Don't add additional targets to allies that are already in combat

CHANGELOG.md

@@ -11,6 +11,7 @@
     Bug #3792: 1 frame late magicka recalc breaks early scripted magicka reactions to Intelligence change
     Bug #3846: Strings starting with "-" fail to compile if not enclosed in quotes
     Bug #3855: AI sometimes spams defensive spells
+    Bug #3867: All followers attack player when one follower enters combat with player
     Bug #3905: Great House Dagoth issues
     Bug #4203: Resurrecting an actor doesn't close the loot GUI
     Bug #4376: Moved actors don't respawn in their original cells
@@ -26,6 +27,7 @@
     Bug #5192: Actor turn rate is too slow
     Bug #5207: Loose summons can be present in scene
     Bug #5279: Ingame console stops auto-scrolling after clicking output
+    Bug #5318: Aiescort behaves differently from vanilla
     Bug #5371: 'Dead' slaughterfish added by mod are animated/alive
     Bug #5377: Console does not appear after using menutest in inventory
     Bug #5379: Wandering NPCs falling through cantons

apps/openmw/mwmechanics/actors.cpp

@@ -501,6 +501,9 @@ namespace MWMechanics
         // If an ally of actor1 has been attacked by actor2 or has attacked actor2, start combat between actor1 and actor2
         for (const MWWorld::Ptr& ally : allies1)
         {
+            // Don't let allies that are already in combat choose additional sides
+            if (ally.getClass().getCreatureStats(ally).getAiSequence().isInCombat())
+                continue;
             if (creatureStats1.getAiSequence().isInCombat(ally))
                 continue;
 

apps/openmw/mwmechanics/mechanicsmanagerimp.cpp

@@ -1457,7 +1457,14 @@ namespace MWMechanics
                 }
 
                 if (!peaceful)
+                {
                     startCombat(target, attacker);
+                    // Force friendly actors into combat to prevent infighting between followers
+                    std::set<MWWorld::Ptr> followersTarget;
+                    getActorsSidingWith(target, followersTarget);
+                    for(const auto& follower : followersTarget)
+                        startCombat(follower, attacker);
+                }
             }
         }