fix(loot+firelands): stop cyclic loot-ref stack overflow & make heroic Ragnaros killable

LootMgr: LootTemplate::Process gains a thread_local recursion-depth guard (RAII, cap 50). A self-referencing reference_loot_template row (ref 104 -> 104) recursed until the worldserver stack overflowed and crashed on ICC boss/trash loot; this core does not reject such cycles at load. DB row already removed live; this hardens against any future cycle.

boss_ragnaros_firelands: heroic phase 4 had no completion path (every SetData(DONE)/EVENT_DIE lived in the !IsHeroic branch), leaving Ragnaros unkillable in heroic. Add a heroic death branch gated on new flag heroicPhaseFour (set after the phase-4 heal) so the encounter completes and grants credit/loot. Normal mode unchanged.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/server/game/Loot/LootMgr.cpp

@@ -585,6 +585,20 @@ void LootTemplate::CopyConditions(LootItem* li) const
 // Rolls for every item in the template and adds the rolled items the the loot
 void LootTemplate::Process(Loot& loot, bool rate, uint16 lootMode, uint8 groupId, Player const* player /*= nullptr*/, bool specOnly /*= false*/) const
 {
+    // Sylvania: guard against cyclic loot references (e.g. a reference_loot_template
+    // entry that references itself). Without this, such a cycle recurses until the
+    // worldserver stack overflows and crashes (observed on ICC loot, ref 104). The
+    // load-time loot verification of this core does not reject self/cyclic references,
+    // so we cap recursion defensively. No legitimate loot chain nests this deep.
+    static uint32 const MAX_LOOT_REFERENCE_DEPTH = 50;
+    static thread_local uint32 lootProcessDepth = 0;
+    struct DepthGuard { uint32& d; explicit DepthGuard(uint32& r) : d(r) { ++d; } ~DepthGuard() { --d; } } depthGuard(lootProcessDepth);
+    if (lootProcessDepth > MAX_LOOT_REFERENCE_DEPTH)
+    {
+        TC_LOG_ERROR("sql.sql", "LootTemplate::Process: loot reference recursion exceeded %u levels (likely a self-referencing or cyclic reference_loot_template entry) - aborting to prevent a stack-overflow crash", MAX_LOOT_REFERENCE_DEPTH);
+        return;
+    }
+
     if (groupId)                                            // Group reference uses own processing of the group
     {
         if (groupId > Groups.size())

src/server/scripts/Kalimdor/Firelands/boss_ragnaros_firelands.cpp

@@ -421,7 +421,7 @@ class boss_ragnaros_firelands: public CreatureScript
                 Creature* smash;
                 Creature* splitting;
                 uint8 sonOfFlameCount;
-                bool HeartCheck, introDone, intermission1, intermission1InProgress, intermission2, intermission2InProgress, phase3, inMeleeRange, heroicPhase, died;
+                bool HeartCheck, introDone, intermission1, intermission1InProgress, intermission2, intermission2InProgress, phase3, inMeleeRange, heroicPhase, heroicPhaseFour, died;
 
                 void Reset() override
                 {
@@ -454,6 +454,7 @@ class boss_ragnaros_firelands: public CreatureScript
                     phase3                  = false;
                     inMeleeRange            = false;
                     heroicPhase             = false;
+                    heroicPhaseFour         = false;
                     died                    = false;
                     sonOfFlameCount         = 0;
 
@@ -706,6 +707,42 @@ class boss_ragnaros_firelands: public CreatureScript
                         events.ScheduleEvent(EVENT_PHASE_FOUR, 1000);
                         heroicPhase = true;
                     }
+                    // Sylvania fix: heroic phase 4 ("True Power of the Firelord") previously
+                    // had NO completion path, leaving Ragnaros unkillable in heroic Firelands
+                    // (every SetData(DONE)/EVENT_DIE site lived only in the !IsHeroic() branch).
+                    // Mirror the normal-mode death once phase 4 is actually underway so the
+                    // encounter completes (me->Kill -> _JustDied -> SetBossState DONE) and
+                    // credit/achievement/loot are granted. Gated on heroicPhaseFour (set after
+                    // the phase-4 heal) so a sub-10% burst during the ~1s entry window cannot
+                    // short-circuit phase 4.
+                    else if (HealthBelowPct(10) && IsHeroic() && heroicPhaseFour && !died)
+                    {
+                        Talk(SAY_DEATH_H);
+
+                        me->AttackStop();
+                        me->CastStop();
+                        me->SetReactState(REACT_PASSIVE);
+                        me->SetFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_NON_ATTACKABLE | UNIT_FLAG_NOT_SELECTABLE);
+                        me->RemoveAllAuras();
+                        if (instance->GetData(DATA_TEAM) == ALLIANCE)
+                        {
+                            me->SummonGameObject(GO_CACHE_OF_THE_FIRELORD, 1016.043f, -57.436f, 55.333f, 3.151f, QuaternionData(), 30000);
+                        }
+                        else
+                        {
+                            me->SummonGameObject(GO_CACHE_OF_THE_FIRELORD_H, 1016.043f, -57.436f, 55.333f, 3.151f, QuaternionData(), 30000);
+                        }
+
+                        if (instance)
+                        {
+                            instance->SetData(DATA_RAGNAROS, DONE);
+                            instance->SendEncounterUnit(ENCOUNTER_FRAME_DISENGAGE, me); // Remove
+                        }
+
+                        events.ScheduleEvent(EVENT_DIE, 2000);
+                        me->HandleEmoteCommand(EMOTE_ONESHOT_SUBMERGE);
+                        died = true;
+                    }
 
                     events.Update(diff);
 
@@ -1032,6 +1069,7 @@ class boss_ragnaros_firelands: public CreatureScript
                                 Talk(SAY_PHASE_HEROIC_TEXT);
                                 me->RemoveAurasDueToSpell(SPELL_BASE_VISUAL);
                                 me->SetHealth(me->GetMaxHealth() / 2);
+                                heroicPhaseFour = true;                 // Sylvania: phase 4 is now active -> arm the heroic death check
                                 me->RemoveFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_REMOVE_CLIENT_CONTROL);
                                 me->SetObjectScale(1.2f);
                                 events.ScheduleEvent(EVENT_SUPERHEATED, 10000);