fix: guard claim-link entries against stale indices and dead groups

ClaimLink/ClaimLinkChatCommand.cs

@@ -326,9 +326,12 @@ public static class ClaimLinkChatCommand
             $"{claimDesc} will be linked into '{groupName}'.",
             () =>
             {
-                ClaimLinkModSystem.Registry.AddEntry(playerUid, groupId, claimIndex);
+                bool success = ClaimLinkModSystem.Registry.AddEntry(playerUid, groupId, claimIndex);
-
+                return success
-                return TextCommandResult.Success($"Linked {claimDesc} to '{groupName}'.");
+                    ? TextCommandResult.Success($"Linked {claimDesc} to '{groupName}'.")
+                    : TextCommandResult.Error(
+                        $"Unable to link {claimIndex} to '{groupName}' it is currently being modified."
+                    );
             }
         );
     }
@@ -546,7 +549,9 @@ public static class ClaimLinkChatCommand
     public static TextCommandResult List(TextCommandCallingArgs args)
     {
         List<int> groupIds = ClaimLinkModSystem
-            .Registry.All.OrderByDescending(id => ClaimLinkModSystem.Registry.MemberCountForGroup(id))
+            .Registry.All.OrderByDescending(id =>
+                ClaimLinkModSystem.Registry.MemberCountForGroup(id)
+            )
             .ToList();
 
         if (groupIds.Count == 0)

ClaimLink/ClaimLinkModSystem.cs

@@ -19,10 +19,10 @@ public class ClaimLinkModSystem : ModSystem
     public override void StartServerSide(ICoreServerAPI api)
     {
         LandClaimAPI = api.World.Claims;
+        World = api.World;
+        Groups = api.Groups;
         Logger = api.Logger;
         Registry = new ClaimLinkRegistry(api.WorldManager.SaveGame);
-        Groups = api.Groups;
-        World = api.World;
 
         CmdListener = new ClaimLinkCommandListener();
         CommandHookModSystem.Register(CmdListener);

ClaimLink/ClaimLinkRegistry.cs

@@ -63,14 +63,19 @@ public class ClaimLinkRegistry
         return null;
     }
 
-    public void AddEntry(string uid, int groupId, int claimIndex)
+    public bool AddEntry(string uid, int groupId, int claimIndex)
     {
+        if (ClaimLinkCommandListener.PendingLoads.ContainsKey(uid))
+            return false;
+        if (!Exists(groupId))
+            return false;
         if (!entries.TryGetValue(uid, out var groups))
             entries[uid] = groups = new();
         if (!groups.TryGetValue(groupId, out var claims))
             groups[groupId] = claims = new();
         claims.Add(claimIndex);
         Save();
+        return true;
     }
 
     public void RemoveEntry(string uid, int groupId, int claimIndex)
@@ -93,6 +98,7 @@ public class ClaimLinkRegistry
                 if (claims[i] > removedIndex)
                     claims[i]--;
         }
+
         Prune();
         Save();
     }
@@ -119,6 +125,7 @@ public class ClaimLinkRegistry
             if (i >= 0)
                 claims[i] = newIndex;
         }
+
         Save();
     }
 

ClaimLink/LandCommandListener.cs

@@ -83,6 +83,7 @@ public class ClaimLinkCommandListener : ICommandHookListener
 
         ClaimLinkModSystem.Registry.ClaimSaved(uid, pendingIndex);
         PendingLoads.Remove(uid);
+        ClaimLinkChatCommand.PendingActions.Remove(uid);
     }
 
     private static void ClaimLoad(Caller caller, CmdArgs args)
@@ -119,6 +120,7 @@ public class ClaimLinkCommandListener : ICommandHookListener
             return;
 
         ClaimLinkModSystem.Registry.ClaimRemoved(uid, (int)claimIndex);
+        ClaimLinkChatCommand.PendingActions.Remove(uid);
     }
 
     private static void AdminFree(Caller caller, CmdArgs args)
@@ -132,7 +134,10 @@ public class ClaimLinkCommandListener : ICommandHookListener
 
         foreach (LandClaim c in claims)
             if (ClaimLinkModSystem.TryResolveClaimIndex(c.OwnedByPlayerUid, c, out int claimIndex))
+            {
                 ClaimLinkModSystem.Registry.ClaimRemoved(c.OwnedByPlayerUid, claimIndex);
+                ClaimLinkChatCommand.PendingActions.Remove(c.OwnedByPlayerUid);
+            }
     }
 
     internal static void OnPlayerDisconnect(IServerPlayer player)