[PATCH 1/2] difftool: only copy back files modified during directory diff

[Tim Henigan <tim.henigan@gmail.com>]

When 'difftool --dir-diff' is used to compare working tree files,
it always copies files from the tmp dir back to the working tree
when the diff tool is closed, even if the files were not modified
by the diff tool.

This causes the file timestamp to change. Files should only be
copied from the tmp dir back to the working copy if they were
actually modified.

Signed-off-by: Tim Henigan <tim.henigan@gmail.com>
---

This patch must be applied after commit 304970d on next (diff-no-index:
exit(1) if 'diff --quiet <repo file> <external file>' finds changes).
because it relies on 'git diff --quiet' to compare files outside the
repository.


 git-difftool.perl | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/git-difftool.perl b/git-difftool.perl
index ae1e052..679a56d 100755
--- a/git-difftool.perl
+++ b/git-difftool.perl
@@ -336,8 +336,11 @@ if (defined($dirdiff)) {
 	# files were modified during the diff, then the changes
 	# should be copied back to the working tree
 	for my $file (@working_tree) {
-		copy("$b/$file", "$workdir/$file") or die $!;
-		chmod(stat("$b/$file")->mode, "$workdir/$file") or die $!;
+		if ((-e "$b/$file") &&
+		    (system('git', 'diff', '--quiet', "$b/$file", "$workdir/$file") != 0)) {
+			copy("$b/$file", "$workdir/$file") or die $!;
+			chmod(stat("$b/$file")->mode, "$workdir/$file") or die $!;
+		}
 	}
 } else {
 	if (defined($prompt)) {
-- 
1.7.11.1.134.gda62046