Merge branch 'jc/send-email-reconfirm'

Validate interactive input to "git send-email" to avoid common
mistakes such as saying "y<RETURN>" to sender mail address whose
prompt is given with a correctly guessed default.

* jc/send-email-reconfirm:
  send-email: validate & reconfirm interactive responses

git-send-email.perl

@@ -681,6 +681,7 @@ sub ask {
 	my ($prompt, %arg) = @_;
 	my $valid_re = $arg{valid_re};
 	my $default = $arg{default};
+	my $confirm_only = $arg{confirm_only};
 	my $resp;
 	my $i = 0;
 	return defined $default ? $default : undef
@@ -698,6 +699,12 @@ sub ask {
 		if (!defined $valid_re or $resp =~ /$valid_re/) {
 			return $resp;
 		}
+		if ($confirm_only) {
+			my $yesno = $term->readline("Are you sure you want to use <$resp> [y/N]? ");
+			if (defined $yesno && $yesno =~ /y/i) {
+				return $resp;
+			}
+		}
 	}
 	return undef;
 }
@@ -745,13 +752,15 @@ sub file_declares_8bit_cte {
 if (!defined $sender) {
 	$sender = $repoauthor || $repocommitter || '';
 	$sender = ask("Who should the emails appear to be from? [$sender] ",
-	              default => $sender);
+	              default => $sender,
+		      valid_re => qr/\@.*\./, confirm_only => 1);
 	print "Emails will be sent from: ", $sender, "\n";
 	$prompting++;
 }
 
 if (!@initial_to && !defined $to_cmd) {
-	my $to = ask("Who should the emails be sent to? ");
+	my $to = ask("Who should the emails be sent to? ",
+		     valid_re => qr/\@.*\./, confirm_only => 1);
 	push @initial_to, parse_address_line($to) if defined $to; # sanitized/validated later
 	$prompting++;
 }
@@ -777,7 +786,8 @@ sub expand_one_alias {
 
 if ($thread && !defined $initial_reply_to && $prompting) {
 	$initial_reply_to = ask(
-		"Message-ID to be used as In-Reply-To for the first email? ");
+		"Message-ID to be used as In-Reply-To for the first email? ",
+		valid_re => qr/\@.*\./, confirm_only => 1);
 }
 if (defined $initial_reply_to) {
 	$initial_reply_to =~ s/^\s*<?//;