Nullable grid Uid (#8798)

Content.Client/AI/ClientPathfindingDebugSystem.cs

@@ -294,7 +294,7 @@ namespace Content.Client.AI
         private void DrawCachedRegions(DrawingHandleScreen screenHandle, Box2 viewport)
         {
             var transform = _entities.GetComponentOrNull<TransformComponent>(_playerManager.LocalPlayer?.ControlledEntity);
-            if (transform == null || !CachedRegions.TryGetValue(transform.GridEntityId, out var entityRegions))
+            if (transform == null || transform.GridUid == null || !CachedRegions.TryGetValue(transform.GridUid.Value, out var entityRegions))
             {
                 return;
             }
@@ -312,7 +312,7 @@ namespace Content.Client.AI
                         screenTile.X + 15.0f,
                         screenTile.Y + 15.0f);
 
-                    screenHandle.DrawRect(box, _cachedRegionColors[transform.GridEntityId][region]);
+                    screenHandle.DrawRect(box, _cachedRegionColors[transform.GridUid.Value][region]);
                 }
             }
         }
@@ -344,7 +344,8 @@ namespace Content.Client.AI
         {
             var attachedEntity = _playerManager.LocalPlayer?.ControlledEntity;
             if (!_entities.TryGetComponent(attachedEntity, out TransformComponent? transform) ||
-                !Regions.TryGetValue(transform.GridEntityId, out var entityRegions))
+                transform.GridUid == null ||
+                !Regions.TryGetValue(transform.GridUid.Value, out var entityRegions))
             {
                 return;
             }
@@ -364,7 +365,7 @@ namespace Content.Client.AI
                             screenTile.X + 15.0f,
                             screenTile.Y + 15.0f);
 
-                        screenHandle.DrawRect(box, _regionColors[_entities.GetComponent<TransformComponent>(attachedEntity.Value).GridEntityId][chunk][region]);
+                        screenHandle.DrawRect(box, _regionColors[transform.GridUid.Value][chunk][region]);
                     }
                 }
             }

Content.Client/Administration/UI/Tabs/AtmosTab/AddAtmosWindow.xaml.cs

@@ -24,7 +24,7 @@ namespace Content.Client.Administration.UI.Tabs.AtmosTab
             foreach (var grid in _data)
             {
                 var player = IoCManager.Resolve<IPlayerManager>().LocalPlayer?.ControlledEntity;
-                var playerGrid = IoCManager.Resolve<IEntityManager>().GetComponentOrNull<TransformComponent>(player)?.GridEntityId;
+                var playerGrid = IoCManager.Resolve<IEntityManager>().GetComponentOrNull<TransformComponent>(player)?.GridUid;
                 GridOptions.AddItem($"{grid.GridEntityId} {(playerGrid == grid.GridEntityId ? " (Current)" : "")}");
             }
 

Content.Client/Administration/UI/Tabs/AtmosTab/AddGasWindow.xaml.cs

@@ -28,7 +28,7 @@ namespace Content.Client.Administration.UI.Tabs.AtmosTab
             foreach (var grid in _gridData)
             {
                 var player = IoCManager.Resolve<IPlayerManager>().LocalPlayer?.ControlledEntity;
-                var playerGrid = IoCManager.Resolve<IEntityManager>().GetComponentOrNull<TransformComponent>(player)?.GridEntityId;
+                var playerGrid = IoCManager.Resolve<IEntityManager>().GetComponentOrNull<TransformComponent>(player)?.GridUid;
                 GridOptions.AddItem($"{grid.GridEntityId} {(playerGrid == grid.GridEntityId ? " (Current)" : "")}");
             }
 

Content.Client/Administration/UI/Tabs/AtmosTab/FillGasWindow.xaml.cs

@@ -28,7 +28,7 @@ namespace Content.Client.Administration.UI.Tabs.AtmosTab
             foreach (var grid in _gridData)
             {
                 var player = IoCManager.Resolve<IPlayerManager>().LocalPlayer?.ControlledEntity;
-                var playerGrid = IoCManager.Resolve<IEntityManager>().GetComponentOrNull<TransformComponent>(player)?.GridEntityId;
+                var playerGrid = IoCManager.Resolve<IEntityManager>().GetComponentOrNull<TransformComponent>(player)?.GridUid;
                 GridOptions.AddItem($"{grid.GridEntityId} {(playerGrid == grid.GridEntityId ? " (Current)" : "")}");
             }
 

Content.Client/Administration/UI/Tabs/AtmosTab/SetTemperatureWindow.xaml.cs

@@ -24,7 +24,7 @@ namespace Content.Client.Administration.UI.Tabs.AtmosTab
             foreach (var grid in _data)
             {
                 var player = IoCManager.Resolve<IPlayerManager>().LocalPlayer?.ControlledEntity;
-                var playerGrid = IoCManager.Resolve<IEntityManager>().GetComponentOrNull<TransformComponent>(player)?.GridEntityId;
+                var playerGrid = IoCManager.Resolve<IEntityManager>().GetComponentOrNull<TransformComponent>(player)?.GridUid;
                 GridOptions.AddItem($"{grid.GridEntityId} {(playerGrid == grid.GridEntityId ? " (Current)" : "")}");
             }
 

Content.Client/Audio/BackgroundAudioSystem.cs

@@ -89,7 +89,7 @@ namespace Content.Client.Audio
         {
             if(_playMan.LocalPlayer is null || _playMan.LocalPlayer.ControlledEntity != message.Entity) return;
             if (!TryComp<TransformComponent>(message.Entity, out var xform) ||
-                !_mapManager.TryGetGrid(xform.GridEntityId, out var grid)) return;
+                !_mapManager.TryGetGrid(xform.GridUid, out var grid)) return;
 
             var tileDef = (ContentTileDefinition) _tileDefMan[grid.GetTileRef(xform.Coordinates).Tile.TypeId];
 

Content.Client/Eye/EyeLerpingSystem.cs

@@ -105,7 +105,7 @@ public sealed class EyeLerpingSystem : EntitySystem
         if (!TryComp(uid, out TransformComponent? transform)
             || !TryComp(uid, out EyeComponent? eye)
             || eye.Eye == null
-            || !_mapManager.TryGetGrid(transform.GridEntityId, out var grid))
+            || !_mapManager.TryGetGrid(transform.GridUid, out var grid))
         {
             _toRemove.Add(uid);
             return;

Content.Client/IconSmoothing/IconSmoothComponent.cs

@@ -13,7 +13,7 @@ namespace Content.Client.IconSmoothing
     [RegisterComponent]
     public sealed class IconSmoothComponent : Component
     {
-        public (EntityUid, Vector2i)? LastPosition;
+        public (EntityUid?, Vector2i)? LastPosition;
 
         /// <summary>
         ///     We will smooth with other objects with the same key.

Content.Client/IconSmoothing/IconSmoothSystem.cs

@@ -33,9 +33,9 @@ namespace Content.Client.IconSmoothing
             var xform = Transform(uid);
             if (xform.Anchored)
             {
-                component.LastPosition = _mapManager.TryGetGrid(xform.GridEntityId, out var grid)
+                component.LastPosition = _mapManager.TryGetGrid(xform.GridUid, out var grid)
-                    ? (xform.GridEntityId, grid.TileIndicesFor(xform.Coordinates))
+                    ? (xform.GridUid.Value, grid.TileIndicesFor(xform.Coordinates))
-                    : (EntityUid.Invalid, new Vector2i(0, 0));
+                    : (null, new Vector2i(0, 0));
 
                 DirtyNeighbours(uid, component);
             }
@@ -111,7 +111,7 @@ namespace Content.Client.IconSmoothing
 
             Vector2i pos;
 
-            if (transform.Anchored && _mapManager.TryGetGrid(transform.GridEntityId, out var grid))
+            if (transform.Anchored && _mapManager.TryGetGrid(transform.GridUid, out var grid))
             {
                 pos = grid.CoordinatesToTile(transform.Coordinates);
             }
@@ -191,9 +191,9 @@ namespace Content.Client.IconSmoothing
 
             if (xform.Anchored)
             {
-                if (!_mapManager.TryGetGrid(xform.GridEntityId, out grid))
+                if (!_mapManager.TryGetGrid(xform.GridUid, out grid))
                 {
-                    Logger.Error($"Failed to calculate IconSmoothComponent sprite in {uid} because grid {xform.GridEntityId} was missing.");
+                    Logger.Error($"Failed to calculate IconSmoothComponent sprite in {uid} because grid {xform.GridUid} was missing.");
                     return;
                 }
             }

Content.Client/NodeContainer/NodeVisualizationOverlay.cs

@@ -76,9 +76,10 @@ namespace Content.Client.NodeContainer
             var node = _system.NodeLookup[(groupId, nodeId)];
 
