Fix bug where long commands crash i3

Commands with more than 10 words would result in i3 crashing. The root
cause is that the stack which holds arguments with identifiers is
only 10 big, but generate-command-parser.pl was giving every word an
identifier of "".

generate-command-parser.pl

@@ -228,8 +228,15 @@ sub slurp {
             ($call_identifier) = ($next_state =~ /^call ([0-9]+)$/);
             $next_state = '__CALL';
         }
-        my $identifier = $token->{identifier};
-        say $tokfh qq|    { "$token_name", "$identifier", $next_state, { $call_identifier } },|;
+        my $identifier;
+        # Set $identifier to NULL if there is no identifier
+        if ($token->{identifier} eq ""){
+            $identifier = "NULL"
+        }
+        else{
+            $identifier = qq|"$token->{identifier}"|;
+        }
+        say $tokfh qq|    { "$token_name", $identifier, $next_state, { $call_identifier } },|;
     }
     say $tokfh '};';
 }

testcases/t/315-long-commands.t

@@ -0,0 +1,46 @@
+#!perl
+# vim:ts=4:sw=4:expandtab
+#
+# Please read the following documents before working on tests:
+# • https://build.i3wm.org/docs/testsuite.html
+#   (or docs/testsuite)
+#
+# • https://build.i3wm.org/docs/lib-i3test.html
+#   (alternatively: perldoc ./testcases/lib/i3test.pm)
+#
+# • https://build.i3wm.org/docs/ipc.html
+#   (or docs/ipc)
+#
+# • http://onyxneon.com/books/modern_perl/modern_perl_a4.pdf
+#   (unless you are already familiar with Perl)
+#
+# Test that commands with more than 10 non-identified words doesn't works
+# 10 is the magic number chosen for the stack size which is why it's used here
+# Ticket: #2968
+# Bug still in: 4.19.2-103-gfc65ca36
+use i3test;
+
+######################################################################
+# 1) run a long command
+######################################################################
+
+my $i3 = i3(get_socket_path());
+my $tmp = fresh_workspace;
+
+my $floatwin = open_floating_window;
+
+
+my ($absolute_before, $top_before) = $floatwin->rect;
+
+cmd 'move window container to window container to window container to left';
+
+sync_with_i3;
+
+my ($absolute, $top) = $floatwin->rect;
+
+is($absolute->x, ($absolute_before->x - 10), 'moved 10 px to the left');
+is($absolute->y, $absolute_before->y, 'y not changed');
+is($absolute->width, $absolute_before->width, 'width not changed');
+is($absolute->height, $absolute_before->height, 'height not changed');
+
+done_testing;