Re: [PATCH] transport-helper: enforce atomic in push_refs_with_push

[Junio C Hamano <gitster@pobox.com>]

Emily Shaffer <emilyshaffer@google.com> writes:

> diff --git a/transport-helper.c b/transport-helper.c
> index c7e17ec9cb..6b05a88faf 100644
> --- a/transport-helper.c
> +++ b/transport-helper.c
> @@ -853,6 +853,7 @@ static int push_refs_with_push(struct transport *transport,
>  {
>  	int force_all = flags & TRANSPORT_PUSH_FORCE;
>  	int mirror = flags & TRANSPORT_PUSH_MIRROR;
> +	int atomic = flags & TRANSPORT_PUSH_ATOMIC;
>  	struct helper_data *data = transport->data;
>  	struct strbuf buf = STRBUF_INIT;
>  	struct ref *ref;
> @@ -872,6 +873,11 @@ static int push_refs_with_push(struct transport *transport,
>  		case REF_STATUS_REJECT_NONFASTFORWARD:
>  		case REF_STATUS_REJECT_STALE:
>  		case REF_STATUS_REJECT_ALREADY_EXISTS:
> +			if (atomic) {
> +				string_list_clear(&cas_options, 0);
> +				return 0;
> +			} else
> +				continue;

Ah, this looks vaguely familiar.  Thanks for resurrecting the topic.

The clearing is merely to avoid leaks, and the primary change to the
function is to immediately return 0.

>  		case REF_STATUS_UPTODATE:
>  			continue;
>  		default:
> diff --git a/transport.c b/transport.c
> index f1fcd2c4b0..f4d6b38f9d 100644
> --- a/transport.c
> +++ b/transport.c
> @@ -1226,10 +1226,23 @@ int transport_push(struct repository *r,
>  		err = push_had_errors(remote_refs);
>  		ret = push_ret | err;

Here, before reporting the push result, when we are doing ATOMIC,
we tweak the result we are going to report to atomic-push-failed.

> +		if ((flags & TRANSPORT_PUSH_ATOMIC) && err) {
> +			for (struct ref *it = remote_refs; it; it = it->next)
> +				switch (it->status) {
> +				case REF_STATUS_NONE:
> +				case REF_STATUS_UPTODATE:
> +				case REF_STATUS_OK:
> +					it->status = REF_STATUS_ATOMIC_PUSH_FAILED;
> +				default:
> +					continue;
> +				}
> +		}

This roughly corresponds to what send-pack.c::atomic_push_failure()
does.  Here, we avoid overwriting a status that already signals a
failure.  The list of "good" statuses used here match what is used
at the end of send_pack.c::send_pack(), which decides the final
outcome of "git push" for the native transport.

Looks good.

By the way, I rearranged the patch as I happen to agree with Dscho
that the additional {} was unwarranted and made it harder to review.
It is clear that we need to tweak the status before reporting.

>
> 		if (!quiet || err)
>  			transport_print_push_status(transport->url, remote_refs,
>  					verbose | porcelain, porcelain,
>  					reject_reasons);
>  
>  		if (flags & TRANSPORT_PUSH_SET_UPSTREAM)
>  			set_upstreams(transport, remote_refs, pretend);