Merge branch 'jk/difftool-dir-diff-edit-fix'

"git difftool --dir-diff" made symlinks to working tree files when
preparing a temporary directory structure, so that accidental edits
of these files in the difftool are reflected back to the working
tree, but the logic to decide when to do so was not quite right.

* jk/difftool-dir-diff-edit-fix:
  difftool --dir-diff: symlink all files matching the working tree
  difftool: avoid double slashes in symlink targets
  git-difftool(1): fix formatting of --symlink description

1 files changed, 21 insertions, 4 deletions

diff --git a/git-difftool.perl b/git-difftool.perl
index 12231fbc67..663640d33c 100755
--- a/git-difftool.perl
+++ b/git-difftool.perl
@@ -83,6 +83,21 @@ sub exit_cleanup
 	exit($status | ($status >> 8));
 }
 
+sub use_wt_file
+{
+	my ($repo, $workdir, $file, $sha1, $symlinks) = @_;
+	my $null_sha1 = '0' x 40;
+
+	if ($sha1 eq $null_sha1) {
+		return 1;
+	} elsif (not $symlinks) {
+		return 0;
+	}
+
+	my $wt_sha1 = $repo->command_oneline('hash-object', "$workdir/$file");
+	return $sha1 eq $wt_sha1;
+}
+
 sub setup_dir_diff
 {
 	my ($repo, $workdir, $symlinks) = @_;
@@ -159,10 +174,10 @@ EOF
 		}
 
 		if ($rmode ne $null_mode) {
-			if ($rsha1 ne $null_sha1) {
-				$rindex .= "$rmode $rsha1\t$dst_path\0";
-			} else {
+			if (use_wt_file($repo, $workdir, $dst_path, $rsha1, $symlinks)) {
 				push(@working_tree, $dst_path);
+			} else {
+				$rindex .= "$rmode $rsha1\t$dst_path\0";
 			}
 		}
 	}
@@ -209,7 +224,9 @@ EOF
 	delete($ENV{GIT_INDEX_FILE});
 
 	# Changes in the working tree need special treatment since they are
-	# not part of the index
+	# not part of the index. Remove any trailing slash from $workdir
+	# before starting to avoid double slashes in symlink targets.
+	$workdir =~ s|/$||;
 	for my $file (@working_tree) {
 		my $dir = dirname($file);
 		unless (-d "$rdir/$dir") {