Merge branch 'ks/difftool-dir-diff-copy-fix' into maint

* ks/difftool-dir-diff-copy-fix:
  difftool --dir-diff: allow changing any clean working tree file

Author: gitster

git-difftool.perl

@@ -85,13 +85,9 @@ sub exit_cleanup
 
 sub use_wt_file
 {
-	my ($repo, $workdir, $file, $sha1, $symlinks) = @_;
+	my ($repo, $workdir, $file, $sha1) = @_;
 	my $null_sha1 = '0' x 40;
 
-	if ($sha1 ne $null_sha1 and not $symlinks) {
-		return 0;
-	}
-
 	if (! -e "$workdir/$file") {
 		# If the file doesn't exist in the working tree, we cannot
 		# use it.
@@ -213,8 +209,7 @@ sub setup_dir_diff
 
 		if ($rmode ne $null_mode) {
 			my ($use, $wt_sha1) = use_wt_file($repo, $workdir,
-							  $dst_path, $rsha1,
-							  $symlinks);
+							  $dst_path, $rsha1);
 			if ($use) {
 				push @working_tree, $dst_path;
 				$wtindex .= "$rmode $wt_sha1\t$dst_path\0";

t/t7800-difftool.sh

@@ -385,6 +385,25 @@ test_expect_success PERL,SYMLINKS 'difftool --dir-diff --symlink without unstage
 	test_cmp actual expect
 '
 
+write_script modify-right-file <<\EOF
+echo "new content" >"$2/file"
+EOF
+
+run_dir_diff_test 'difftool --dir-diff syncs worktree with unstaged change' '
+	test_when_finished git reset --hard &&
+	echo "orig content" >file &&
+	git difftool -d $symlinks --extcmd "$(pwd)/modify-right-file" branch &&
+	echo "new content" >expect &&
+	test_cmp expect file
+'
+
+run_dir_diff_test 'difftool --dir-diff syncs worktree without unstaged change' '
+	test_when_finished git reset --hard &&
+	git difftool -d $symlinks --extcmd "$(pwd)/modify-right-file" branch &&
+	echo "new content" >expect &&
+	test_cmp expect file
+'
+
 write_script modify-file <<\EOF
 echo "new content" >file
 EOF