git-svn: fix ls-tree usage with dash-prefixed paths

To find the blob object name given a tree and pathname, we were
incorrectly calling "git ls-tree" with a "--" argument followed
by the pathname of the file we wanted to get.

  git ls-tree <TREE> -- --dashed/path/name.c

Unlike many command-line interfaces, the "--" alone does not
symbolize the end of non-option arguments on the command-line.

ls-tree interprets the "--" as a prefix to match against, thus
the entire contents of the --dashed/* hierarchy would be
returned because the "--" matches "--dashed" and every path
under it.

Thanks to Anton Gyllenberg for pointing me toward the
Twisted repository as a real-world example of this case.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: Eric Wong

git-svn.perl

@@ -3384,15 +3384,18 @@ sub delete_entry {
 	return undef if ($gpath eq '');
 
 	# remove entire directories.
-	if (command('ls-tree', $self->{c}, '--', $gpath) =~ /^040000 tree/) {
+	my ($tree) = (command('ls-tree', '-z', $self->{c}, "./$gpath")
+	                 =~ /\A040000 tree ([a-f\d]{40})\t\Q$gpath\E\0/);
+	if ($tree) {
 		my ($ls, $ctx) = command_output_pipe(qw/ls-tree
 		                                     -r --name-only -z/,
-				                     $self->{c}, '--', $gpath);
+				                     $tree);
 		local $/ = "\0";
 		while (<$ls>) {
 			chomp;
-			$self->{gii}->remove($_);
-			print "\tD\t$_\n" unless $::_q;
+			my $rmpath = "$gpath/$_";
+			$self->{gii}->remove($rmpath);
+			print "\tD\t$rmpath\n" unless $::_q;
 		}
 		print "\tD\t$gpath/\n" unless $::_q;
 		command_close_pipe($ls, $ctx);
@@ -3411,8 +3414,8 @@ sub open_file {
 	goto out if is_path_ignored($path);
 
 	my $gpath = $self->git_path($path);
-	($mode, $blob) = (command('ls-tree', $self->{c}, '--', $gpath)
-	                     =~ /^(\d{6}) blob ([a-f\d]{40})\t/);
+	($mode, $blob) = (command('ls-tree', '-z', $self->{c}, "./$gpath")
+	                     =~ /\A(\d{6}) blob ([a-f\d]{40})\t\Q$gpath\E\0/);
 	unless (defined $mode && defined $blob) {
 		die "$path was not found in commit $self->{c} (r$rev)\n";
 	}