 
-            var gridId = _entityManager.GetComponent<TransformComponent>(node.Entity).GridEntityId;
+            var xform = _entityManager.GetComponent<TransformComponent>(node.Entity);
-            var grid = _mapManager.GetGrid(gridId);
+            if (!_mapManager.TryGetGrid(xform.GridUid, out var grid))
-            var gridTile = grid.TileIndicesFor(_entityManager.GetComponent<TransformComponent>(node.Entity).Coordinates);
+                return;
+            var gridTile = grid.TileIndicesFor(xform.Coordinates);
 
             var sb = new StringBuilder();
             sb.Append($"entity: {node.Entity}\n");

Content.Client/Physics/Controllers/MoverController.cs

@@ -27,7 +27,7 @@ namespace Content.Client.Physics.Controllers
                 return;
             }
 
-            if (xform.GridEntityId != EntityUid.Invalid)
+            if (xform.GridUid != null)
                 mover.LastGridAngle = GetParentGridAngle(xform, mover);
 
             // Essentially we only want to set our mob to predicted so every other entity we just interpolate

Content.Client/Shuttles/UI/RadarControl.cs

@@ -150,15 +150,15 @@ public sealed class RadarControl : Control
         Matrix3 matrix;
 
         // Draw our grid in detail
-        var ourGridId = xform.GridID;
+        var ourGridId = xform.GridUid;
-        if (ourGridId != GridId.Invalid)
+        if (ourGridId != null)
         {
             matrix = xform.InvWorldMatrix;
-            var ourGridFixtures = fixturesQuery.GetComponent(ourGridId);
+            var ourGridFixtures = fixturesQuery.GetComponent(ourGridId.Value);
             // Draw our grid; use non-filled boxes so it doesn't look awful.
             DrawGrid(handle, offsetMatrix, ourGridFixtures, Color.Yellow);
 
-            DrawDocks(handle, xform.GridEntityId, offsetMatrix);
+            DrawDocks(handle, ourGridId.Value, offsetMatrix);
         }
         else
         {

Content.Client/Shuttles/UI/ShuttleConsoleWindow.xaml.cs

@@ -110,13 +110,14 @@ public sealed partial class ShuttleConsoleWindow : FancyWindow,
         DockPorts.DisposeAllChildren();
         DockingScreen.Docks = _docks;
 
-        if (!_entManager.TryGetComponent<TransformComponent>(_entity, out var xform))
+        if (!_entManager.TryGetComponent<TransformComponent>(_entity, out var xform)
+            || !xform.GridUid.HasValue)
         {
             // TODO: Show Placeholder
             return;
         }
 
-        if (_docks.TryGetValue(xform.GridEntityId, out var gridDocks))
+        if (_docks.TryGetValue(xform.GridUid.Value, out var gridDocks))
         {
             var index = 1;
 
@@ -194,7 +195,7 @@ public sealed partial class ShuttleConsoleWindow : FancyWindow,
             DockingScreen.Visible = true;
             DockingScreen.ViewedDock = ent;
             StartAutodockPressed?.Invoke(ent);
-            DockingScreen.GridEntity = xform?.GridEntityId;
+            DockingScreen.GridEntity = xform?.GridUid;
             _selectedDock = obj.Button;
         }
     }
@@ -215,8 +216,8 @@ public sealed partial class ShuttleConsoleWindow : FancyWindow,
         base.Draw(handle);
 
         if (!_entManager.TryGetComponent<TransformComponent>(_entity, out var entXform) ||
-            !_entManager.TryGetComponent<PhysicsComponent>(entXform.GridEntityId, out var gridBody) ||
+            !_entManager.TryGetComponent<PhysicsComponent>(entXform.GridUid, out var gridBody) ||
-            !_entManager.TryGetComponent<TransformComponent>(entXform.GridEntityId, out var gridXform))
+            !_entManager.TryGetComponent<TransformComponent>(entXform.GridUid, out var gridXform))
         {
             return;
         }

Content.IntegrationTests/Tests/SaveLoadSaveTest.cs

@@ -27,7 +27,7 @@ namespace Content.IntegrationTests.Tests
             {
                 // TODO: Properly find the "main" station grid.
                 var grid0 = mapManager.GetAllGrids().First();
-                mapLoader.SaveBlueprint(grid0.GridEntityId, "save load save 1.yml");
+                mapLoader.SaveBlueprint(grid0.Index, "save load save 1.yml");
                 var mapId = mapManager.CreateMap();
                 var grid = mapLoader.LoadBlueprint(mapId, "save load save 1.yml").gridId;
                 mapLoader.SaveBlueprint(grid!.Value, "save load save 2.yml");

Content.MapRenderer/Painters/GridPainter.cs

@@ -90,14 +90,14 @@ namespace Content.MapRenderer.Painters
                 }
 
                 var transform = _sEntityManager.GetComponent<TransformComponent>(entity);
-                if (_cMapManager.TryGetGrid(transform.GridEntityId, out var grid))
+                if (_cMapManager.TryGetGrid(transform.GridUid, out var grid))
                 {
                     var position = transform.LocalPosition;
 
                     var (x, y) = TransformLocalPosition(position, grid);
                     var data = new EntityData(sprite, x, y);
 
-                    components.GetOrAdd(transform.GridEntityId, _ => new List<EntityData>()).Add(data);
+                    components.GetOrAdd(transform.GridUid.Value, _ => new List<EntityData>()).Add(data);
                 }
             }
 

Content.Server/AI/Operators/Inventory/InteractWithEntityOperator.cs

@@ -26,7 +26,7 @@ namespace Content.Server.AI.Operators.Inventory
         {
             var targetTransform = _entMan.GetComponent<TransformComponent>(_useTarget);
 
-            if (targetTransform.GridEntityId != _entMan.GetComponent<TransformComponent>(_owner).GridEntityId)
+            if (targetTransform.GridUid != _entMan.GetComponent<TransformComponent>(_owner).GridUid)
             {
                 return Outcome.Failed;
             }

Content.Server/AI/Pathfinding/Accessible/AiReachableSystem.cs

@@ -168,10 +168,10 @@ namespace Content.Server.AI.Pathfinding.Accessible
         {
             var xform = EntityManager.GetComponent<TransformComponent>(target);
             // TODO: Handle this gracefully instead of just failing.
-            if (!xform.GridEntityId.IsValid())
+            if (xform.GridUid == null)
                 return false;
 
-            var targetTile = _mapManager.GetGrid(xform.GridEntityId).GetTileRef(xform.Coordinates);
+            var targetTile = _mapManager.GetGrid(xform.GridUid.Value).GetTileRef(xform.Coordinates);
             var targetNode = _pathfindingSystem.GetNode(targetTile);
 
             var collisionMask = 0;
@@ -206,10 +206,10 @@ namespace Content.Server.AI.Pathfinding.Accessible
         {
             var xform = EntityManager.GetComponent<TransformComponent>(entity);
 
-            if (xform.GridEntityId != targetNode.TileRef.GridUid)
+            if (xform.GridUid != targetNode.TileRef.GridUid || xform.GridUid == null)
                 return false;
 
-            var entityTile = _mapManager.GetGrid(xform.GridEntityId).GetTileRef(xform.Coordinates);
+            var entityTile = _mapManager.GetGrid(xform.GridUid.Value).GetTileRef(xform.Coordinates);
             var entityNode = _pathfindingSystem.GetNode(entityTile);
             var entityRegion = GetRegion(entityNode);
             var targetRegion = GetRegion(targetNode);
@@ -421,12 +421,12 @@ namespace Content.Server.AI.Pathfinding.Accessible
         {
             var xform = EntityManager.GetComponent<TransformComponent>(entity);
 
-            if (!xform.GridEntityId.IsValid())
+            if (xform.GridUid == null)
             {
                 return null;
             }
 
-            var entityTile = _mapManager.GetGrid(xform.GridEntityId).GetTileRef(xform.Coordinates);
+            var entityTile = _mapManager.GetGrid(xform.GridUid.Value).GetTileRef(xform.Coordinates);
             var entityNode = _pathfindingSystem.GetNode(entityTile);
             return GetRegion(entityNode);
         }

Content.Server/AI/Pathfinding/PathfindingSystem.Grid.cs

@@ -129,7 +129,7 @@ public sealed partial class PathfindingSystem
 
     private bool IsRelevant(TransformComponent xform, PhysicsComponent physics)
     {
-        return xform.GridEntityId != EntityUid.Invalid && (TrackedCollisionLayers & physics.CollisionLayer) != 0;
+        return xform.GridUid != null && (TrackedCollisionLayers & physics.CollisionLayer) != 0;
     }
 
