2024-05-30  8:48             ` Xing Xin
2024-05-29  5:52           ` Patrick Steinhardt
2024-05-27 15:41     ` [PATCH v3 4/4] unbundle: introduce new option UNBUNDLE_FSCK_FOLLOW_FETCH Xing Xin via GitGitGadget
2024-05-28 12:05       ` Patrick Steinhardt
2024-05-30  8:54         ` Xing Xin
2024-05-30  8:21     ` [PATCH v4 0/4] object checking related additions and fixes for bundles in fetches blanet via GitGitGadget
2024-05-30  8:21       ` [PATCH v4 1/4] bundle-uri: verify oid before writing refs Xing Xin via GitGitGadget
2024-05-30  8:21       ` [PATCH v4 2/4] unbundle: extend verify_bundle_flags to support fsck-objects Xing Xin via GitGitGadget
2024-06-06 12:06         ` Patrick Steinhardt
2024-06-11  6:46           ` Xing Xin
2024-05-30  8:21       ` [PATCH v4 3/4] fetch-pack: expose fsckObjects configuration logic Xing Xin via GitGitGadget
2024-05-30  8:21       ` [PATCH v4 4/4] unbundle: introduce option VERIFY_BUNDLE_FSCK_FOLLOW_FETCH Xing Xin via GitGitGadget
2024-06-06 12:06         ` Patrick Steinhardt
2024-06-11  6:46           ` Xing Xin
2024-06-11  6:42       ` [PATCH v5 0/4] object checking related additions and fixes for bundles in fetches blanet via GitGitGadget
2024-06-11  6:42         ` [PATCH v5 1/4] bundle-uri: verify oid before writing refs Xing Xin via GitGitGadget
2024-06-11  6:42         ` [PATCH v5 2/4] fetch-pack: expose fsckObjects configuration logic Xing Xin via GitGitGadget
2024-06-11  6:42         ` [PATCH v5 3/4] unbundle: extend options to support object verification Xing Xin via GitGitGadget
2024-06-11  9:11           ` Patrick Steinhardt
2024-06-11 12:47             ` Xing Xin
2024-06-11  6:42         ` [PATCH v5 4/4] unbundle: use VERIFY_BUNDLE_FSCK_FOLLOW_FETCH for fetches Xing Xin via GitGitGadget
2024-06-11 12:45         ` [PATCH v6 0/3] object checking related additions and fixes for bundles in fetches blanet via GitGitGadget
2024-06-11 12:45           ` [PATCH v6 1/3] bundle-uri: verify oid before writing refs Xing Xin via GitGitGadget
2024-06-11 19:08             ` Junio C Hamano
2024-06-17 13:53               ` Xing Xin
2024-06-11 12:45           ` [PATCH v6 2/3] fetch-pack: expose fsckObjects configuration logic Xing Xin via GitGitGadget
2024-06-11 19:20             ` Junio C Hamano
2024-06-11 12:45           ` [PATCH v6 3/3] unbundle: support object verification for fetches Xing Xin via GitGitGadget
2024-06-11 20:05             ` Junio C Hamano
2024-06-12 18:33               ` Xing Xin
2024-06-11 13:14           ` [PATCH v6 0/3] object checking related additions and fixes for bundles in fetches Patrick Steinhardt
2024-06-17 13:55           ` [PATCH v7 " blanet via GitGitGadget
2024-06-17 13:55             ` [PATCH v7 1/3] bundle-uri: verify oid before writing refs Xing Xin via GitGitGadget
2024-06-18 17:37               ` Junio C Hamano
2024-06-19  6:30                 ` Xing Xin
2024-06-17 13:55             ` [PATCH v7 2/3] fetch-pack: expose fsckObjects configuration logic Xing Xin via GitGitGadget
2024-06-17 13:55             ` [PATCH v7 3/3] unbundle: extend object verification for fetches Xing Xin via GitGitGadget
2024-06-19  4:07             ` [PATCH v8 0/3] object checking related additions and fixes for bundles in fetches blanet via GitGitGadget
2024-06-19  4:07               ` [PATCH v8 1/3] bundle-uri: verify oid before writing refs Xing Xin via GitGitGadget
2024-06-19  4:07               ` [PATCH v8 2/3] fetch-pack: expose fsckObjects configuration logic Xing Xin via GitGitGadget
2024-06-19  4:07               ` [PATCH v8 3/3] unbundle: extend object verification for fetches Xing Xin via GitGitGadget

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