From: Arturas Moskvinas <arturas@uber.com>
To: jonathantanmy@google.com
Cc: git@vger.kernel.org
Subject: Re: [PATCH] upload-pack: clear flags before each v2 request
Date: Wed, 17 Oct 2018 15:05:17 +0300 [thread overview]
Message-ID: <CAGY-PBiH1fKebjgCfrcCTpC9Xue7guqYoE51UpBQJ30zJoxGeQ@mail.gmail.com> (raw)
In-Reply-To: <20181016215850.47821-1-jonathantanmy@google.com>
Hello,
I can confirm that shallow clones are no longer failing.
--
Arturas Moskvinas
On Wed, Oct 17, 2018 at 12:58 AM Jonathan Tan <jonathantanmy@google.com> wrote:
>
> Suppose a server has the following commit graph:
>
> A B
> \ /
> O
>
> We create a client by cloning A from the server with depth 1, and add
> many commits to it (so that future fetches span multiple requests due to
> lengthy negotiation). If it then fetches B using protocol v2, the fetch
> spanning multiple requests, the resulting packfile does not contain O
> even though the client did report that A is shallow.
>
> This is because upload_pack_v2() can be called multiple times while
> processing the same session. During the 2nd and all subsequent
> invocations, some object flags remain from the previous invocations. In
> particular, CLIENT_SHALLOW remains, preventing process_shallow() from
> adding client-reported shallows to the "shallows" array, and hence
> pack-objects not knowing about these client-reported shallows.
>
> Therefore, teach upload_pack_v2() to clear object flags at the start of
> each invocation.
>
> (One alternative is to reduce or eliminate usage of object flags in
> protocol v2, but that doesn't seem feasible because almost all 8 flags
> are used pervasively in v2 code.)
>
> Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
> ---
> This was noticed by Arturas Moskvinas <arturas@uber.com> in [1]. The
> reproduction steps given were to repeat a shallow fetch twice in
> succession, but I found it easier to write a more understandable test if
> I made the 2nd fetch an ordinary fetch. In any case, I also reran the
> original reproduction steps, and the fetch completes without error.
>
> This patch doesn't cover the negotiation issue that I mentioned in my
> previous reply [2].
>
> [1] https://public-inbox.org/git/CAGY-PBgsG-T3JY=awszwGMpFx+jDx-a1FcV0s6vR067bSqgZaA@mail.gmail.com/
> [2] https://public-inbox.org/git/20181013004356.257709-1-jonathantanmy@google.com/
> ---
> t/t5702-protocol-v2.sh | 25 +++++++++++++++++++++++++
> upload-pack.c | 5 +++++
> 2 files changed, 30 insertions(+)
>
> diff --git a/t/t5702-protocol-v2.sh b/t/t5702-protocol-v2.sh
> index 88a886975d..70b88385ba 100755
> --- a/t/t5702-protocol-v2.sh
> +++ b/t/t5702-protocol-v2.sh
> @@ -429,6 +429,31 @@ test_expect_success 'fetch supports include-tag and tag following' '
> git -C client cat-file -e $(git -C client rev-parse annotated_tag)
> '
>
> +test_expect_success 'upload-pack respects client shallows' '
> + rm -rf server client trace &&
> +
> + git init server &&
> + test_commit -C server base &&
> + test_commit -C server client_has &&
> +
> + git clone --depth=1 "file://$(pwd)/server" client &&
> +
> + # Add extra commits to the client so that the whole fetch takes more
> + # than 1 request (due to negotiation)
> + for i in $(seq 1 32)
> + do
> + test_commit -C client c$i
> + done &&
> +
> + git -C server checkout -b newbranch base &&
> + test_commit -C server client_wants &&
> +
> + GIT_TRACE_PACKET="$(pwd)/trace" git -C client -c protocol.version=2 \
> + fetch origin newbranch &&
> + # Ensure that protocol v2 is used
> + grep "git< version 2" trace
> +'
> +
> # Test protocol v2 with 'http://' transport
> #
> . "$TEST_DIRECTORY"/lib-httpd.sh
> diff --git a/upload-pack.c b/upload-pack.c
> index 62a1000f44..de7de1de38 100644
> --- a/upload-pack.c
> +++ b/upload-pack.c
> @@ -37,6 +37,9 @@
> #define CLIENT_SHALLOW (1u << 18)
> #define HIDDEN_REF (1u << 19)
>
> +#define ALL_FLAGS (THEY_HAVE | OUR_REF | WANTED | COMMON_KNOWN | SHALLOW | \
> + NOT_SHALLOW | CLIENT_SHALLOW | HIDDEN_REF)
> +
> static timestamp_t oldest_have;
>
> static int deepen_relative;
> @@ -1393,6 +1396,8 @@ int upload_pack_v2(struct repository *r, struct argv_array *keys,
> enum fetch_state state = FETCH_PROCESS_ARGS;
> struct upload_pack_data data;
>
> + clear_object_flags(ALL_FLAGS);
> +
> git_config(upload_pack_config, NULL);
>
> upload_pack_data_init(&data);
> --
> 2.19.0.271.gfe8321ec05.dirty
>
next prev parent reply other threads:[~2018-10-17 12:05 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-16 21:58 [PATCH] upload-pack: clear flags before each v2 request Jonathan Tan
2018-10-17 12:05 ` Arturas Moskvinas [this message]
2018-10-18 5:16 ` Junio C Hamano
2018-10-18 20:43 ` [PATCH v2 0/3] Clear " Jonathan Tan
2018-10-18 20:43 ` [PATCH v2 1/3] upload-pack: make have_obj not global Jonathan Tan
2018-10-18 20:43 ` [PATCH v2 2/3] upload-pack: make want_obj " Jonathan Tan
2018-10-18 20:43 ` [PATCH v2 3/3] upload-pack: clear flags before each v2 request Jonathan Tan
2018-10-19 3:19 ` [PATCH v2 0/3] Clear " Junio C Hamano
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