     /// <summary>
@@ -143,7 +143,7 @@ public sealed partial class PathfindingSystem
             !Resolve(entity, ref physics, false)) return;
 
         if (!IsRelevant(xform, physics) ||
-            !_mapManager.TryGetGrid(xform.GridEntityId, out var grid))
+            !_mapManager.TryGetGrid(xform.GridUid, out var grid))
         {
             return;
         }
@@ -158,7 +158,7 @@ public sealed partial class PathfindingSystem
     private void OnEntityRemove(EntityUid entity, TransformComponent? xform = null)
     {
         if (!Resolve(entity, ref xform, false) ||
-            !_mapManager.TryGetGrid(xform.GridEntityId, out var grid)) return;
+            !_mapManager.TryGetGrid(xform.GridUid, out var grid)) return;
 
         var node = GetNode(grid.GetTileRef(xform.Coordinates));
         node.RemoveEntity(entity);
@@ -166,7 +166,7 @@ public sealed partial class PathfindingSystem
 
     private void OnEntityRemove(EntityUid entity, EntityCoordinates coordinates)
     {
-        var gridId = coordinates.GetGridEntityId(EntityManager);
+        var gridId = coordinates.GetGridUid(EntityManager);
         if (!_mapManager.TryGetGrid(gridId, out var grid)) return;
 
         var node = GetNode(grid.GetTileRef(coordinates));
@@ -175,13 +175,13 @@ public sealed partial class PathfindingSystem
 
     private PathfindingNode? GetNode(TransformComponent xform)
     {
-        if (!_mapManager.TryGetGrid(xform.GridEntityId, out var grid)) return null;
+        if (!_mapManager.TryGetGrid(xform.GridUid, out var grid)) return null;
         return GetNode(grid.GetTileRef(xform.Coordinates));
     }
 
     private PathfindingNode? GetNode(EntityCoordinates coordinates)
     {
-        if (!_mapManager.TryGetGrid(coordinates.GetGridEntityId(EntityManager), out var grid)) return null;
+        if (!_mapManager.TryGetGrid(coordinates.GetGridUid(EntityManager), out var grid)) return null;
         return GetNode(grid.GetTileRef(coordinates));
     }
 
@@ -215,8 +215,10 @@ public sealed partial class PathfindingSystem
     // Also look at increasing tile cost the more physics entities are on it
     public bool CanTraverse(EntityUid entity, EntityCoordinates coordinates)
     {
-        var gridId = coordinates.GetGridEntityId(EntityManager);
+        var gridId = coordinates.GetGridUid(EntityManager);
-        var tile = _mapManager.GetGrid(gridId).GetTileRef(coordinates);
+        if (gridId == null)
+                return false;
+        var tile = _mapManager.GetGrid(gridId.Value).GetTileRef(coordinates);
         var node = GetNode(tile);
         return CanTraverse(entity, node);
     }

Content.Server/AI/Steering/AiSteeringSystem.cs

@@ -242,7 +242,8 @@ namespace Content.Server.AI.Steering
             if (Deleted(entity) ||
                 !EntityManager.TryGetComponent(entity, out AiControllerComponent? controller) ||
                 !controller.CanMove ||
-                !EntityManager.GetComponent<TransformComponent>(entity).GridEntityId.IsValid())
+                !TryComp(entity, out TransformComponent? xform) ||
+                xform.GridUid == null)
             {
                 return SteeringStatus.NoPath;
             }
@@ -255,7 +256,7 @@ namespace Content.Server.AI.Steering
                 return SteeringStatus.NoPath;
             }
 
-            if (_mapManager.IsGridPaused(EntityManager.GetComponent<TransformComponent>(entity).GridEntityId))
+            if (_mapManager.IsGridPaused(xform.GridUid.Value))
             {
                 controller.VelocityDir = Vector2.Zero;
                 return SteeringStatus.Pending;
@@ -263,14 +264,14 @@ namespace Content.Server.AI.Steering
 
             // Validation
             // Check if we can even arrive -> Currently only samegrid movement supported
-            if (EntityManager.GetComponent<TransformComponent>(entity).GridEntityId != steeringRequest.TargetGrid.GetGridEntityId(EntityManager))
+            if (xform.GridUid != steeringRequest.TargetGrid.GetGridUid(EntityManager))
             {
                 controller.VelocityDir = Vector2.Zero;
                 return SteeringStatus.NoPath;
             }
 
             // Check if we have arrived
-            var targetDistance = (EntityManager.GetComponent<TransformComponent>(entity).MapPosition.Position - steeringRequest.TargetMap.Position).Length;
+            var targetDistance = (xform.MapPosition.Position - steeringRequest.TargetMap.Position).Length;
             steeringRequest.TimeUntilInteractionCheck -= frameTime;
 
             if (targetDistance <= steeringRequest.ArrivalDistance && steeringRequest.TimeUntilInteractionCheck <= 0.0f)
@@ -407,9 +408,13 @@ namespace Content.Server.AI.Steering
                 return;
             }
 
+            var xform = EntityManager.GetComponent<TransformComponent>(entity);
+            if (xform.GridUid == null)
+                return;
+
             var cancelToken = new CancellationTokenSource();
-            var gridManager = _mapManager.GetGrid(EntityManager.GetComponent<TransformComponent>(entity).GridEntityId);
+            var gridManager = _mapManager.GetGrid(xform.GridUid.Value);
-            var startTile = gridManager.GetTileRef(EntityManager.GetComponent<TransformComponent>(entity).Coordinates);
+            var startTile = gridManager.GetTileRef(xform.Coordinates);
             var endTile = gridManager.GetTileRef(steeringRequest.TargetGrid);
             var collisionMask = 0;
             if (EntityManager.TryGetComponent(entity, out IPhysBody? physics))
@@ -439,7 +444,10 @@ namespace Content.Server.AI.Steering
         {
             _pathfindingRequests.Remove(entity);
 
-            var entityTile = _mapManager.GetGrid(EntityManager.GetComponent<TransformComponent>(entity).GridEntityId).GetTileRef(EntityManager.GetComponent<TransformComponent>(entity).Coordinates);
+            var xform = EntityManager.GetComponent<TransformComponent>(entity);
+            if (xform.GridUid == null)
+                return;
+            var entityTile = _mapManager.GetGrid(xform.GridUid.Value).GetTileRef(xform.Coordinates);
             var tile = path.Dequeue();
             var closestDistance = PathfindingHelpers.OctileDistance(entityTile, tile);
 
@@ -508,7 +516,12 @@ namespace Content.Server.AI.Steering
         {
             if (_paths[entity].Count == 0) return;
             var nextTile = dequeue ? _paths[entity].Dequeue() : _paths[entity].Peek();
-            var nextGrid = _mapManager.GetGrid(EntityManager.GetComponent<TransformComponent>(entity).GridEntityId).GridTileToLocal(nextTile.GridIndices);
+
+            var xform = EntityManager.GetComponent<TransformComponent>(entity);
+            if (xform.GridUid == null)
+                return;
+
+            var nextGrid = _mapManager.GetGrid(xform.GridUid.Value).GridTileToLocal(nextTile.GridIndices);
             _nextGrid[entity] = nextGrid;
         }
 
@@ -630,8 +643,13 @@ namespace Content.Server.AI.Steering
             var avoidanceVector = Vector2.Zero;
             var checkTiles = new HashSet<TileRef>();
             var avoidTiles = new HashSet<TileRef>();
-            var entityGridCoords = EntityManager.GetComponent<TransformComponent>(entity).Coordinates;
+
-            var grid = _mapManager.GetGrid(EntityManager.GetComponent<TransformComponent>(entity).GridEntityId);
+            var xform = EntityManager.GetComponent<TransformComponent>(entity);
+            if (xform.GridUid == null)
+                return default;
+
+            var entityGridCoords = xform.Coordinates;
+            var grid = _mapManager.GetGrid(xform.GridUid.Value);
             var currentTile = grid.GetTileRef(entityGridCoords);
             var halfwayTile = grid.GetTileRef(entityGridCoords.Offset(direction / 2));
             var nextTile = grid.GetTileRef(entityGridCoords.Offset(direction));

Content.Server/AI/Utility/Actions/Idle/WanderAndWait.cs

@@ -51,10 +51,12 @@ namespace Content.Server.AI.Utility.Actions.Idle
             };
         }
 
-        private EntityCoordinates FindRandomGrid(IRobustRandom robustRandom)
+        private EntityCoordinates FindRandomGrid(IRobustRandom robustRandom, IEntityManager? entMan = null)
         {
+            IoCManager.Resolve(ref entMan);
+
             // Very inefficient (should weight each region by its node count) but better than the old system
-            var reachableSystem = EntitySystem.Get<AiReachableSystem>();
+            var reachableSystem = entMan.EntitySysManager.GetEntitySystem<AiReachableSystem>();
             var reachableArgs = ReachableArgs.GetArgs(Owner);
             var entityRegion = reachableSystem.GetRegion(Owner);
             var reachableRegions = reachableSystem.GetReachableRegions(reachableArgs, entityRegion);
@@ -76,9 +78,11 @@ namespace Content.Server.AI.Utility.Actions.Idle
             }
 
             var targetNode = robustRandom.Pick(reachableNodes);
-            var mapManager = IoCManager.Resolve<IMapManager>();
+
-            var grid = mapManager.GetGrid(IoCManager.Resolve<IEntityManager>().GetComponent<TransformComponent>(Owner).GridEntityId);
+            if (!entMan.TryGetComponent(entMan.GetComponent<TransformComponent>(Owner).GridUid, out IMapGridComponent? grid))
-            var targetGrid = grid.GridTileToLocal(targetNode.TileRef.GridIndices);
+                return default;
+
+            var targetGrid = grid.Grid.GridTileToLocal(targetNode.TileRef.GridIndices);
 
             return targetGrid;
         }

Content.Server/AI/Utility/Considerations/Movement/TargetDistanceCon.cs

@@ -11,7 +11,7 @@ namespace Content.Server.AI.Utility.Considerations.Movement
             var entities = IoCManager.Resolve<IEntityManager>();
 
             if (context.GetState<TargetEntityState>().GetValue() is not {Valid: true} target || entities.Deleted(target) ||
-                entities.GetComponent<TransformComponent>(target).GridEntityId != entities.GetComponent<TransformComponent>(self).GridEntityId)
+                entities.GetComponent<TransformComponent>(target).GridUid != entities.GetComponent<TransformComponent>(self).GridUid)
             {
                 return 0.0f;
             }

