From: Junio C Hamano <gitster@pobox.com>
Date: Fri, 30 Jan 2015 20:32:07 GMT
Subject: Re: [PATCH] apply: refuse touching a file beyond symlink
Message-ID: <xmqqsiesau2g.fsf@gitster.dls.corp.google.com>
In-Reply-To: <20150130200731.GC30738@peff.net>

Jeff King <peff@peff.net> writes:

> Hrm. That only works in the current code because we apply the deletion
> in the directory (and then clean up the now-empty directory) first. So I
> think you would need to check the paths progressively as you apply them,
> since those other parts of the diff "haven't happened yet".

Just to make sure that I am not hallucinating, I added this one:

diff --git a/t/t4114-apply-typechange.sh b/t/t4114-apply-typechange.sh
index ebadbc3..83ddf62 100755
--- a/t/t4114-apply-typechange.sh
+++ b/t/t4114-apply-typechange.sh
@@ -119,4 +119,12 @@ test_expect_success 'directory becomes symlink' '
 test_debug 'cat patch'
 
 
+test_expect_success 'directory becomes symlink' '
+	git checkout -f foo-becomes-a-directory &&
+	printf "%s\n" foo/baz foo >order &&
+	git diff-tree -Oorder -p HEAD foo-symlinked-to-bar >patch &&
+	git apply --index <patch
+	'
+test_debug 'cat patch'
+
 test_done

It is a copy of the original, only forcing the patches in the input
in the opposite order.

Having said that and also having read your two-phase internal
application change, I think that two-phase thing is probably a good
way to go (we may even want to ignore "previous_patch()" stuff, as
its "was_deleted()" and "tobe_deleted()" are all about "force the
application of a later patch to depend on the result of application
of an earlier patch").