From: Junio C Hamano <gitster@pobox.com>
Date: Fri, 04 May 2012 19:51:28 GMT
Subject: Re: [PATCH 2/2] checkout (detached): truncate list of orphaned commits at the new HEAD
Message-ID: <7vaa1nafnj.fsf@alter.siamese.dyndns.org>
In-Reply-To: <4FA41C98.2010105@kdbg.org>

Johannes Sixt <j6t@kdbg.org> writes:

> When git checkout switches from a detached HEAD to any other commit, then
> all orphaned commits were listed in a warning:
>
>   Warning: you are leaving 2 commits behind...:
>
>     a5e5396 another fixup
>     6aa1af6 fixup foo
>
> But if the new commit is actually one from this list (6aa1af6 in this
> example), then the list in the warning can be truncated at the new HEAD,
> because history beginning at HEAD is not "left behind". This makes it so.

If you did:

	git checkout master^0
        git commit --allow-empty -m emp0
        git commit --allow-empty -m emp1
        tip=$(git rev-parse HEAD)
        git reset --hard HEAD^

and then

	git checkout $tip

it used to warn about "emp0" but because you are checking out "emp1",
which is a descendant of "emp0", nothing is lost and no lossage is
reported with the updated code.

Makes sense; thanks.