Interpreter: allow processing of empty result

This fixes .e.g.:

    <pragma-> !echo foo &{echo bar | { sed s/bar// }} baz

such that it produces the output "foo  baz" instead of no output at all.

lib/PBot/Core/Commands.pm

@@ -224,6 +224,7 @@ sub interpreter($self, $context) {
         );
 
         # return no output since it will be handled by process manager
+        $context->{'skip-handle-result'} = 1;
         return '';
     } else {
         # execute this command normally

lib/PBot/Core/Factoids/Code.pm

@@ -79,9 +79,9 @@ sub execute($self, $context) {
     # launch the `vm-client` applet
     $self->{pbot}->{applets}->execute_applet($context);
 
-    # return empty string since the applet process reader will
+    # return undef since the applet process reader will
     # pass the output along to the result handler
-    return '';
+    return undef;
 }
 
 1;

lib/PBot/Core/Factoids/Interpreter.pm

@@ -453,8 +453,7 @@ sub handle_action($self, $context, $action) {
         my ($lang, $code) = ($1, $2);
         $context->{lang} = $lang;
         $context->{code} = $code;
-        $self->{pbot}->{factoids}->{code}->execute($context);
+        return $self->{pbot}->{factoids}->{code}->execute($context);
-        return '';
     }
 
     return $action if $context->{special} eq 'code-factoid';

lib/PBot/Core/Interpreter.pm

@@ -230,7 +230,6 @@ sub process_line($self, $from, $nick, $user, $host, $text, $tags = '', $is_comma
 
     # interpret all parsed commands
     foreach $command (@commands) {
-
         # check if user is ignored
         # the `login` command gets a pass on the ignore filter
         if ($command !~ /^login / and $self->{pbot}->{ignorelist}->is_ignored($from, "$nick!$user\@$host")) {
@@ -578,9 +577,6 @@ sub interpret($self, $context) {
 # sends final command output to appropriate queues.
 # use context result if no result argument given.
 sub handle_result($self, $context, $result = $context->{result}) {
-    # ensure we have a command result to work with
-    return if not defined $result or not length $result;
-
     # preservation of consecutive whitespace is disabled by default
     $context->{preserve_whitespace} //= 0;
 
@@ -591,7 +587,13 @@ sub handle_result($self, $context, $result = $context->{result}) {
         $Data::Dumper::Indent = 2;
         $self->{pbot}->{logger}->log("Interpreter::handle_result [$result]\n");
         $self->{pbot}->{logger}->log(Dumper $context);
-        $Data::Dumper::Sortkeys = 1;
+    }
+
+    # ensure we have a command result to work with
+    if (!defined $result || $context->{'skip-handle-result'}) {
+        $self->{pbot}->{logger}->log("Skipping handle_result\n");
+        delete $context->{'skip-handle-result'};
+        return;
     }
 
     # strip and store /command prefixes

lib/PBot/Core/ProcessManager.pm

@@ -135,8 +135,8 @@ sub execute_process($self, $context, $subref, $timeout = undef, $reader_subref =
             $self->{pbot}->{select_handler}->add_reader($reader, sub { $self->process_pipe_reader($context->{pid}, @_) });
         }
 
-        # return empty string since reader will handle the output when child is finished
+        # return undef since reader will handle the output when child is finished
-        return '';
+        return undef;
     }
 }
 

lib/PBot/VERSION.pm

@@ -25,8 +25,8 @@ use PBot::Imports;
 # These are set by the /misc/update_version script
 use constant {
     BUILD_NAME     => "PBot",
-    BUILD_REVISION => 4820,
+    BUILD_REVISION => 4821,
-    BUILD_DATE     => "2024-10-31",
+    BUILD_DATE     => "2024-11-02",
 };
 
 sub initialize {}