Content.Server/AI/Utils/Visibility.cs

@@ -22,7 +22,7 @@ namespace Content.Server.AI.Utils
             {
                 var transform = entityManager.GetComponent<TransformComponent>(entity);
 
-                if (transform.Coordinates.GetGridEntityId(entityManager) != grid.GetGridEntityId(entityManager))
+                if (transform.Coordinates.GetGridUid(entityManager) != grid.GetGridUid(entityManager))
                 {
                     continue;
                 }

Content.Server/AME/AntimatterEngineSystem.cs

@@ -90,7 +90,7 @@ namespace Content.Server.AME
             if (!_toolSystem.HasQuality(args.Used, component.QualityNeeded))
                 return;
 
-            if (!_mapManager.TryGetGrid(args.ClickLocation.GetGridEntityId(EntityManager), out var mapGrid))
+            if (!_mapManager.TryGetGrid(args.ClickLocation.GetGridUid(EntityManager), out var mapGrid))
                 return; // No AME in space.
 
             var snapPos = mapGrid.TileIndicesFor(args.ClickLocation);

Content.Server/Administration/Commands/WarpCommand.cs

@@ -52,7 +52,7 @@ namespace Content.Server.Administration.Commands
 
                 var mapManager = IoCManager.Resolve<IMapManager>();
                 var currentMap = entMan.GetComponent<TransformComponent>(playerEntity).MapID;
-                var currentGrid = entMan.GetComponent<TransformComponent>(playerEntity).GridEntityId;
+                var currentGrid = entMan.GetComponent<TransformComponent>(playerEntity).GridUid;
 
                 var found = entMan.EntityQuery<WarpPointComponent>(true)
                     .Where(p => p.Location == location)
@@ -62,8 +62,8 @@ namespace Content.Server.Administration.Commands
                         // Sort so that warp points on the same grid/map are first.
                         // So if you have two maps loaded with the same warp points,
                         // it will prefer the warp points on the map you're currently on.
-                        var aGrid = a.GetGridEntityId(entMan);
+                        var aGrid = a.GetGridUid(entMan);
-                        var bGrid = b.GetGridEntityId(entMan);
+                        var bGrid = b.GetGridUid(entMan);
 
                         if (aGrid == bGrid)
                         {
@@ -102,7 +102,7 @@ namespace Content.Server.Administration.Commands
                     }))
                     .FirstOrDefault();
 
-                var entityUid = found.GetGridEntityId(entMan);
+                var entityUid = found.GetGridUid(entMan);
                 if (entityUid != EntityUid.Invalid)
                 {
                     entMan.GetComponent<TransformComponent>(playerEntity).Coordinates = found;

Content.Server/Atmos/Commands/DeleteGasCommand.cs

@@ -18,7 +18,7 @@ namespace Content.Server.Atmos.Commands
         public void Execute(IConsoleShell shell, string argStr, string[] args)
         {
             var player = shell.Player as IPlayerSession;
-            EntityUid gridId;
+            EntityUid? gridId;
             Gas? gas = null;
 
             var entMan = IoCManager.Resolve<IEntityManager>();
@@ -39,9 +39,9 @@ namespace Content.Server.Atmos.Commands
                         return;
                     }
 
-                    gridId = entMan.GetComponent<TransformComponent>(playerEntity).GridEntityId;
+                    gridId = entMan.GetComponent<TransformComponent>(playerEntity).GridUid;
 
-                    if (gridId == EntityUid.Invalid)
+                    if (gridId == null)
                     {
                         shell.WriteLine("You aren't on a grid to delete gas from.");
                         return;
@@ -66,9 +66,9 @@ namespace Content.Server.Atmos.Commands
                             return;
                         }
 
-                        gridId = entMan.GetComponent<TransformComponent>(playerEntity).GridEntityId;
+                        gridId = entMan.GetComponent<TransformComponent>(playerEntity).GridUid;
 
-                        if (gridId == EntityUid.Invalid)
+                        if (gridId == null)
                         {
                             shell.WriteLine("You aren't on a grid to delete gas from.");
                             return;
@@ -98,7 +98,7 @@ namespace Content.Server.Atmos.Commands
 
                     gridId = first;
 
-                    if (gridId == EntityUid.Invalid)
+                    if (gridId.Value.IsValid())
                     {
                         shell.WriteLine($"{gridId} is not a valid grid id.");
                         return;
@@ -134,7 +134,7 @@ namespace Content.Server.Atmos.Commands
 
             if (gas == null)
             {
-                foreach (var tile in atmosphereSystem.GetAllTileMixtures(gridId, true))
+                foreach (var tile in atmosphereSystem.GetAllTileMixtures(gridId.Value, true))
                 {
                     if (tile.Immutable) continue;
 
@@ -146,7 +146,7 @@ namespace Content.Server.Atmos.Commands
             }
             else
             {
-                foreach (var tile in atmosphereSystem.GetAllTileMixtures(gridId, true))
+                foreach (var tile in atmosphereSystem.GetAllTileMixtures(gridId.Value, true))
                 {
                     if (tile.Immutable) continue;
 

Content.Server/Atmos/EntitySystems/AirtightSystem.cs

@@ -44,7 +44,7 @@ namespace Content.Server.Atmos.EntitySystems
             var xform = Transform(uid);
 
             // If the grid is deleting no point updating atmos.
-            if (_mapManager.TryGetGrid(xform.GridEntityId, out var grid))
+            if (_mapManager.TryGetGrid(xform.GridUid, out var grid))
             {
                 if (MetaData(grid.GridEntityId).EntityLifeStage > EntityLifeStage.MapInitialized) return;
             }
@@ -56,15 +56,17 @@ namespace Content.Server.Atmos.EntitySystems
         {
             var xform = Transform(uid);
 
-            var gridId = xform.GridEntityId;
+            if (!TryComp(xform.GridUid, out IMapGridComponent? grid))
+                return;
+
+            var gridId = xform.GridUid;
             var coords = xform.Coordinates;
 
-            var grid = _mapManager.GetGrid(gridId);
+            var tilePos = grid.Grid.TileIndicesFor(coords);
-            var tilePos = grid.TileIndicesFor(coords);
 
             // Update and invalidate new position.
-            airtight.LastPosition = (gridId, tilePos);
+            airtight.LastPosition = (gridId.Value, tilePos);
-            InvalidatePosition(gridId, tilePos);
+            InvalidatePosition(gridId.Value, tilePos);
         }
 
         private void OnAirtightReAnchor(EntityUid uid, AirtightComponent airtight, ref ReAnchorEvent args)
@@ -100,11 +102,10 @@ namespace Content.Server.Atmos.EntitySystems
         {
             if (!Resolve(airtight.Owner, ref xform)) return;
 
-            if (!xform.Anchored || !xform.GridEntityId.IsValid())
+            if (!xform.Anchored || !_mapManager.TryGetGrid(xform.GridUid, out var grid))
                 return;
 
-            var grid = _mapManager.GetGrid(xform.GridEntityId);
+            airtight.LastPosition = (xform.GridUid.Value, grid.TileIndicesFor(xform.Coordinates));
-            airtight.LastPosition = (xform.GridEntityId, grid.TileIndicesFor(xform.Coordinates));
             InvalidatePosition(airtight.LastPosition.Item1, airtight.LastPosition.Item2, airtight.FixVacuum && !airtight.AirBlocked);
         }
 

Content.Server/Atmos/EntitySystems/AtmosphereSystem.Grid.cs

@@ -125,7 +125,7 @@ namespace Content.Server.Atmos.EntitySystems
         /// </summary>
         /// <param name="grid">Grid to be checked.</param>
         /// <returns>Whether the grid has a simulated atmosphere.</returns>
-        public bool IsSimulatedGrid(EntityUid grid)
+        public bool IsSimulatedGrid(EntityUid? grid)
         {
             if (!_mapManager.TryGetGrid(grid, out var mapGrid))
                 return false;
@@ -1376,7 +1376,7 @@ namespace Content.Server.Atmos.EntitySystems
 
         public bool AddAtmosDevice(AtmosDeviceComponent atmosDevice)
         {
-            var grid = Comp<TransformComponent>(atmosDevice.Owner).GridEntityId;
+            var grid = Comp<TransformComponent>(atmosDevice.Owner).GridUid;
 
             if (!_mapManager.TryGetGrid(grid, out var mapGrid))
                 return false;
@@ -1578,7 +1578,7 @@ namespace Content.Server.Atmos.EntitySystems
                 return false;
             }
 
