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From: Eric Sunshine <sunshine@sunshineco.com>
To: Stefan Beller <sbeller@google.com>
Cc: ronnie sahlberg <ronniesahlberg@gmail.com>,
	Michael Haggerty <mhagger@alum.mit.edu>,
	Jonathan Nieder <jrnieder@gmail.com>,
	Junio C Hamano <gitster@pobox.com>,
	Git List <git@vger.kernel.org>
Subject: Re: [PATCHv8 6/9] receive-pack.c: add execute_commands_atomic function
Date: Tue, 30 Dec 2014 03:57:52 -0500	[thread overview]
Message-ID: <CAPig+cTY3UQsOEut7mqUze1or1i3Hx9=2inrToOFrRKEo08=XQ@mail.gmail.com> (raw)
In-Reply-To: <1419907007-19387-7-git-send-email-sbeller@google.com>

On Mon, Dec 29, 2014 at 9:36 PM, Stefan Beller <sbeller@google.com> wrote:
> Update receive-pack to use an atomic transaction iff the client negotiated
> that it wanted atomic push.

This first line seems germane to this patch...

> This leaves the default behavior to be the old
> non-atomic one ref at a time update. This is to cause as little disruption
> as possible to existing clients. It is unknown if there are client scripts
> that depend on the old non-atomic behavior so we make it opt-in for now.
>
> If it turns out over time that there are no client scripts that depend on the
> old behavior we can change git to default to use atomic pushes and instead
> offer an opt-out argument for people that do not want atomic pushes.

However, the remainder feels like it belongs with some other patch,
such as a patch which introduces an --atomic option.

> Inspired-by: Ronnie Sahlberg <sahlberg@google.com>
> Helped-by: Eric Sunshine <sunshine@sunshineco.com>
> Signed-off-by: Stefan Beller <sbeller@google.com>
> ---
> diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
> index 5f44466..35a2264 100644
> --- a/builtin/receive-pack.c
> +++ b/builtin/receive-pack.c
> @@ -1076,8 +1076,8 @@ static void check_shallow_bugs(struct command *commands,
>                       "the reported refs above");
>  }
>
> -static void execute_commands_loop(struct command *commands,
> -                                 struct shallow_info *si)
> +static void execute_commands_non_atomic(struct command *commands,
> +                                       struct shallow_info *si)

Style: Indent the wrapped line to align with the text following the
'(' in the first line.

>  {
>         struct command *cmd;
>         struct strbuf err = STRBUF_INIT;
> @@ -1104,7 +1104,50 @@ static void execute_commands_loop(struct command *commands,
>                 }
>                 ref_transaction_free(transaction);
>         }
> +       strbuf_release(&err);
> +}
> +
> +static void execute_commands_atomic(struct command *commands,
> +                                       struct shallow_info *si)

Style: Indentation.

> +{
> +       struct command *cmd;
> +       struct strbuf err = STRBUF_INIT;
> +       const char *reported_error = "atomic push failure";
> +
> +       transaction = ref_transaction_begin(&err);
> +       if (!transaction) {
> +               rp_error("%s", err.buf);
> +               strbuf_reset(&err);
> +               reported_error = "transaction failed to start";
> +               goto failure;
> +       }
> +
> +       for (cmd = commands; cmd; cmd = cmd->next) {
> +               if (!should_process_cmd(cmd))
> +                       continue;
>
> +               cmd->error_string = update(cmd, si);
> +
> +               if (cmd->error_string)
> +                       goto failure;
> +       }
> +
> +       if (ref_transaction_commit(transaction, &err)) {
> +               rp_error("%s", err.buf);
> +               reported_error = "atomic transaction failed";
> +               goto failure;
> +       }
> +
> +       ref_transaction_free(transaction);
> +       strbuf_release(&err);
> +       return;

Minor comment: This cleanup code is repeated in both the success and
fail branches. It _might_ (or not) be a bit cleaner and more
maintainable to replace the above three lines with:

    goto done;

> +
> +failure:
> +       for (cmd = commands; cmd; cmd = cmd->next)
> +               if (!cmd->error_string)
> +                       cmd->error_string = reported_error;

And add a 'done' label here:

    done:

> +       ref_transaction_free(transaction);
>         strbuf_release(&err);
>  }
>
> @@ -1142,7 +1185,10 @@ static void execute_commands(struct command *commands,
>         free(head_name_to_free);
>         head_name = head_name_to_free = resolve_refdup("HEAD", 0, sha1, NULL);
>
> -       execute_commands_loop(commands, si);
> +       if (use_atomic)
> +               execute_commands_atomic(commands, si);
> +       else
> +               execute_commands_non_atomic(commands, si);
>
>         check_shallow_bugs(commands, si);
>  }
> --
> 2.2.1.62.g3f15098

  reply	other threads:[~2014-12-30  8:58 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-30  2:36 [PATCHv8 0/9] atomic pushes Stefan Beller
2014-12-30  2:36 ` [PATCHv8 1/9] receive-pack.c: add documentation for atomic push support Stefan Beller
2014-12-30  7:08   ` Eric Sunshine
2014-12-30  8:33     ` Stefan Beller
2014-12-30  9:09       ` Eric Sunshine
2014-12-30  2:36 ` [PATCHv8 2/9] send-pack: rename ref_update_to_be_sent to check_to_send_update Stefan Beller
2014-12-30  2:36 ` [PATCHv8 3/9] send-pack.c: add --atomic command line argument Stefan Beller
2014-12-30  2:36 ` [PATCHv8 4/9] receive-pack.c: simplify execute_commands Stefan Beller
2014-12-30  6:11   ` Eric Sunshine
2014-12-30  8:41     ` Stefan Beller
2014-12-30 20:33     ` Stefan Beller
2014-12-30 21:15       ` Eric Sunshine
2014-12-30  7:46   ` Eric Sunshine
2014-12-30  8:42     ` Stefan Beller
2014-12-30  9:10       ` Eric Sunshine
2014-12-30  2:36 ` [PATCHv8 5/9] receive-pack.c: move transaction handling in a central place Stefan Beller
2014-12-30  8:36   ` Eric Sunshine
2014-12-30 18:45     ` Stefan Beller
2014-12-30 20:33       ` Eric Sunshine
2014-12-30  2:36 ` [PATCHv8 6/9] receive-pack.c: add execute_commands_atomic function Stefan Beller
2014-12-30  8:57   ` Eric Sunshine [this message]
2014-12-30  2:36 ` [PATCHv8 7/9] receive-pack.c: enable atomic push protocol support Stefan Beller
2014-12-30  2:36 ` [PATCHv8 8/9] push.c: add an --atomic argument Stefan Beller
2014-12-30  2:36 ` [PATCHv8 9/9] t5543-atomic-push.sh: add basic tests for atomic pushes Stefan Beller

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