[PATCH] difftool: avoid symlinks when reusing worktree files

[David Aguilar <davvid@gmail.com>]

difftool's dir-diff should never reuse a symlink, regardless of
what it points to.  Tighten use_wt_file() so that it rejects all
symlinks.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: David Aguilar <davvid@gmail.com>
---
 git-difftool.perl | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/git-difftool.perl b/git-difftool.perl
index 1abe647..873db57 100755
--- a/git-difftool.perl
+++ b/git-difftool.perl
@@ -70,13 +70,13 @@ sub use_wt_file
 	my ($repo, $workdir, $file, $sha1) = @_;
 	my $null_sha1 = '0' x 40;
 
-	if (! -f "$workdir/$file") {
-		return (0, $null_sha1);
+	my $workfile = "$workdir/$file";
+	if (-f $workfile && ! -l $workfile) {
+		my $wt_sha1 = $repo->command_oneline('hash-object', $workfile);
+		my $use = ($sha1 eq $null_sha1) || ($sha1 eq $wt_sha1);
+		return ($use, $wt_sha1);
 	}
-
-	my $wt_sha1 = $repo->command_oneline('hash-object', "$workdir/$file");
-	my $use = ($sha1 eq $null_sha1) || ($sha1 eq $wt_sha1);
-	return ($use, $wt_sha1);
+	return (0, $null_sha1);
 }
 
 sub changed_files
-- 
2.6.2.282.gfefd36e