Core/Movement: ported most movement updates from master branch and corrected behavior of CREATURE_STATIC_FLAG_4_PREVENT_SWIM

src/server/game/Entities/Unit/Unit.cpp

@@ -2940,10 +2940,23 @@ bool Unit::isInBackInMap(Unit const* target, float distance, float arc) const
 
 bool Unit::isInAccessiblePlaceFor(Creature const* c) const
 {
-    if (IsInWater())
-        return c->CanEnterWater();
-    else
-        return c->CanWalk() || c->CanFly();
+    // Aquatic creatures are not allowed to leave liquids
+    if (!IsInWater() && c->IsAquatic())
+        return false;
+
+    // Underwater special case. Some creatures may not go below liquid surfaces
+    if (IsUnderWater() && c->CannotPenetrateWater())
+        return false;
+
+    // Water checks
+    if (IsInWater() && !c->CanEnterWater())
+        return false;
+
+    // Some creatures are tied to the ocean floor and cannot chase swimming targets.
+    if (!IsOnOceanFloor() && c->IsUnderWater() && c->HasFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_CANT_SWIM))
+        return false;
+
+    return true;
 }
 
 bool Unit::IsInWater() const
@@ -2956,6 +2969,11 @@ bool Unit::IsUnderWater() const
     return GetLiquidStatus() & LIQUID_MAP_UNDER_WATER;
 }
 
+bool Unit::IsOnOceanFloor() const
+{
+    return GetLiquidStatus() & LIQUID_MAP_OCEAN_FLOOR;
+}
+
 void Unit::ProcessPositionDataChanged(PositionFullTerrainStatus const& data)
 {
     ZLiquidStatus oldLiquidStatus = GetLiquidStatus();
@@ -8673,6 +8691,10 @@ void Unit::UpdatePetCombatState()
 {
     ASSERT(!IsPet()); // player pets do not use UNIT_FLAG_PET_IN_COMBAT for this purpose - but player pets should also never have minions of their own to call this
 
+    // UNIT_FLAG_PET_IN_COMBAT is set by default when the summoner is in combat by himself
+    if (IsInCombat())
+        return;
+
     bool state = false;
     for (Unit* minion : m_Controlled)
         if (minion->IsInCombat())
@@ -11325,7 +11347,7 @@ void Unit::SetControlled(bool apply, UnitState state)
                 SetStunned(false);
                 break;
             case UNIT_STATE_ROOT:
-                if (HasAuraType(SPELL_AURA_MOD_ROOT) || GetVehicle() || (ToCreature() && ToCreature()->GetMovementTemplate().IsRooted()))
+                if (HasAuraType(SPELL_AURA_MOD_ROOT) || GetVehicle() || (IsCreature() && ToCreature()->IsSessile()))
                     return;
 
                 ClearUnitState(state);
@@ -12972,15 +12994,15 @@ bool Unit::IsFalling() const
 bool Unit::CanSwim() const
 {
     // Mirror client behavior, if this method returns false then client will not use swimming animation and for players will apply gravity as if there was no water
-    if (HasFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_CANNOT_SWIM))
+    if (HasFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_CANT_SWIM))
         return false;
     if (HasFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_PLAYER_CONTROLLED)) // is player
         return true;
-    if (HasFlag(UNIT_FIELD_FLAGS_2, 0x1000000))
+    if (HasFlag(UNIT_FIELD_FLAGS_2, UNIT_FLAG2_AI_WILL_ONLY_SWIM_IF_TARGET_SWIMS))
         return false;
     if (HasFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_PET_IN_COMBAT))
         return true;
-    return HasFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_RENAME | UNIT_FLAG_SWIMMING);
+    return HasFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_RENAME | UNIT_FLAG_CAN_SWIM);
 }
 
 void Unit::NearTeleportTo(Position const& pos, bool casting /*= false*/)