Core: Combat/threat system rewrite (PR #19930)

- PvE combat is now always mutual. UNIT_FLAG_IN_COMBAT is backed by actual references to the units we're in combat with.
- PvP combat is now also tracked, and almost always mutual; spells like Vanish and Feign Death can break this rule. That means we can easily determine a list of players we're fighting.
- By extension, IsInCombatWith now has sensible behavior when invoked on nonplayers.
- Threat and combat systems are no longer the same.
  - They still have an enforced relationship (threat implies combat - clearing combat clears threat)...
  - ...but we can have combat without threat. A creature (with threat list) isn't considered to be engaged until it has an entry on its threat list...
  - ...which means we can now faithfully replicate retail engage behavior. Combat on projectile launch - engagement start on projectile impact. Yay for progress!
- AI method refactor, as already ported in 6113b9d - `JustEngagedWith`, `JustEnteredCombat` and `JustExitedCombat`.
- Vehicle threat is now properly pooled on the main vehicle body (fixes #16542).
- Various edge case bug fixes for threat redirects (Misdirection "cancelling" Vigilance and similar).
- Target re-selection is now significantly faster.
- Fixed a ton of other smaller edge case bugs, probably.

Closes #7951 and #19998.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/server/game/Spells/SpellInfo.cpp b/src/server/game/Spells/SpellInfo.cpp
index f17b2481ea3..873bfbefdcf 100644
--- a/src/server/game/Spells/SpellInfo.cpp
+++ b/src/server/game/Spells/SpellInfo.cpp
@@ -1645,8 +1645,8 @@ SpellCastResult SpellInfo::CheckTarget(Unit const* caster, WorldObject const* ta
     // creature/player specific target checks
     if (unitTarget)
     {
-        // spells cannot be cast if player is in fake combat also
-        if (HasAttribute(SPELL_ATTR1_CANT_TARGET_IN_COMBAT) && (unitTarget->IsInCombat() || unitTarget->IsPetInCombat()))
+        // spells cannot be cast if target has a pet in combat either
+        if (HasAttribute(SPELL_ATTR1_CANT_TARGET_IN_COMBAT) && (unitTarget->IsInCombat() || unitTarget->HasFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_PET_IN_COMBAT)))
             return SPELL_FAILED_TARGET_AFFECTING_COMBAT;
 
         // only spells with SPELL_ATTR3_ONLY_TARGET_GHOSTS can target ghosts