send-email: allow send-email to run outside a repo

send-email is supposed to be able to run from outside a repo. This
ability was broken by commits caf0c3d (make the message file name more
specific) and 5df9fcf (interpret unknown files as revision lists).

This commit provides a fix for both.

Signed-off-by: Jay Soffian <jaysoffian@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-send-email.perl

@@ -23,7 +23,7 @@
 use Text::ParseWords;
 use Data::Dumper;
 use Term::ANSIColor;
-use File::Temp qw/ tempdir /;
+use File::Temp qw/ tempdir tempfile /;
 use Error qw(:try);
 use Git;
 
@@ -156,7 +156,10 @@ sub format_2822_time {
 # Behavior modification variables
 my ($quiet, $dry_run) = (0, 0);
 my $format_patch;
-my $compose_filename = $repo->repo_path() . "/.gitsendemail.msg.$$";
+my $compose_filename = ($repo ?
+	tempfile(".gitsendemail.msg.XXXXXX", DIR => $repo->repo_path()) :
+	tempfile(".gitsendemail.msg.XXXXXX", DIR => "."))[1];
+
 
 # Handle interactive edition of files.
 my $multiedit;
@@ -267,6 +270,9 @@ sub signal_handler {
     usage();
 }
 
+die "Cannot run git format-patch from outside a repository\n"
+	if $format_patch and not $repo;
+
 # Now, let's fill any that aren't set in with defaults:
 
 sub read_config {
@@ -404,6 +410,7 @@ sub split_addrs {
 
 # returns 1 if the conflict must be solved using it as a format-patch argument
 sub check_file_rev_conflict($) {
+	return unless $repo;
 	my $f = shift;
 	try {
 		$repo->command('rev-parse', '--verify', '--quiet', $f);
@@ -445,6 +452,8 @@ ($)
 }
 
 if (@rev_list_opts) {
+	die "Cannot run git format-patch from outside a repository\n"
+		unless $repo;
 	push @files, $repo->command('format-patch', '-o', tempdir(CLEANUP => 1), @rev_list_opts);
 }