add -p: avoid use of undefined $key when ReadKey -> EOF

b5cc003253 (add -i: ignore terminal escape sequences, 2011-05-17)
add an additional check to the original code to better handle keys
for escape sequences, but failed to account for the possibility
the first ReadKey call returned undef (ex: stdin closes) and that
was being handled fine by the original code in ca6ac7f135 (add -p:
prompt for single characters, 2009-02-05)

Add a test for undefined and encapsulate the loop and the original
print that relied on it within it.

After this, the following command (in a suitable repository state)
wouldn't print any error:

  $ git -c interactive.singleKey add -p </dev/null

Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/git-add--interactive.perl b/git-add--interactive.perl
index bc3a1e8effa321bd40bb83170646b98ca7f2e968..95887fd8e52ae9b4f0d7397f220376d1c994cbc5 100755 (executable)
--- a/git-add--interactive.perl
+++ b/git-add--interactive.perl
@@ -1175,15 +1175,17 @@ sub prompt_single_character {
                ReadMode 'cbreak';
                my $key = ReadKey 0;
                ReadMode 'restore';
-               if ($use_termcap and $key eq "\e") {
-                       while (!defined $term_escapes{$key}) {
-                               my $next = ReadKey 0.5;
-                               last if (!defined $next);
-                               $key .= $next;
+               if (defined $key) {
+                       if ($use_termcap and $key eq "\e") {
+                               while (!defined $term_escapes{$key}) {
+                                       my $next = ReadKey 0.5;
+                                       last if (!defined $next);
+                                       $key .= $next;
+                               }
+                               $key =~ s/\e/^[/;
                        }
-                       $key =~ s/\e/^[/;
+                       print "$key";
                }
-               print "$key" if defined $key;
                print "\n";
                return $key;
        } else {