-            var gridId = coordinates.GetGridEntityId(EntityManager);
+            var gridId = coordinates.GetGridUid(EntityManager);
 
             if (!_mapManager.TryGetGrid(gridId, out var grid))
             {
@@ -1586,7 +1586,7 @@ namespace Content.Server.Atmos.EntitySystems
                 return false;
             }
 
-            tuple = (gridId, grid.TileIndicesFor(coordinates));
+            tuple = (gridId.Value, grid.TileIndicesFor(coordinates));
             return true;
         }
 

Content.Server/Atmos/EntitySystems/AtmosphereSystem.HighPressureDelta.cs

@@ -161,7 +161,6 @@ namespace Content.Server.Atmos.EntitySystems
                         xforms.GetComponent(entity),
                         body);
                 }
-
             }
         }
 

Content.Server/Atmos/Piping/EntitySystems/AtmosPipeAppearanceSystem.cs

@@ -29,7 +29,7 @@ public sealed class AtmosPipeAppearanceSystem : EntitySystem
         if (!Resolve(uid, ref appearance, ref container, ref xform, false))
             return;
 
-        if (!_mapManager.TryGetGrid(xform.GridEntityId, out var grid))
+        if (!_mapManager.TryGetGrid(xform.GridUid, out var grid))
             return;
 
         // get connected entities

Content.Server/Atmos/Piping/Unary/EntitySystems/GasPortableSystem.cs

@@ -30,7 +30,7 @@ namespace Content.Server.Atmos.Piping.Unary.EntitySystems
                 return;
 
             // If we can't find any ports, cancel the anchoring.
-            if(!FindGasPortIn(transform.GridEntityId, transform.Coordinates, out _))
+            if(!FindGasPortIn(transform.GridUid, transform.Coordinates, out _))
                 args.Cancel();
         }
 
@@ -50,15 +50,13 @@ namespace Content.Server.Atmos.Piping.Unary.EntitySystems
             }
         }
 
-        private bool FindGasPortIn(EntityUid gridId, EntityCoordinates coordinates, [NotNullWhen(true)] out GasPortComponent? port)
+        private bool FindGasPortIn(EntityUid? gridId, EntityCoordinates coordinates, [NotNullWhen(true)] out GasPortComponent? port)
         {
             port = null;
 
-            if (!gridId.IsValid())
+            if (!_mapManager.TryGetGrid(gridId, out var grid))
                 return false;
 
-            var grid = _mapManager.GetGrid(gridId);
-
             foreach (var entityUid in grid.GetLocal(coordinates))
             {
                 if (EntityManager.TryGetComponent<GasPortComponent>(entityUid, out port))

Content.Server/Chemistry/Components/SolutionAreaEffectComponent.cs

@@ -69,7 +69,11 @@ namespace Content.Server.Chemistry.Components
 
             var xform = _entities.GetComponent<TransformComponent>(Owner);
             var solSys = _systems.GetEntitySystem<SolutionContainerSystem>();
-            var grid = MapManager.GetGrid(xform.GridEntityId);
+
+            if (!_entities.TryGetComponent(xform.GridUid, out IMapGridComponent? gridComp))
+                return;
+
+            var grid = gridComp.Grid;
             var origin = grid.TileIndicesFor(xform.Coordinates);
 
             DebugTools.Assert(xform.Anchored, "Area effect entity prototypes must be anchored.");
@@ -141,14 +145,17 @@ namespace Content.Server.Chemistry.Components
         /// with the other area effects from the inception.</param>
         public void React(float averageExposures)
         {
-            if (!EntitySystem.Get<SolutionContainerSystem>().TryGetSolution(Owner, SolutionName, out var solution))
+
+            if (!_entities.EntitySysManager.GetEntitySystem<SolutionContainerSystem>().TryGetSolution(Owner, SolutionName, out var solution))
                 return;
 
-            var chemistry = EntitySystem.Get<ReactiveSystem>();
             var xform = _entities.GetComponent<TransformComponent>(Owner);
-            var mapGrid = MapManager.GetGrid(xform.GridEntityId);
+            if (!MapManager.TryGetGrid(xform.GridUid, out var mapGrid))
+                return;
+
             var tile = mapGrid.GetTileRef(xform.Coordinates.ToVector2i(_entities, MapManager));
-            var lookup = EntitySystem.Get<EntityLookupSystem>();
+            var chemistry = _entities.EntitySysManager.GetEntitySystem<ReactiveSystem>();
+            var lookup = _entities.EntitySysManager.GetEntitySystem<EntityLookupSystem>();
 
             var solutionFraction = 1 / Math.Floor(averageExposures);
 

Content.Server/Chemistry/EntitySystems/VaporSystem.cs

@@ -90,16 +90,17 @@ namespace Content.Server.Chemistry.EntitySystems
                 return;
 
             var entity = vapor.Owner;
+            var xform = Transform(entity);
 
             vapor.Timer += frameTime;
             vapor.ReactTimer += frameTime;
 
-            if (vapor.ReactTimer >= ReactTime && EntityManager.GetComponent<TransformComponent>(vapor.Owner).GridEntityId.IsValid())
+            if (vapor.ReactTimer >= ReactTime && TryComp(xform.GridUid, out IMapGridComponent? gridComp))
             {
                 vapor.ReactTimer = 0;
-                var mapGrid = _mapManager.GetGrid(EntityManager.GetComponent<TransformComponent>(entity).GridEntityId);
 
-                var tile = mapGrid.GetTileRef(EntityManager.GetComponent<TransformComponent>(entity).Coordinates.ToVector2i(EntityManager, _mapManager));
+
+                var tile = gridComp.Grid.GetTileRef(xform.Coordinates.ToVector2i(EntityManager, _mapManager));
                 foreach (var reagentQuantity in contents.Contents.ToArray())
                 {
                     if (reagentQuantity.Quantity == FixedPoint2.Zero) continue;
@@ -111,7 +112,7 @@ namespace Content.Server.Chemistry.EntitySystems
 
             // Check if we've reached our target.
             if (!vapor.Reached &&
-                vapor.Target.TryDistance(EntityManager, EntityManager.GetComponent<TransformComponent>(entity).Coordinates, out var distance) &&
+                vapor.Target.TryDistance(EntityManager, xform.Coordinates, out var distance) &&
                 distance <= 0.5f)
             {
                 vapor.Reached = true;

Content.Server/Construction/Commands/FixRotationsCommand.cs

@@ -21,7 +21,7 @@ namespace Content.Server.Construction.Commands
         {
             var player = shell.Player as IPlayerSession;
             var entityManager = IoCManager.Resolve<IEntityManager>();
-            EntityUid gridId;
+            EntityUid? gridId;
             var xformQuery = entityManager.GetEntityQuery<TransformComponent>();
 
             switch (args.Length)
@@ -33,7 +33,7 @@ namespace Content.Server.Construction.Commands
                         return;
                     }
 
-                    gridId = xformQuery.GetComponent(playerEntity).GridEntityId;
+                    gridId = xformQuery.GetComponent(playerEntity).GridUid;
                     break;
                 case 1:
                     if (!EntityUid.TryParse(args[0], out var id))

Content.Server/Construction/Commands/TileReplaceCommand.cs

@@ -21,7 +21,7 @@ sealed class TileReplaceCommand : IConsoleCommand
     {
         var player = shell.Player as IPlayerSession;
         var entityManager = IoCManager.Resolve<IEntityManager>();
-        EntityUid gridId;
+        EntityUid? gridId;
         string tileIdA = "";
         string tileIdB = "";
 
@@ -34,7 +34,7 @@ sealed class TileReplaceCommand : IConsoleCommand
                     return;
                 }
 
-                gridId = entityManager.GetComponent<TransformComponent>(playerEntity).GridEntityId;
+                gridId = entityManager.GetComponent<TransformComponent>(playerEntity).GridUid;
                 tileIdA = args[0];
                 tileIdB = args[1];
                 break;

Content.Server/Construction/Commands/TileWallsCommand.cs

@@ -24,7 +24,7 @@ namespace Content.Server.Construction.Commands
         {
             var player = shell.Player as IPlayerSession;
             var entityManager = IoCManager.Resolve<IEntityManager>();
-            EntityUid gridId;
+            EntityUid? gridId;
 
             switch (args.Length)
             {
@@ -35,7 +35,7 @@ namespace Content.Server.Construction.Commands
                         return;
                     }
 
-                    gridId = entityManager.GetComponent<TransformComponent>(playerEntity).GridEntityId;
+                    gridId = entityManager.GetComponent<TransformComponent>(playerEntity).GridUid;
                     break;
                 case 1:
                     if (!EntityUid.TryParse(args[0], out var id))

