Re: [PATCH 2/4] rebase: avoid double reflog entry when switching branches

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 4, 2019, 18:38 UTC
Message-ID: <xmqqimz4cloh.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <4c5f87b9dc245bf27785aa5559d4b35d87c4bcbf.1545398254.git.gitgitgadget@gmail.com>

"Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com> writes:

Show 5 quoted lines

> From: Johannes Schindelin <johannes.schindelin@gmx.de>
>
> When switching a branch *and* updating said branch to a different
> revision, let's avoid a double entry by first updating the branch and
> then adjusting the symbolic ref HEAD.

Ah, in the original sequence, HEAD is updated twice, leaving two reflog entries for HEAD (and one for the underlying "switch_to" branch by virtue of REF_UPDATE_VIA_HEAD). In the new sequence, update_ref() updates the underlying "switch_to" and then HEAD, so we'd get one reflog entry for each of them.

Makes sense. s/let's avoid a double entry/& in HEAD's reflog/ would have avoided wasting reader's time who needlessly wondered where that redundancy came from, though.

Show 25 quoted lines

>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
>  builtin/rebase.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/builtin/rebase.c b/builtin/rebase.c
> index e1dfa74ca8..768bea0da8 100644
> --- a/builtin/rebase.c
> +++ b/builtin/rebase.c
> @@ -438,10 +438,11 @@ static int reset_head(struct object_id *oid, const char *action,
>  				 detach_head ? REF_NO_DEREF : 0,
>  				 UPDATE_REFS_MSG_ON_ERR);
>  	else {
> -		ret = create_symref("HEAD", switch_to_branch, msg.buf);
> +		ret = update_ref(reflog_orig_head, switch_to_branch, oid,
> +				 NULL, 0, UPDATE_REFS_MSG_ON_ERR);
>  		if (!ret)
> -			ret = update_ref(reflog_head, "HEAD", oid, NULL, 0,
> -					 UPDATE_REFS_MSG_ON_ERR);
> +			ret = create_symref("HEAD", switch_to_branch,
> +					    reflog_head);
>  	}
>  
>  leave_reset_head: