Re: [RFC 1/3] sequencer: Signal failed ff as an aborted, not a conflicted merge
- From
Fabian Ruch <bafain@gmail.com>
- Date
- Jun 9, 2014, 15:04 UTC
- Message-ID
- <5395CD04.2050303@gmail.com>
- In-Reply-To
- <xmqqvbsrf4hd.fsf@gitster.dls.corp.google.com>
Hi Junio,
On 05/27/2014 08:42 PM, Junio C Hamano wrote:
Show 10 quoted lines
> 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).
Kind regards, Fabian
-- >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));
-- 2.0.0