Content.Server/Construction/Conditions/ComponentInTile.cs

@@ -43,8 +43,11 @@ namespace Content.Server.Construction.Conditions
             var type = IoCManager.Resolve<IComponentFactory>().GetRegistration(Component).Type;
 
             var transform = entityManager.GetComponent<TransformComponent>(uid);
+            if (transform.GridUid == null)
+                return false;
+
             var indices = transform.Coordinates.ToVector2i(entityManager, IoCManager.Resolve<IMapManager>());
-            var entities = indices.GetEntitiesInTile(transform.GridEntityId, LookupFlags.Approximate | LookupFlags.Anchored, EntitySystem.Get<EntityLookupSystem>());
+            var entities = indices.GetEntitiesInTile(transform.GridUid.Value, LookupFlags.Approximate | LookupFlags.Anchored, EntitySystem.Get<EntityLookupSystem>());
 
             foreach (var ent in entities)
             {

Content.Server/Coordinates/Helpers/SnapgridHelper.cs

@@ -15,7 +15,7 @@ namespace Content.Server.Coordinates.Helpers
         {
             IoCManager.Resolve(ref entMan, ref mapManager);
 
-            var gridId = coordinates.GetGridEntityId(entMan);
+            var gridId = coordinates.GetGridId(entMan);
 
             var tileSize = 1f;
 

Content.Server/Decals/DecalSystem.cs

@@ -168,16 +168,16 @@ namespace Content.Server.Decals
             if (!ev.Coordinates.IsValid(EntityManager))
                 return;
 
-            var gridId = ev.Coordinates.GetGridEntityId(EntityManager);
+            var gridId = ev.Coordinates.GetGridUid(EntityManager);
 
-            if (!gridId.IsValid())
+            if (gridId == null)
                 return;
 
             // remove all decals on the same tile
-            foreach (var (uid, decal) in GetDecalsInRange(gridId, ev.Coordinates.Position))
+            foreach (var (uid, decal) in GetDecalsInRange(gridId.Value, ev.Coordinates.Position))
             {
                 var chunkIndices = GetChunkIndices(decal.Coordinates);
-                RemoveDecal(gridId, uid);
+                RemoveDecal(gridId.Value, uid);
             }
         }
 
@@ -205,21 +205,21 @@ namespace Content.Server.Decals
             if (!PrototypeManager.HasIndex<DecalPrototype>(decal.Id))
                 return false;
 
-            var gridId = coordinates.GetGridEntityId(EntityManager);
+            var gridId = coordinates.GetGridUid(EntityManager);
             if (!MapManager.TryGetGrid(gridId, out var grid))
                 return false;
 
             if (grid.GetTileRef(coordinates).IsSpace(_tileDefMan))
                 return false;
 
-            var chunkCollection = DecalGridChunkCollection(gridId);
+            var chunkCollection = DecalGridChunkCollection(gridId.Value);
             uid = chunkCollection.NextUid++;
             var chunkIndices = GetChunkIndices(decal.Coordinates);
             if(!chunkCollection.ChunkCollection.ContainsKey(chunkIndices))
                 chunkCollection.ChunkCollection[chunkIndices] = new();
             chunkCollection.ChunkCollection[chunkIndices][uid.Value] = decal;
-            ChunkIndex[gridId][uid.Value] = chunkIndices;
+            ChunkIndex[gridId.Value][uid.Value] = chunkIndices;
-            DirtyChunk(gridId, chunkIndices);
+            DirtyChunk(gridId.Value, chunkIndices);
 
             return true;
         }
@@ -250,7 +250,11 @@ namespace Content.Server.Decals
 
         public bool SetDecalPosition(EntityUid gridId, uint uid, EntityCoordinates coordinates)
         {
-            return SetDecalPosition(gridId, uid, coordinates.GetGridEntityId(EntityManager), coordinates.Position);
+            var newGridId = coordinates.GetGridUid(EntityManager);
+            if (newGridId == null)
+                return false;
+
+            return SetDecalPosition(gridId, uid, newGridId.Value, coordinates.Position);
         }
 
         public bool SetDecalPosition(EntityUid gridId, uint uid, EntityUid newGridId, Vector2 position)

Content.Server/DeviceNetwork/Systems/WiredNetworkSystem.cs

@@ -17,7 +17,7 @@ namespace Content.Server.DeviceNetwork.Systems
         /// </summary>
         private void OnBeforePacketSent(EntityUid uid, WiredNetworkComponent component, BeforePacketSentEvent args)
         {
-            if (EntityManager.GetComponent<TransformComponent>(uid).GridEntityId != args.SenderTransform.GridEntityId)
+            if (EntityManager.GetComponent<TransformComponent>(uid).GridUid != args.SenderTransform.GridUid)
             {
                 args.Cancel();
             }

Content.Server/Disposal/Tube/DisposalTubeSystem.cs

@@ -125,8 +125,11 @@ namespace Content.Server.Disposal.Tube
                 return null;
             var oppositeDirection = nextDirection.GetOpposite();
 
-            var grid = _mapManager.GetGrid(EntityManager.GetComponent<TransformComponent>(targetTube.Owner).GridEntityId);
+            var xform = Transform(targetTube.Owner);
-            var position = EntityManager.GetComponent<TransformComponent>(targetTube.Owner).Coordinates;
+            if (!_mapManager.TryGetGrid(xform.GridUid, out var grid))
+                return null;
+
+            var position = xform.Coordinates;
             foreach (var entity in grid.GetInDir(position, nextDirection))
             {
                 if (!EntityManager.TryGetComponent(entity, out IDisposalTubeComponent? tube))

Content.Server/Disposal/Unit/EntitySystems/DisposableSystem.cs

@@ -34,7 +34,7 @@ namespace Content.Server.Disposal.Unit.EntitySystems
             // *This is on purpose.*
 
             DisposalUnitComponent? duc = null;
-            if (_mapManager.TryGetGrid(holderTransform.GridEntityId, out var grid))
+            if (_mapManager.TryGetGrid(holderTransform.GridUid, out var grid))
             {
                 foreach (var contentUid in grid.GetLocal(holderTransform.Coordinates))
                 {

Content.Server/Disposal/Unit/EntitySystems/DisposalUnitSystem.cs

@@ -477,9 +477,12 @@ namespace Content.Server.Disposal.Unit.EntitySystems
                 return false;
             }
 
-            var grid = _mapManager.GetGrid(EntityManager.GetComponent<TransformComponent>(component.Owner).GridEntityId);
+            var xform = Transform(component.Owner);
-            var coords = EntityManager.GetComponent<TransformComponent>(component.Owner).Coordinates;
+            if (!TryComp(xform.GridUid, out IMapGridComponent? grid))
-            var entry = grid.GetLocal(coords)
+                return false;
+
+            var coords = xform.Coordinates;
+            var entry = grid.Grid.GetLocal(coords)
                 .FirstOrDefault(entity => EntityManager.HasComponent<DisposalEntryComponent>(entity));
 
             if (entry == default)
@@ -490,7 +493,7 @@ namespace Content.Server.Disposal.Unit.EntitySystems
             var air = component.Air;
             var entryComponent = EntityManager.GetComponent<DisposalEntryComponent>(entry);
 
-            if (_atmosSystem.GetTileMixture(EntityManager.GetComponent<TransformComponent>(component.Owner).Coordinates, true) is {Temperature: > 0} environment)
+            if (_atmosSystem.GetTileMixture(xform.Coordinates, true) is {Temperature: > 0} environment)
             {
                 var transferMoles = 0.1f * (0.25f * Atmospherics.OneAtmosphere * 1.01f - air.Pressure) * air.Volume / (environment.Temperature * Atmospherics.R);
 

Content.Server/Engineering/EntitySystems/SpawnAfterInteractSystem.cs

@@ -30,7 +30,7 @@ namespace Content.Server.Engineering.EntitySystems
                 return;
             if (string.IsNullOrEmpty(component.Prototype))
                 return;
-            if (!_mapManager.TryGetGrid(args.ClickLocation.GetGridEntityId(EntityManager), out var grid))
+            if (!_mapManager.TryGetGrid(args.ClickLocation.GetGridUid(EntityManager), out var grid))
                 return;
             if (!grid.TryGetTileRef(args.ClickLocation, out var tileRef))
                 return;

Content.Server/Explosion/EntitySystems/ExplosionSystem.Airtight.cs

@@ -100,7 +100,7 @@ public sealed partial class ExplosionSystem : EntitySystem
         if (!EntityManager.TryGetComponent(uid, out TransformComponent? transform) || !transform.Anchored)
             return;
 
-        if (!_mapManager.TryGetGrid(transform.GridEntityId, out var grid))
+        if (!_mapManager.TryGetGrid(transform.GridUid, out var grid))
             return;
 
         UpdateAirtightMap(grid, grid.CoordinatesToTile(transform.Coordinates));

