fix(bot): apply configuration changes without restarting the process

[TheMeinerLP]

The defect that started this: the bot started before any configuration existed, an administrator then ran /setup and /config set for every key, /config show reported "All required keys are set" — and the bot still did nothing. _configure_guild ran only from on_ready, so self._guilds stayed empty and on_voice_state_update found nothing to act on. It only worked after a manual pod restart.

The same held for every later change: pointing voice_channel_id at a different channel had no effect until someone restarted the process, while /config show kept insisting the value was set. That gap — between what the command reports and what the running process uses — is the actual bug.

What it does now

Configuration changes reconcile into the running bot. The hard part was never re-reading the config; it was doing so without losing a recording in progress. A change arriving mid-session is deferred and announced rather than forced, and /config set tells the administrator what actually took effect and what waits for the session to end.

Three defects review found afterwards, all reproduced

These were found by adversarial review of the first implementation, and each has a test that fails without its fix.

A failed upload could wedge a guild into recording nothing. SessionMachine moves to CLOSING before close() does its I/O, so a raise anywhere in encrypt/upload/enqueue left it parked there with nothing to call reset(). Both entry paths were affected. Recovery is now keyed on a needs_reset property — close()'s own precondition, asked rather than asserted — and runs in a finally. The error still propagates so the admin is not told a change took effect when the upload died, but it propagates out of a guild that can record again.

Same class, found adjacent and included: graceful_shutdown had one guild's failing upload cost every guild after it in the dict its still-open session. SIGTERM gives only one pass.

People already in the channel were never counted. A pipeline built or retargeted took its headcount only from subsequent voice-state updates. So an admin fixing the configuration while three people waited in the channel got nothing until somebody left and rejoined — the exact complaint this branch exists to fix, reappearing one layer down. One helper now turns current channel membership into a session, and every path calls it.

Reconfiguration raced with joins. _teardown awaits voice.leave() and pops _guilds only afterwards. A join inside that window found the pipeline, opened a session row against the channel being abandoned, and reconnected the voice client that had just been disconnected — leaving a row nothing would ever close and a connection nothing held. on_voice_state_update now takes the per-guild reconfigure lock and re-reads everything after acquiring it. Waiters are bounded to one per guild: the handler reads current membership rather than replaying a delta, so a later read is at least as fresh as anything a dropped update carried.

Verification

434 tests. Each of the six new ones was confirmed to fail against the unfixed client and for the right reason — checked by reverting only client.py.

Two fixtures carry most of the weight: ExplodingStore, whose put fails on demand, which is how you get a close to raise after the machine is in CLOSING; and BlockingVoiceReceiver, whose leave() suspends on demand, holding a reconcile open at exactly the window the race used.

The tests assert outcomes, not calls: that a second session opens and its job is enqueued after a failed upload; that people already present get a real recording with a packet landing and a job queued; that a join during teardown opens no row and reconnects nothing.

Residual

Carried knowingly rather than fixed, since neither is worse than today's behaviour: /config show still answers directly after its database round-trips and could exceed Discord's three-second deadline on a slow database, and a stored value that will not parse produces a NOTHING plan that reports the current config rather than the broken one.

[TheMeinerLP]

Rebased onto main after #34 landed. The two features collided in a way worth naming: #34 records the voice channel's name onto the session row, and this branch moves an idle service to a new channel in place via retarget(). Left as they were, a retarget would have carried the new channel id and the old channel name — the next protocol headed with a room the recording did not come from, which is worse than the None fallback to a bare link.

So retarget() now takes channel_name as a required argument rather than a defaulted one (a caller that forgets it should not compile past review), resolving it through a new SturnusClient._channel_name seam — the client is the only party holding a Discord connection; the worker that writes the header sees nothing but the id.

test_retarget_carries_the_channel_name_to_the_next_session covers it. Counter-checked: breaking only the assignment in retarget() fails that test and nothing else.