On Mon, Nov 3, 2014 at 11:12 AM, Ronnie Sahlberg <sahlberg@xxxxxxxxxx> wrote:
> This adds support to send-pack to to negotiate and use atomic pushes
/s/to to/to/
> iff the server supports it. Atomic pushes are activated by a new command
> line flag --atomic-push.
>
> In order to do this we also need to change the semantics for send_pack()
> slightly. The existing send_pack() function actually don't sent all the
> refs back to the server when multiple refs are involved, for example
> when using --all. Several of the failure modes for pushes can already be
> detected locally in the send_pack client based on the information from the
> initial server side list of all the refs as generated by receive-pack.
> Any such refs that we thus know would fail to push are thus pruned from
> the list of refs we send to the server to update.
>
> For atomic pushes, we have to deal thus with both failures that are detected
> locally as well as failures that are reported back from the server. In order
> to do so we treat all local failures as push failures too.
>
> We introduce a new status code REF_STATUS_ATOMIC_PUSH_FAILED so we can
> flag all refs that we would normally have tried to push to the server
> but we did not due to local failures. This is to improve the error message
> back to the end user to flag that "these refs failed to update since the
> atomic push operation failed."
>
> Signed-off-by: Ronnie Sahlberg <sahlberg@xxxxxxxxxx>
> ---
> Documentation/git-send-pack.txt | 7 ++++++-
> builtin/send-pack.c | 6 +++++-
> remote.h | 3 ++-
> send-pack.c | 39 ++++++++++++++++++++++++++++++++++-----
> send-pack.h | 1 +
> transport.c | 4 ++++
> 6 files changed, 52 insertions(+), 8 deletions(-)
>
> diff --git a/Documentation/git-send-pack.txt b/Documentation/git-send-pack.txt
> index 2a0de42..9296587 100644
> --- a/Documentation/git-send-pack.txt
> +++ b/Documentation/git-send-pack.txt
> @@ -9,7 +9,7 @@ git-send-pack - Push objects over Git protocol to another repository
> SYNOPSIS
> --------
> [verse]
> -'git send-pack' [--all] [--dry-run] [--force] [--receive-pack=<git-receive-pack>] [--verbose] [--thin] [<host>:]<directory> [<ref>...]
> +'git send-pack' [--all] [--dry-run] [--force] [--receive-pack=<git-receive-pack>] [--verbose] [--thin] [--atomic-push] [<host>:]<directory> [<ref>...]
>
> DESCRIPTION
> -----------
> @@ -62,6 +62,11 @@ be in a separate packet, and the list must end with a flush packet.
> Send a "thin" pack, which records objects in deltified form based
> on objects not included in the pack to reduce network traffic.
>
> +--atomic-push::
> + Use an atomic transaction for updating the refs. If any of the refs
> + fails to update then the entire push will fail without changing any
> + refs.
> +
> <host>::
> A remote host to house the repository. When this
> part is specified, 'git-receive-pack' is invoked via
> diff --git a/builtin/send-pack.c b/builtin/send-pack.c
> index b564a77..93cb17c 100644
> --- a/builtin/send-pack.c
> +++ b/builtin/send-pack.c
> @@ -13,7 +13,7 @@
> #include "sha1-array.h"
>
> static const char send_pack_usage[] =
> -"git send-pack [--all | --mirror] [--dry-run] [--force] [--receive-pack=<git-receive-pack>] [--verbose] [--thin] [<host>:]<directory> [<ref>...]\n"
> +"git send-pack [--all | --mirror] [--dry-run] [--force] [--receive-pack=<git-receive-pack>] [--verbose] [--thin] [--atomic-push] [<host>:]<directory> [<ref>...]\n"
> " --all and explicit <ref> specification are mutually exclusive.";
>
> static struct send_pack_args args;
> @@ -170,6 +170,10 @@ int cmd_send_pack(int argc, const char **argv, const char *prefix)
> args.use_thin_pack = 1;
> continue;
> }
> + if (!strcmp(arg, "--atomic-push")) {
> + args.use_atomic_push = 1;
> + continue;
> + }
> if (!strcmp(arg, "--stateless-rpc")) {
> args.stateless_rpc = 1;
> continue;
> diff --git a/remote.h b/remote.h
> index 8b62efd..f346524 100644
> --- a/remote.h
> +++ b/remote.h
> @@ -115,7 +115,8 @@ struct ref {
> REF_STATUS_REJECT_SHALLOW,
> REF_STATUS_UPTODATE,
> REF_STATUS_REMOTE_REJECT,
> - REF_STATUS_EXPECTING_REPORT
> + REF_STATUS_EXPECTING_REPORT,
