Subject: Re: [PATCH 2/2] status: don't say 'HEAD detached at HEAD'

From: Michael J Gruber <[email-masked]>
Date: Thu, 1 Oct 2015 13:13:19 +0200

Matthieu Moy venit, vidit, dixit 27.09.2015 17:13:
> After using "git checkout --detach", the reflog is left with an entry
> like
> 
>   checkout: moving from ... to HEAD
> 
> This message is parsed to generate the 'HEAD detached at' message in
> 'git branch' and 'git status', which leads to the not-so-useful message
> 'HEAD detached at HEAD'.
> 
> Instead, when parsing such reflog entry, resolve HEAD to the
> corresponding commit in the reflog, so that the message becomes 'HEAD
> detached at $sha1'.
> ---
> Another possible fix is to avoid creating such reflog entry. But
> anyway, this patch remains a good thing to do and it does fix the
> issue.
> 
> I won't have time to work on fixing the reflog soon, but it may be a
> nice microproject.
> 
>  t/t3203-branch-output.sh | 2 +-
>  wt-status.c              | 6 ++++++
>  2 files changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/t/t3203-branch-output.sh b/t/t3203-branch-output.sh
> index bf24dbf..16efe7a 100755
> --- a/t/t3203-branch-output.sh
> +++ b/t/t3203-branch-output.sh
> @@ -106,7 +106,7 @@ EOF
>  	test_i18ncmp expect actual
>  '
>  
> -test_expect_failure 'git branch shows detached HEAD properly after checkout --detach' '
> +test_expect_success 'git branch shows detached HEAD properly after checkout --detach' '
>  	git checkout master &&
>  	cat >expect <<EOF &&
>  * (HEAD detached at $(git rev-parse --short HEAD^0))
> diff --git a/wt-status.c b/wt-status.c
> index c327fe8..3e3b8c0 100644
> --- a/wt-status.c
> +++ b/wt-status.c
> @@ -1319,6 +1319,12 @@ static int grab_1st_switch(unsigned char *osha1, unsigned char *nsha1,
>  	hashcpy(cb->nsha1, nsha1);
>  	for (end = target; *end && *end != '\n'; end++)
>  		;
> +	if (!memcmp(target, "HEAD", end - target)) {
> +		/* HEAD is relative. Resolve it to the right reflog entry. */
> +		strbuf_addstr(&cb->buf,
> +			      find_unique_abbrev(nsha1, DEFAULT_ABBREV));
> +		return 1;
> +	}
>  	strbuf_add(&cb->buf, target, end - target);
>  	return 1;
>  }
> 

Reviewed and compile tested, thanks.

Junio will also want your s-o-by, though ;)

(Typically we don't introduce a failing test separately like 1/2 any
more and do it in 1 patch, but I don't care either way.)

Michael