Re: [PATCH 06/11] reset_head(): make default_reflog_action optional

From: Junio C Hamano <gitster@pobox.com>
Date: Oct 1, 2021, 21:08 UTC
Message-ID: <xmqqczoo5u7m.fsf@gitster.g>
In-Reply-To: <4503defe5912aecc4e6a50ac82a31aa7b230456b.1633082702.git.gitgitgadget@gmail.com>

"Phillip Wood via GitGitGadget" <gitgitgadget@gmail.com> writes:

Show 7 quoted lines

> From: Phillip Wood <phillip.wood@dunelm.org.uk>
>
> This parameter is only needed when a ref is going to be updated and
> the caller does not pass an explicit reflog message. Callers that are
> just discarding changes in the working tree like create_autostash() do
> not update any refs so should not have to worry about passing this
> parameter.

This only talks about internal implementation details of passing a parameter that may not be used, but ...

Show 6 quoted lines

> -	ret = update_refs(oid, switch_to_branch, reflog_head, reflog_orig_head,
> -			  default_reflog_action, flags);
> +	if (oid != &head_oid || update_orig_head || switch_to_branch)
> +		ret = update_refs(oid, switch_to_branch, reflog_head,
> +				  reflog_orig_head, default_reflog_action,
> +				  flags);

... doesn't this have a more significant behaviour change?

I am not sure if comparison between oid and head_oid can safely cheat like the patch does, or if it is necessary to do a proper oid comparison, but either way, this would stop calling update_refs(), which in turn means it would have an externally visible effect, like a hook no longer getting called, doesn't it?

It would be a change for the good---calling post-checkout hook when you did "git checkout (no other arguments)" feels wasteful, but it deserves to be told to end users, I would think.

Again, a new test to protect the change would go well in the same patch.

Thanks.