> + REF_STATUS_ATOMIC_PUSH_FAILED
> } status;
> char *remote_status;
> struct ref *peer_ref; /* when renaming */
> diff --git a/send-pack.c b/send-pack.c
> index 1ccc84c..08602a8 100644
> --- a/send-pack.c
> +++ b/send-pack.c
> @@ -190,7 +190,7 @@ static void advertise_shallow_grafts_buf(struct strbuf *sb)
> for_each_commit_graft(advertise_shallow_grafts_cb, sb);
> }
>
> -static int ref_update_to_be_sent(const struct ref *ref, const struct send_pack_args *args)
> +static int ref_update_to_be_sent(const struct ref *ref, const struct send_pack_args *args, int *atomic_push_failed)
> {
> if (!ref->peer_ref && !args->send_mirror)
> return 0;
> @@ -203,6 +203,12 @@ static int ref_update_to_be_sent(const struct ref *ref, const struct send_pack_a
> case REF_STATUS_REJECT_NEEDS_FORCE:
> case REF_STATUS_REJECT_STALE:
> case REF_STATUS_REJECT_NODELETE:
> + if (atomic_push_failed) {
> + fprintf(stderr, "Atomic push failed for ref %s. "
> + "Status:%d\n", ref->name, ref->status);
> + *atomic_push_failed = 1;
> + }
> + /* fallthrough */
> case REF_STATUS_UPTODATE:
> return 0;
> default:
> @@ -250,7 +256,7 @@ static int generate_push_cert(struct strbuf *req_buf,
> strbuf_addstr(&cert, "\n");
>
> for (ref = remote_refs; ref; ref = ref->next) {
> - if (!ref_update_to_be_sent(ref, args))
> + if (!ref_update_to_be_sent(ref, args, NULL))
> continue;
> update_seen = 1;
> strbuf_addf(&cert, "%s %s %s\n",
> @@ -297,7 +303,7 @@ int send_pack(struct send_pack_args *args,
> int atomic_push_supported = 0;
> int atomic_push = 0;
> unsigned cmds_sent = 0;
> - int ret;
> + int ret, atomic_push_failed = 0;
> struct async demux;
> const char *push_cert_nonce = NULL;
>
> @@ -332,6 +338,11 @@ int send_pack(struct send_pack_args *args,
> "Perhaps you should specify a branch such as 'master'.\n");
> return 0;
> }
> + if (args->use_atomic_push && !atomic_push_supported) {
> + fprintf(stderr, "Server does not support atomic-push.");
> + return -1;
> + }
> + atomic_push = atomic_push_supported && args->use_atomic_push;
>
> if (status_report)
> strbuf_addstr(&cap_buf, " report-status");
> @@ -365,7 +376,8 @@ int send_pack(struct send_pack_args *args,
> * the pack data.
> */
> for (ref = remote_refs; ref; ref = ref->next) {
> - if (!ref_update_to_be_sent(ref, args))
> + if (!ref_update_to_be_sent(ref, args,
> + args->use_atomic_push ? &atomic_push_failed : NULL))
> continue;
>
> if (!ref->deletion)
> @@ -377,6 +389,23 @@ int send_pack(struct send_pack_args *args,
> ref->status = REF_STATUS_EXPECTING_REPORT;
> }
>
> + if (atomic_push_failed) {
> + for (ref = remote_refs; ref; ref = ref->next) {
> + if (!ref->peer_ref && !args->send_mirror)
> + continue;
> +
> + switch (ref->status) {
> + case REF_STATUS_EXPECTING_REPORT:
> + ref->status = REF_STATUS_ATOMIC_PUSH_FAILED;
> + continue;
> + default:
> + ; /* do nothing */
> + }
> + }
> + fprintf(stderr, "Atomic push failed.");
> + return -1;
> + }
> +
> /*
> * Finally, tell the other end!
> */
> @@ -386,7 +415,7 @@ int send_pack(struct send_pack_args *args,
> if (args->dry_run || args->push_cert)
> continue;
>
> - if (!ref_update_to_be_sent(ref, args))
> + if (!ref_update_to_be_sent(ref, args, NULL))
> continue;
>
> old_hex = sha1_to_hex(ref->old_sha1);
> diff --git a/send-pack.h b/send-pack.h
> index 5635457..7486e65 100644
> --- a/send-pack.h
> +++ b/send-pack.h
> @@ -11,6 +11,7 @@ struct send_pack_args {
> force_update:1,
> use_thin_pack:1,
> use_ofs_delta:1,
> + use_atomic_push:1,
> dry_run:1,
> push_cert:1,
> stateless_rpc:1;
> diff --git a/transport.c b/transport.c
> index f70d62f..2111986 100644
> --- a/transport.c
> +++ b/transport.c
> @@ -731,6 +731,10 @@ static int print_one_push_status(struct ref *ref, const char *dest, int count, i
> ref->deletion ? NULL : ref->peer_ref,
> "remote failed to report status", porcelain);
> break;
> + case REF_STATUS_ATOMIC_PUSH_FAILED:
> + print_ref_status('!', "[rejected]", ref, ref->peer_ref,
> + "atomic-push-failed", porcelain);
> + break;
> case REF_STATUS_OK:
> print_ok_ref_status(ref, porcelain);
> break;
> --
> 2.1.0.rc2.206.gedb03e5
>
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