Overview

This session focused on a methodical bottom-up audit of all 32 Perl modules in the stack. No new features — just making the existing code more correct, more defensive, and less likely to silently misbehave under load or after a connection drop.

Three distinct categories of issues were addressed: resource leaks from unclosed database statement handles, incomplete reconnection logic in the IRC event handlers, and redundant use declarations scattered across modules.

1. The Statement Handle Audit

Every call to $dbh->prepare() should have a matching $sth->finish() when the handle is no longer needed. Without it, the underlying database cursor stays open, consuming server-side resources. With MariaDB’s default settings this is mostly harmless in low-traffic bots, but it’s technically a resource leak and can cause subtle issues with connection pooling or under mariadb_auto_reconnect.

The audit found 11 unclosed handles across 4 modules.

Helpers.pm

_tz_exists() was the most compact offender. The entire function was:

my $sth = $self->{dbh}->prepare("SELECT tz FROM TIMEZONE WHERE tz LIKE ?");
return $sth->execute($tz) && $sth->fetchrow_hashref();

This returns immediately after the fetch, leaving the handle open. Fixed by capturing the result explicitly and calling finish before returning:

unless ($sth->execute($tz)) { $sth->finish; return undef; }
my $ref = $sth->fetchrow_hashref();
$sth->finish;
return $ref;

mp3_ctx() had 5 prepares and 4 finishes. The missing one was in the error branch of the $sql_first query — a return statement inside the unless block that escaped before finish could be called. Added $sth->finish if $sth inside the error branch.

Stray use Encode — a use Encode qw(encode) declaration was found at line 857, sitting between two subs, outside any package block, duplicating the one already present at line 452. Removed.

UserCommands.pm — mbModUser_ctx()

This function handles the !moduser command with multiple subcommands. The AUTOLOGIN and FORTNITEID sections both followed the same pattern:

$sth = $self->{dbh}->prepare("SELECT * FROM USER WHERE ...");
$sth->execute($target_nick);

if ($sth->fetchrow_hashref()) {
    # ...
} else {
    $sth = $self->{dbh}->prepare("UPDATE USER SET ...");
    # ...
}

The problem: $sth is overwritten by the UPDATE prepare without finishing the SELECT handle first. Fixed by capturing the fetchrow result into a named variable and calling finish immediately before the potential overwrite:

$sth->execute($target_nick);
my $already_on = $sth->fetchrow_hashref();
$sth->finish;

if ($already_on) { ... }
else {
    $sth = $self->{dbh}->prepare("UPDATE ...");
    ...
}

This pattern was applied to both AUTOLOGIN branches (on/off) and the FORTNITEID section.

ChannelCommands.pm

get_channel_by_name() used an early return undef that bypassed finish. Refactored to fetch the row, finish the handle, then return.

getChannelOwner() fetched a row and returned it directly inside the if block without finishing. Refactored to fetch into a variable, finish, then return conditionally.

purgeChannel_ctx() had three DELETE statements whose error branches contained return without calling finish. Added $sth->finish if $sth inside each error branch and after the successful path.

Hailo.pm — set_hailo_channel_ratio()

The initial SELECT to check whether a HAILO_CHANNEL row exists was overwritten by either an UPDATE or an INSERT prepare depending on which branch was taken. Fixed the same way as mbModUser_ctx: capture result, finish, then branch.

2. Reconnection Logic Completed

Mediabot reconnects to IRC when it detects a dropped connection. Before this session, reconnection was triggered by:

• on_timer_tick — detects !$irc->is_connected on each 5-second tick
• on_message_KILL — server-sent KILL command

Two handlers were missing reconnection logic:

on_message_ERROR — when the IRC server sends an ERROR message (typically before closing the connection), the handler only logged the message. It now follows the same pattern as on_message_KILL:

unless ($mediabot->getQuit()) {
    $mediabot->setServer(undef);
    $loop->stop;
    my $delay = int($mediabot->{conf}->get('main.RECONNECT_DELAY') // 30);
    sleep $delay;
    reconnect();
}

All three reconnection paths now share the same RECONNECT_DELAY configuration key (added to mediabot.sample.conf in the previous session, default 30 seconds).

3. Duplicate use Declarations

Four modules had redundant use statements — the same module imported twice with identical arguments. These were cleaned up:

Important caveat caught during this work: External.pm legitimately has two different use HTML::Entities lines that are not duplicates:

use HTML::Entities qw(decode_entities);   # imports the function
use HTML::Entities '%entity2char';        # imports the hash

Removing both and keeping only one caused a compilation error (Global symbol "%entity2char" requires explicit package name). The rule is: if the import lists are different, the lines are not duplicates.

Files Changed

Helpers.pm, UserCommands.pm, ChannelCommands.pm, Hailo.pm, mediabot.pl, DBCommands.pm, External.pm, Mediabot.pm

“It is our choices that show what we truly are, far more than our resource handles.” — Albus Dumbledore, probably, if he’d written Perl