Content.Server/Fluids/EntitySystems/FluidSpreaderSystem.cs

@@ -103,7 +103,7 @@ public sealed class FluidSpreaderSystem : EntitySystem
         var prototypeName = metadataOriginal.EntityPrototype!.ID;
         var visitedTiles = new HashSet<Vector2i>();
 
-        if (!_mapManager.TryGetGrid(transformOrig.GridEntityId, out var mapGrid))
+        if (!_mapManager.TryGetGrid(transformOrig.GridUid, out var mapGrid))
             return;
 
         // skip origin puddle

Content.Server/Fluids/EntitySystems/MoppingSystem.cs

@@ -76,7 +76,7 @@ public sealed class MoppingSystem : EntitySystem
 
     private void ReleaseToFloor(EntityCoordinates clickLocation, AbsorbentComponent absorbent, Solution? absorbedSolution)
     {
-        if ((_mapManager.TryGetGrid(clickLocation.GetGridEntityId(EntityManager), out var mapGrid)) // needs valid grid
+        if ((_mapManager.TryGetGrid(clickLocation.GetGridUid(EntityManager), out var mapGrid)) // needs valid grid
             && absorbedSolution is not null) // needs a solution to place on the tile
         {
             TileRef tile = mapGrid.GetTileRef(clickLocation);

Content.Server/Fluids/EntitySystems/SpillableSystem.cs

@@ -132,7 +132,7 @@ public sealed class SpillableSystem : EntitySystem
         if (solution.TotalVolume == 0) return null;
 
 
-        if (!_mapManager.TryGetGrid(coordinates.GetGridEntityId(EntityManager), out var mapGrid))
+        if (!_mapManager.TryGetGrid(coordinates.GetGridUid(EntityManager), out var mapGrid))
             return null; // Let's not spill to space.
 
         return SpillAt(mapGrid.GetTileRef(coordinates), solution, prototype, overflow, sound,

Content.Server/Fluids/EntitySystems/SpraySystem.cs

@@ -59,7 +59,7 @@ public sealed class SpraySystem : EntitySystem
 
         var playerPos = Transform(args.User).Coordinates;
 
-        if (args.ClickLocation.GetGridEntityId(EntityManager) != playerPos.GetGridEntityId(EntityManager))
+        if (args.ClickLocation.GetGridUid(EntityManager) != playerPos.GetGridUid(EntityManager))
             return;
 
         var direction = (args.ClickLocation.Position - playerPos.Position).Normalized;

Content.Server/Gravity/EntitySystems/GravityGeneratorSystem.cs

@@ -187,12 +187,11 @@ namespace Content.Server.Gravity.EntitySystems
 
         private void UpdateGravityActive(GravityGeneratorComponent grav, bool shake)
         {
-            var gridId = EntityManager.GetComponent<TransformComponent>(grav.Owner).GridEntityId;
+            var gridId = EntityManager.GetComponent<TransformComponent>(grav.Owner).GridUid;
-            if (gridId == EntityUid.Invalid)
+            if (!_mapManager.TryGetGrid(gridId, out var grid))
                 return;
 
-            var grid = _mapManager.GetGrid(gridId);
+            var gravity = EntityManager.GetComponent<GravityComponent>(gridId.Value);
-            var gravity = EntityManager.GetComponent<GravityComponent>(grid.GridEntityId);
 
             if (grav.GravityActive)
                 _gravitySystem.EnableGravity(gravity);
@@ -200,7 +199,7 @@ namespace Content.Server.Gravity.EntitySystems
                 _gravitySystem.DisableGravity(gravity);
 
             if (shake)
-                _gravityShakeSystem.ShakeGrid(gridId, gravity);
+                _gravityShakeSystem.ShakeGrid(gridId.Value, gravity);
         }
 
         private void OnInteractHand(EntityUid uid, GravityGeneratorComponent component, InteractHandEvent args)

Content.Server/Gravity/EntitySystems/GravityShakeSystem.cs

@@ -76,7 +76,7 @@ namespace Content.Server.Gravity.EntitySystems
             foreach (var player in _playerManager.Sessions)
             {
                 if (player.AttachedEntity is not {Valid: true} attached
-                    || EntityManager.GetComponent<TransformComponent>(attached).GridEntityId != gridId
+                    || EntityManager.GetComponent<TransformComponent>(attached).GridUid != gridId
                     || !EntityManager.HasComponent<CameraRecoilComponent>(attached))
                 {
                     continue;

Content.Server/Gravity/EntitySystems/GravitySystem.cs

@@ -16,22 +16,26 @@ namespace Content.Server.Gravity.EntitySystems
         private void HandleGravityInitialize(EntityUid uid, GravityComponent component, ComponentInit args)
         {
             // Incase there's already a generator on the grid we'll just set it now.
-            var gridId = EntityManager.GetComponent<TransformComponent>(component.Owner).GridEntityId;
+            var gridId = Transform(component.Owner).GridUid;
+
+            if (gridId == null)
+                return;
+
             GravityChangedMessage message;
 
             foreach (var generator in EntityManager.EntityQuery<GravityGeneratorComponent>())
             {
-                if (EntityManager.GetComponent<TransformComponent>(generator.Owner).GridEntityId == gridId && generator.GravityActive)
+                if (Transform(generator.Owner).GridUid == gridId && generator.GravityActive)
                 {
                     component.Enabled = true;
-                    message = new GravityChangedMessage(gridId, true);
+                    message = new GravityChangedMessage(gridId.Value, true);
                     RaiseLocalEvent(message);
                     return;
                 }
             }
 
             component.Enabled = false;
-            message = new GravityChangedMessage(gridId, false);
+            message = new GravityChangedMessage(gridId.Value, false);
             RaiseLocalEvent(message);
         }
 
@@ -43,10 +47,13 @@ namespace Content.Server.Gravity.EntitySystems
         public void EnableGravity(GravityComponent comp)
         {
             if (comp.Enabled) return;
-            comp.Enabled = true;
 
-            var gridId = EntityManager.GetComponent<TransformComponent>(comp.Owner).GridEntityId;
+            var gridId = Transform(comp.Owner).GridUid;
-            var message = new GravityChangedMessage(gridId, true);
+            if (gridId == null)
+                return;
+
+            comp.Enabled = true;
+            var message = new GravityChangedMessage(gridId.Value, true);
             RaiseLocalEvent(message);
         }
 
@@ -55,8 +62,11 @@ namespace Content.Server.Gravity.EntitySystems
             if (!comp.Enabled) return;
             comp.Enabled = false;
 
-            var gridId = EntityManager.GetComponent<TransformComponent>(comp.Owner).GridEntityId;
+            var gridId = Transform(comp.Owner).GridUid;
-            var message = new GravityChangedMessage(gridId, false);
+            if (gridId == null)
+                return;
+
+            var message = new GravityChangedMessage(gridId.Value, false);
             RaiseLocalEvent(message);
         }
     }

Content.Server/Gravity/EntitySystems/WeightlessSystem.cs

@@ -34,11 +34,11 @@ namespace Content.Server.Gravity.EntitySystems
         public void AddAlert(AlertsComponent status)
         {
             var xform = Transform(status.Owner);
-            var alerts = _alerts.GetOrNew(xform.GridEntityId);
+            var alerts = _alerts.GetOrNew(xform.GridID);
 
             alerts.Add(status);
 
-            if (_mapManager.TryGetGrid(xform.GridEntityId, out var grid))
+            if (_mapManager.TryGetGrid(xform.GridUid, out var grid))
             {
                 if (EntityManager.GetComponent<GravityComponent>(grid.GridEntityId).Enabled)
                 {
@@ -53,7 +53,7 @@ namespace Content.Server.Gravity.EntitySystems
 
         public void RemoveAlert(AlertsComponent status)
         {
-            var grid = EntityManager.GetComponent<TransformComponent>(status.Owner).GridEntityId;
+            var grid = EntityManager.GetComponent<TransformComponent>(status.Owner).GridID;
             if (!_alerts.TryGetValue(grid, out var statuses))
             {
                 return;
@@ -109,7 +109,10 @@ namespace Content.Server.Gravity.EntitySystems
                 }
             }
 
-            var newGrid = ev.Transform.GridEntityId;
+            if (ev.Transform.MapID == MapId.Nullspace)
+                return;
+
+            var newGrid = ev.Transform.GridID;
             var newStatuses = _alerts.GetOrNew(newGrid);
 
             newStatuses.Add(status);

Content.Server/Interaction/TilePryCommand.cs

@@ -47,9 +47,13 @@ namespace Content.Server.Interaction
             }
 
             var mapManager = IoCManager.Resolve<IMapManager>();
-            var playerGrid = _entities.GetComponent<TransformComponent>(attached).GridEntityId;
+            var xform = _entities.GetComponent<TransformComponent>(attached);
-            var mapGrid = mapManager.GetGrid(playerGrid);
+            var playerGrid = xform.GridUid;
-            var playerPosition = _entities.GetComponent<TransformComponent>(attached).Coordinates;
+
+            if (!mapManager.TryGetGrid(playerGrid, out var mapGrid))
+                return;
+
+            var playerPosition = xform.Coordinates;
             var tileDefinitionManager = IoCManager.Resolve<ITileDefinitionManager>();
 
             for (var i = -radius; i <= radius; i++)

Content.Server/Kudzu/SpreaderSystem.cs

@@ -44,7 +44,7 @@ public sealed class SpreaderSystem : EntitySystem
         if (!EntityManager.TryGetComponent<TransformComponent>(blocker, out var transform))
             return; // how did we get here?
 
