From: Joshua Hudson <jhudson@cedaron.com>
Date: Tue, 27 Jun 2023 13:43:38 GMT
Subject: Re: [PATCH] ll-merge: killing the external merge driver aborts the merge
Message-ID: <45ca0983-a0b6-1372-b548-2e0351988587@cedaron.com>
In-Reply-To: <59b7a582-be68-3f7b-a06f-3bd662582a1d@gmx.de>


On 6/27/2023 5:02 AM, Johannes Schindelin wrote:
> Hi,
>
>
> On Fri, 23 Jun 2023, Junio C Hamano wrote:
>
>> Junio C Hamano <gitster@pobox.com> writes:
>>
>>> Elijah Newren <newren@gmail.com> writes:
>>>
>>>> Reviewed-by: Elijah Newren <newren@gmail.com>
>>>
>>> Thanks for a quick review.
>> Unfortunately Windows does not seem to correctly detect the aborting
>> merge driver.  Does run_command() there report process death due to
>> signals differently, I wonder?
>>
>> https://github.com/git/git/actions/runs/5360400800/jobs/9725341775#step:6:285
>>
>> shows that on Windows, aborted external merge driver is not noticed
>> and we happily take the auto-merged result, ouch.
> Hmm. I tried to verify this, but failed. With this patch:
>
> ```diff
> diff --git a/git.c b/git.c
> index 2f42da20f4e0..3c513e3f2cb1 100644
> --- a/git.c
> +++ b/git.c
> @@ -330,6 +330,8 @@ static int handle_options(const char ***argv, int *argc, int *envchanged)
>   			setenv(GIT_ATTR_SOURCE_ENVIRONMENT, cmd, 1);
>   			if (envchanged)
>   				*envchanged = 1;
> +		} else if (!strcmp(cmd, "--abort")) {
> +			abort();
>   		} else {
>   			fprintf(stderr, _("unknown option: %s\n"), cmd);
>   			usage(git_usage_string);
> ```
>
> I get this:
>
>
> ```console
> $ ./git.exe --abort
>
> $ echo $?
> 3
> ```
>
> For that reason, I am somehow doubtful that the `abort()` is actually
> called?!?
>
> Ciao,
> Johannes

abort(); does _exit(3); on Windows because there are no signals. This is 
easily changed by providing abort like so:

void abort() { _exit(131 /* or whatever else you think goes here */); }