Fix ghosts getting spawned in nullspace (#27617)

* Add tests for ghost spawn position

* Make ghosts spawn immediately

* Format mind system

* Move ghost spawning to GhostSystem

* Spawn ghost on grid or map

This fixes the ghosts being attached the parent entity instead of the grid.

* Move logging out of the ghost system

* Make round start observer spawn using GhostSystem

* Move GameTicker ghost spawning to GhostSystem

Moved the more robust character name selection code over.
Moved the TimeOfDeath code over.
Added canReturn logic.

* Add overrides and default for ghost spawn coordinates

* Add warning log to ghost spawn fail

* Clean up test

* Dont spawn ghost on map delete

* Minor changes to the role test

* Fix role test failing to spawn ghost

It was failing the map check due to using Nullspace

* Fix ghost tests when running in parallel

Not sure what happened, but it seems to be because they were running simultaneously and overwriting values.

* Clean up ghost tests

* Test that map deletion does not spawn ghosts

* Spawn ghost on the next available map

* Disallow spawning on deleted maps

* Fix map deletion ghost test

* Cleanup

Content.Server/Ghost/GhostSystem.cs

@@ -19,6 +19,7 @@ using Content.Shared.Movement.Systems;
 using Content.Shared.Storage.Components;
 using Robust.Server.GameObjects;
 using Robust.Server.Player;
+using Robust.Shared.Map;
 using Robust.Shared.Physics.Components;
 using Robust.Shared.Physics.Systems;
 using Robust.Shared.Player;
@@ -42,6 +43,8 @@ namespace Content.Server.Ghost
         [Dependency] private readonly GameTicker _ticker = default!;
         [Dependency] private readonly TransformSystem _transformSystem = default!;
         [Dependency] private readonly VisibilitySystem _visibilitySystem = default!;
+        [Dependency] private readonly MetaDataSystem _metaData = default!;
+        [Dependency] private readonly IMapManager _mapManager = default!;
 
         private EntityQuery<GhostComponent> _ghostQuery;
         private EntityQuery<PhysicsComponent> _physicsQuery;
@@ -389,5 +392,59 @@ namespace Content.Server.Ghost
 
             return ghostBoo.Handled;
         }
+
+        public EntityUid? SpawnGhost(Entity<MindComponent?> mind, EntityUid targetEntity,
+            bool canReturn = false)
+        {
+            _transformSystem.TryGetMapOrGridCoordinates(targetEntity, out var spawnPosition);
+            return SpawnGhost(mind, spawnPosition, canReturn);
+        }
+
+        public EntityUid? SpawnGhost(Entity<MindComponent?> mind, EntityCoordinates? spawnPosition = null,
+            bool canReturn = false)
+        {
+            if (!Resolve(mind, ref mind.Comp))
+                return null;
+
+            // Test if the map is being deleted
+            var mapUid = spawnPosition?.GetMapUid(EntityManager);
+            if (mapUid == null || TerminatingOrDeleted(mapUid.Value))
+                spawnPosition = null;
+
+            spawnPosition ??= _ticker.GetObserverSpawnPoint();
+
+            if (!spawnPosition.Value.IsValid(EntityManager))
+            {
+                Log.Warning($"No spawn valid ghost spawn position found for {mind.Comp.CharacterName}"
+                    + " \"{ToPrettyString(mind)}\"");
+                _minds.TransferTo(mind.Owner, null, createGhost: false, mind: mind.Comp);
+                return null;
+            }
+
+            var ghost = SpawnAtPosition(GameTicker.ObserverPrototypeName, spawnPosition.Value);
+            var ghostComponent = Comp<GhostComponent>(ghost);
+
+            // Try setting the ghost entity name to either the character name or the player name.
+            // If all else fails, it'll default to the default entity prototype name, "observer".
+            // However, that should rarely happen.
+            if (!string.IsNullOrWhiteSpace(mind.Comp.CharacterName))
+                _metaData.SetEntityName(ghost, mind.Comp.CharacterName);
+            else if (!string.IsNullOrWhiteSpace(mind.Comp.Session?.Name))
+                _metaData.SetEntityName(ghost, mind.Comp.Session.Name);
+
+            if (mind.Comp.TimeOfDeath.HasValue)
+            {
+                SetTimeOfDeath(ghost, mind.Comp.TimeOfDeath!.Value, ghostComponent);
+            }
+
+            SetCanReturnToBody(ghostComponent, canReturn);
+
+            if (canReturn)
+                _minds.Visit(mind.Owner, ghost, mind.Comp);
+            else
+                _minds.TransferTo(mind.Owner, ghost, mind: mind.Comp);
+            Log.Debug($"Spawned ghost \"{ToPrettyString(ghost)}\" for {mind.Comp.CharacterName}.");
+            return ghost;
+        }
     }
 }