From: Junio C Hamano <gitster@pobox•com>
To: Fabian Ruch <bafain@gmail•com>
Cc: git@vger•kernel.org, Phil Hord <hordp@cisco•com>
Subject: Re: [RFC 1/3] sequencer: Signal failed ff as an aborted, not a conflicted merge
Date: Tue, 10 Jun 2014 10:56:44 -0700 [thread overview]
Message-ID: <xmqq8up4abs3.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <5395CD04.2050303@gmail.com> (Fabian Ruch's message of "Mon, 09 Jun 2014 17:04:36 +0200")
Fabian Ruch <bafain@gmail•com> writes:
> On 05/27/2014 08:42 PM, Junio C Hamano wrote:
>> Fabian Ruch <bafain@gmail•com> writes:
>>> [..]
>>>
>>> In order to signal the three possible situations (not only success and
>>> failure to complete) after a pick through porcelain commands such as
>>> `cherry-pick`, exit with a return value that is neither 0 nor 1. -1 was
>>> chosen in line with the other situations in which the sequencer
>>> encounters an error.
>>
>> Hmph... do we still pass negative to exit() anywhere in our codebase?
>
> No, but I thought `cmd_cherry_pick` would just forward the `return -1` from the
> sequencer to the shell. I had another look and found that `cmd_cherry_pick`
> calls `die` instead. Now, the commit inserts 128 as exit status in
> `fast_forward_to`.
>
> Would it be appropriate to mention the choice of exit status in the coding
> guidelines? I didn't know that the int-argument to exit(3) gets truncated and
> that this is why it is a general rule to only use values in the range from 0 to
> 255 with exit(3).
I personally do not think of a reason why it is necessary to mention
how the argument to exit(3) is expected to be used by the system, but
if it is common not to know it, I guess it would not hurt to have a
single paragraph with at most two lines.
In any case, I agree that exiting with 1 that signals "failed with
conflict" can be confusing to the caller. Can we have a test to
demonstrate when this fix matters?
Thanks.
> -- >8 --
> Subject: sequencer: Signal failed ff as an aborted, not a conflicted merge
>
> `do_pick_commit` handles three situations if it is not fast-forwarding.
> In order for `do_pick_commit` to identify the situation, it examines the
> return value of the selected merge command.
>
> 1. return value 0 stands for a clean merge
> 2. 1 is passed in case of a failed merge due to conflict
> 3. any other return value means that the merge did not even start
>
> So far, the sequencer returns 1 in case of a failed fast-forward, which
> would mean "failed merge due to conflict". However, a fast-forward
> either starts and succeeds or does not start at all. In particular, it
> cannot fail in between like a merge with a dirty index due to conflicts.
>
> In order to signal the three possible situations (not only success and
> failure to complete) after a pick through porcelain commands such as
> `cherry-pick`, exit with a return value that is neither 0 nor 1. 128 was
> chosen in line with the other situations in which the sequencer
> encounters an error. In such situations, the sequencer returns a
> negative value and `cherry-pick` translates this into a call to `die`.
> `die` then terminates the process with exit status 128.
>
> Signed-off-by: Fabian Ruch <bafain@gmail•com>
> ---
> sequencer.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/sequencer.c b/sequencer.c
> index 90cac7b..225afcb 100644
> --- a/sequencer.c
> +++ b/sequencer.c
> @@ -278,7 +278,7 @@ static int fast_forward_to(const unsigned char *to, const unsigned char *from,
>
> read_cache();
> if (checkout_fast_forward(from, to, 1))
> - exit(1); /* the callee should have complained already */
> + exit(128); /* the callee should have complained already */
> ref_lock = lock_any_ref_for_update("HEAD", unborn ? null_sha1 : from,
> 0, NULL);
> strbuf_addf(&sb, "%s: fast-forward", action_name(opts));
next prev parent reply other threads:[~2014-06-10 17:56 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-02 22:37 git-rebase-todo gets popped prematurely Phil Hord
2014-05-26 22:19 ` [RFC 1/3] sequencer: Signal failed ff as an aborted, not a conflicted merge Fabian Ruch
2014-05-27 18:42 ` Junio C Hamano
2014-06-09 15:04 ` Fabian Ruch
2014-06-10 17:56 ` Junio C Hamano [this message]
2014-06-10 18:51 ` Phil Hord
2014-06-10 19:17 ` Junio C Hamano
2014-05-26 22:19 ` [RFC 2/3] rebase -i: Reschedule tasks that failed before the index was touched Fabian Ruch
2014-05-27 11:56 ` Michael Haggerty
2014-05-27 18:26 ` Phil Hord
2014-05-26 22:19 ` [RFC 3/3] tests: Add 'rebase -i commits that overwrite untracked files' Fabian Ruch
2014-05-27 13:15 ` Michael Haggerty
2014-05-27 18:47 ` Junio C Hamano
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