fix(Scripts/MagtheridonsLair): prevent Hellfire Channelers from respawning during boss fight

[TazzerMAN]

Changes Proposed:

This PR fixes a bug in Magtheridon's Lair where killing the 5 Hellfire Channelers in phase 1 caused them to respawn and rejoin the boss fight as soon as Magtheridon himself engaged the raid.

Root cause: SetBossState(DATA_MAGTHERIDON, IN_PROGRESS) was triggered late in the encounter (when Magtheridon engaged), at which point InstanceScript::UpdateMinionState() iterated over the registered minions (the Channelers) and called Respawn() on every dead one. The boss script never excluded that path.

Fix: transition the encounter to IN_PROGRESS as soon as the first Channeler enters combat. By the time Magtheridon's own JustEngagedWith runs, the state is already IN_PROGRESS and UpdateMinionState becomes a no-op for the dead Channelers.

Side benefit (intentional): room doors close and boss mods (DBM, etc.) are notified the moment a Channeler is engaged, rather than waiting for Magtheridon to attack a player. This matches the way the encounter behaves on retail.

Phase-1 wipe handling: since Magtheridon stays passive (immune to PC) until the last Channeler dies, his BossAI never triggers _EnterEvadeMode. The instance script now resets the encounter to NOT_STARTED when all Channelers have evaded; otherwise, after a phase-1 wipe, the room doors would stay locked. A new SmartAI hook on SMART_EVENT_EVADE for entry 17256 sends DATA_CHANNELER_COMBAT with data=0 to trigger the reset.

This PR proposes changes to:

• Scripts (bosses, spell scripts, creature scripts).
• Database (SAI, creatures, etc).

AI-assisted Pull Requests

• AI tools (e.g. ChatGPT, Claude, or similar) were used entirely or partially in preparing this pull request.

I used Claude (Anthropic) to help analyze the AzerothCore source, identify the root cause, and draft the patch. I tested all scenarios in-game on a current master build (which already includes #25379) and I understand the changes I'm submitting.

Issues Addressed:

Related to #25375 (closed on 2026-04-05 by #25379). #25379 fixed the scheduler-vs-UpdateVictim deadlock in boss_magtheridon.cpp so Magtheridon now becomes engageable properly, but it did not touch the Channeler-respawn flow described above — that flow is what this PR addresses.

No open issue currently tracks the respawn bug. I'm happy to open one if a maintainer prefers having a dedicated issue reference.

SOURCE:

• Live research (checked on live servers, e.g Classic WotLK, Retail, etc.)
• Knowledge databases or other public sources

On retail/Classic, killing the Hellfire Channelers permanently removes them for the duration of the encounter — they never respawn during phase 2/3. Confirmed via Wowhead, player guides and video evidence.

Tests Performed:

• Tested in-game by the author.
• Tested in-game by other community members.
• This pull request requires further testing and may have edge cases to be tested.

I tested on a current master build (commit 295e45b0a, which includes #25379).

How to Test the Changes:

• This pull request requires further testing.

Test scenarios

1. Normal kill — Enter Magtheridon's Lair, attack one of the Hellfire Channelers. Expect: doors close immediately, encounter is IN_PROGRESS. Kill all 5 Channelers; wait for Magtheridon to be released; defeat him. Expect: no Channeler ever respawns during phase 2/3.

2. Phase-1 wipe — Engage the Channelers, then wipe the raid. Expect: surviving Channelers evade and reset; once the last one is back home, the encounter resets to NOT_STARTED, doors open, and the raid can re-enter.

3. Phase-1 leave — Engage a Channeler, then have everyone leave the room (Feign Death / vanish / out of range). Expect: same as wipe — encounter resets when Channelers evade.

4. Phase 2/3 wipe — Kill all Channelers, engage Magtheridon, wipe. Expect: standard BossAI::_EnterEvadeMode reset; doors open. (Verifies the new code path doesn't interfere with the existing one.)

5. Victory — Defeat Magtheridon. Expect: doors open, encounter state DONE.

Known Issues and TODO List:

• None known. The fix is contained to the Magtheridon's Lair instance script and SmartAI for entry 17256.

[Nyeriah]

I'm not sure I'm seeing this one, the issue was that the boss resets/reenters combat switching from IN_COMBAT to NONE then IN_COMBAT again. Since the ads are registered as minions they would respawn when it changed to IN_COMBAT. I think the solution would rather be use formations to handle the respawn instead of the minion system and avoid the respawn measure in place

[TazzerMAN]

Thanks for the feedback, @Nyeriah :)

Formations make sense. In the case I ran into, it wasn’t really an oscillation, but rather the first transition to IN_PROGRESS when Mag engages after the 5th Channeler dies. That said, I think it still comes from the same root cause.
For v2 if you want, I’ll remove them from minionData[] and add a formation with RESPAWN_ON_EVADE.
Quick question: should the doors still close when a Channeler is pulled, or only once Mag engages?