Mediabot v3 — Async eval, botNotice hardening, help filtering (May 2026)

Context

Audit of snapshot 20260503. Six modules touched. The main story is the completion of the async .eval pipe read, a missing truncation in botNotice, a repeated prepare() in the ban list loop, two stray warn calls, and three new Partyline commands.

Bug fixes

B1 — .eval parent read pipe was blocking the event loop

The child process was correctly forked with alarm() inside it for the timeout. But the parent was reading the pipe with a synchronous while (my $line = <$pipe>) loop. For the entire duration of the child — up to $eval_timeout seconds — the parent event loop was frozen: no IRC messages were processed, pings were not answered, and a long enough eval could cause a server disconnect.

The blocking read is replaced by an IO::Async::Stream attached to the pipe file handle. Lines are processed in the on_read callback as they arrive. An IO::Async::Timer::Countdown watchdog on the parent side kills the child (TERM then KILL) if it overruns the deadline. The event loop remains fully responsive throughout.

B2 — botNotice had no length truncation

botPrivmsg was already capped at 400 characters (IRC protocol limit). botNotice was not — a long notice would be silently truncated mid-line by the server, potentially at a bad UTF-8 boundary. The same substr($text, 0, 397) . '...' guard is now applied in botNotice before encoding.

B3 — _cmd_bans_list called prepare() inside the ban loop

for my $ban (@bans) {
    my $sth_now = $self->{dbh}->prepare('SELECT TIMESTAMPDIFF(...)');
    ...
}

One prepare() per ban row on every .bans / !bans call. The statement is now prepared once before the loop and reused with execute() on each iteration.

B4 — External::get_tmdb_info had a misplaced $self reference

The function get_tmdb_info is a standalone function, not a method — its signature is ($api_key, $lang, $query) with no $self. Replacing the warn with $self->{logger}->log(...) caused a compilation failure under use strict. Reverted to warn for this function.

B5 — Conf::get wrote to STDERR under MEDIABOT_DEBUG_CONF

The warn in Conf->get() for missing keys was routing to STDERR — invisible in the bot log. The call now checks for an attached logger object (set_logger()) and routes through it at DEBUG4. The warn fallback is kept for the early-init period before the logger exists.

Improvements

A1 — .eval async pipe (see B1)

Beyond fixing the blocking issue, the async implementation brings a cleaner separation of concerns: output lines are streamed to the Partyline session as they arrive rather than being buffered and sent all at once after the child exits. The watchdog timer is a proper IO::Async citizen and does not interfere with other scheduled tasks.

A2 — botNotice truncation (see B2)

Uniform treatment: both botPrivmsg and botNotice now cap at 400 characters before IRC encoding.

A3 — _cmd_bans_list prepare outside loop (see B3)

On a channel with 50 active bans, this reduces the number of DB round trips from 51 (1 list query + 50 TIMESTAMPDIFF prepares) to 2 (1 list query + 1 TIMESTAMPDIFF prepare reused 50 times).

A4 — !help filtered by user level

mbHelp_ctx previously sent a single wiki link. It now sends a list of commands filtered by the caller’s level:

[public]  help, uptime, status, version, date, leet, echo, colors,
          whoami, seen, q, addquote, weather, resolve, ban, kickban,
          unban, bans
[master+] join, part, nick, mode, kick, topic, say, timers, log
[owner]   die, restart, jump, rehash, addtimer, remtimer, eval

The wiki link is still appended for full documentation.

A6 — .uptime from the Partyline

.uptime
Uptime: 2d 4h 17m 32s

Shows the bot uptime formatted in days, hours, minutes and seconds. Reads $bot->{metrics}->{started} set at bot startup.

A7 — .schedule start/stop <name> from the Partyline

.schedule stop channel_log_purge
Task 'channel_log_purge' stopped.

.schedule start channel_log_purge
Task 'channel_log_purge' started.

Allows starting and stopping individual Scheduler tasks at runtime without restarting the bot. Lists available task names if called without arguments. Owner level required via Partyline authentication.

Files changed