From aac17c33210b15d144551cb677ed0bee94b55afd Mon Sep 17 00:00:00 2001
From: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>
Date: Sun, 15 Oct 2023 05:02:36 +1100
Subject: [PATCH] Cleanup more follower leaks (#20902)

* Cleanup more follower leaks

Rather than check stop everywhere we'll just check it on start and cleanup the old following. If someone were already following and followed something new the FollowedComponent would never get cleaned up and would never have its ref to the entity removed.

* Don't cause archetype changes
---
 Content.Shared/Follower/FollowerSystem.cs | 27 ++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/Content.Shared/Follower/FollowerSystem.cs b/Content.Shared/Follower/FollowerSystem.cs
index 38c0e5ada3..e4a0488dfb 100644
--- a/Content.Shared/Follower/FollowerSystem.cs
+++ b/Content.Shared/Follower/FollowerSystem.cs
@@ -138,7 +138,20 @@ public sealed class FollowerSystem : EntitySystem
             targetXform = Transform(targetXform.ParentUid);
         }
 
-        var followerComp = EnsureComp<FollowerComponent>(follower);
+        // Cleanup old following.
+        if (TryComp<FollowerComponent>(follower, out var followerComp))
+        {
+            // Already following you goob
+            if (followerComp.Following == entity)
+                return;
+
+            StopFollowingEntity(follower, followerComp.Following, deparent: false, removeComp: false);
+        }
+        else
+        {
+            followerComp = AddComp<FollowerComponent>(follower);
+        }
+        
         followerComp.Following = entity;
 
         var followedComp = EnsureComp<FollowedComponent>(entity);
@@ -167,14 +180,14 @@ public sealed class FollowerSystem : EntitySystem
 
         RaiseLocalEvent(follower, followerEv);
         RaiseLocalEvent(entity, entityEv);
-        Dirty(followedComp);
+        Dirty(entity, followedComp);
     }
 
     /// <summary>
     ///     Forces an entity to stop following another entity, if it is doing so.
     /// </summary>
     /// <param name="deparent">Should the entity deparent itself</param>
-    public void StopFollowingEntity(EntityUid uid, EntityUid target, FollowedComponent? followed = null, bool deparent = true)
+    public void StopFollowingEntity(EntityUid uid, EntityUid target, FollowedComponent? followed = null, bool deparent = true, bool removeComp = true)
     {
         if (!Resolve(target, ref followed, false))
             return;
@@ -186,8 +199,12 @@ public sealed class FollowerSystem : EntitySystem
         if (followed.Following.Count == 0)
             RemComp<FollowedComponent>(target);
 
-        RemComp<FollowerComponent>(uid);
-        RemComp<OrbitVisualsComponent>(uid);
+        if (removeComp)
+        {
+            RemComp<FollowerComponent>(uid);
+            RemComp<OrbitVisualsComponent>(uid);
+        }
+
         var uidEv = new StoppedFollowingEntityEvent(target, uid);
         var targetEv = new EntityStoppedFollowingEvent(target, uid);