-        if (!_mapManager.TryGetGrid(transform.GridEntityId, out var grid)) return;
+        if (!_mapManager.TryGetGrid(transform.GridUid, out var grid)) return;
 
         for (var i = 0; i < Atmospherics.Directions; i++)
         {
@@ -89,7 +89,7 @@ public sealed class SpreaderSystem : EntitySystem
 
         if (spreader.Enabled == false) return false;
 
-        if (!_mapManager.TryGetGrid(transform.GridEntityId, out var grid)) return false;
+        if (!_mapManager.TryGetGrid(transform.GridUid, out var grid)) return false;
 
         var didGrow = false;
 

Content.Server/Medical/CrewMonitoring/CrewMonitoringConsoleSystem.cs

@@ -77,7 +77,7 @@ namespace Content.Server.Medical.CrewMonitoring
             // should work well enough?
             if (TryComp(uid, out IMoverComponent? mover))
                 worldRot = mover.LastGridAngle;
-            else if (_mapManager.TryGetGrid(xform.GridEntityId, out var grid))
+            else if (_mapManager.TryGetGrid(xform.GridUid, out var grid))
                 worldRot = grid.WorldRotation;
 
             // update all sensors info

Content.Server/Mind/MindSystem.cs

@@ -90,7 +90,7 @@ public sealed class MindSystem : EntitySystem
                         return;
 
                     // Async this so that we don't throw if the grid we're on is being deleted.
-                    var gridId = spawnPosition.GetGridEntityId(EntityManager);
+                    var gridId = spawnPosition.GetGridUid(EntityManager);
                     if (!spawnPosition.IsValid(EntityManager) || gridId == EntityUid.Invalid || !_mapManager.GridExists(gridId))
                     {
                         spawnPosition = _gameTicker.GetObserverSpawnPoint();

Content.Server/NodeContainer/EntitySystems/NodeGroupSystem.cs

@@ -286,7 +286,7 @@ namespace Content.Server.NodeContainer.EntitySystems
         private BaseNodeGroup InitGroup(Node node, List<Node> groupNodes)
         {
             var newGroup = (BaseNodeGroup) _nodeGroupFactory.MakeNodeGroup(node.NodeGroupID);
-            newGroup.Initialize(node);
+            newGroup.Initialize(node, EntityManager);
             newGroup.NetId = _groupNetIdCounter++;
 
             var netIdCounter = 0;
@@ -335,7 +335,7 @@ namespace Content.Server.NodeContainer.EntitySystems
         private IEnumerable<Node> GetCompatibleNodes(Node node, EntityQuery<TransformComponent> xformQuery, EntityQuery<NodeContainerComponent> nodeQuery)
         {
             var xform = xformQuery.GetComponent(node.Owner);
-            _mapManager.TryGetGrid(xform.GridEntityId, out var grid);
+            _mapManager.TryGetGrid(xform.GridUid, out var grid);
 
             if (!node.Connectable(EntityManager, xform))
                     yield break;

Content.Server/NodeContainer/NodeGroups/BaseNodeGroup.cs

@@ -1,6 +1,7 @@
 using System.Linq;
 using Content.Server.NodeContainer.Nodes;
 using Robust.Shared.Map;
+using Robust.Shared.Utility;
 
 namespace Content.Server.NodeContainer.NodeGroups
 {
@@ -19,7 +20,7 @@ namespace Content.Server.NodeContainer.NodeGroups
 
         void Create(NodeGroupID groupId);
 
-        void Initialize(Node sourceNode);
+        void Initialize(Node sourceNode, IEntityManager? entMan = null);
 
         void RemoveNode(Node node);
 
@@ -72,10 +73,14 @@ namespace Content.Server.NodeContainer.NodeGroups
             GroupId = groupId;
         }
 
-        public virtual void Initialize(Node sourceNode)
+        public virtual void Initialize(Node sourceNode, IEntityManager? entMan = null)
         {
             // TODO: Can we get rid of this GridId?
-            GridId = IoCManager.Resolve<IEntityManager>().GetComponent<TransformComponent>(sourceNode.Owner).GridEntityId;
+            IoCManager.Resolve(ref entMan);
+
+            var xform = entMan.GetComponent<TransformComponent>(sourceNode.Owner);
+            DebugTools.AssertNotNull(xform.GridUid);
+            GridId = xform.GridUid!.Value;
         }
 
         /// <summary>

Content.Server/NodeContainer/NodeGroups/PipeNet.cs

@@ -24,9 +24,9 @@ namespace Content.Server.NodeContainer.NodeGroups
 
         public EntityUid Grid => GridId;
 
-        public override void Initialize(Node sourceNode)
+        public override void Initialize(Node sourceNode, IEntityManager? entMan = null)
         {
-            base.Initialize(sourceNode);
+            base.Initialize(sourceNode, entMan);
 
             _atmosphereSystem = EntitySystem.Get<AtmosphereSystem>();
             _atmosphereSystem.AddPipeNet(this);

Content.Server/ParticleAccelerator/Components/ParticleAcceleratorControlBoxComponent.cs

@@ -329,7 +329,7 @@ namespace Content.Server.ParticleAccelerator.Components
             // Find fuel chamber first by scanning cardinals.
             if (_entMan.GetComponent<TransformComponent>(Owner).Anchored)
             {
-                var grid = _mapManager.GetGrid(_entMan.GetComponent<TransformComponent>(Owner).GridEntityId);
+                var grid = _mapManager.GetGrid(_entMan.GetComponent<TransformComponent>(Owner).GridUid!.Value);
                 var coords = _entMan.GetComponent<TransformComponent>(Owner).Coordinates;
                 foreach (var maybeFuel in grid.GetCardinalNeighborCells(coords))
                 {
@@ -403,8 +403,14 @@ namespace Content.Server.ParticleAccelerator.Components
         private bool ScanPart<T>(Vector2i offset, [NotNullWhen(true)] out T? part)
             where T : ParticleAcceleratorPartComponent
         {
-            var grid = _mapManager.GetGrid(_entMan.GetComponent<TransformComponent>(Owner).GridEntityId);
+            var xform = _entMan.GetComponent<TransformComponent>(Owner);
-            var coords = _entMan.GetComponent<TransformComponent>(Owner).Coordinates;
+            if (!_mapManager.TryGetGrid(xform.GridUid, out var grid))
+            {
+                part = default;
+                return false;
+            }
+
+            var coords = xform.Coordinates;
             foreach (var ent in grid.GetOffset(coords, offset))
             {
                 if (_entMan.TryGetComponent(ent, out part) && !part.Deleted)

Content.Server/Physics/Controllers/ConveyorController.cs

@@ -104,7 +104,7 @@ namespace Content.Server.Physics.Controllers
 
         public IEnumerable<(EntityUid, TransformComponent)> GetEntitiesToMove(ConveyorComponent comp, TransformComponent xform)
         {
-            if (!_mapManager.TryGetGrid(xform.GridEntityId, out var grid) ||
+            if (!_mapManager.TryGetGrid(xform.GridUid, out var grid) ||
                 !grid.TryGetTileRef(xform.Coordinates, out var tile)) yield break;
 
             var tileAABB = _lookup.GetLocalBounds(tile, grid.TileSize).Enlarged(0.01f);

Content.Server/Physics/Controllers/MoverController.cs

@@ -66,7 +66,7 @@ namespace Content.Server.Physics.Controllers
                 if (pilot.Console == null) continue;
                 _excludedMobs.Add(mover.Owner);
 
-                var gridId = xform.GridEntityId;
+                var gridId = xform.GridUid;
                 // This tries to see if the grid is a shuttle
                 if (!_mapManager.TryGetGrid(gridId, out var grid) ||
                     !EntityManager.TryGetComponent(grid.GridEntityId, out ShuttleComponent? shuttleComponent)) continue;

Content.Server/Power/EntitySystems/CableSystem.Placer.cs

@@ -19,7 +19,7 @@ public sealed partial class CableSystem
 
         if (component.CablePrototypeId == null) return;
 
-        if(!_mapManager.TryGetGrid(args.ClickLocation.GetGridEntityId(EntityManager), out var grid))
+        if(!_mapManager.TryGetGrid(args.ClickLocation.GetGridUid(EntityManager), out var grid))
             return;
 
         var snapPos = grid.TileIndicesFor(args.ClickLocation);

Content.Server/Power/EntitySystems/CableVisSystem.cs

@@ -29,7 +29,7 @@ namespace Content.Server.Power.EntitySystems
                 return;
 
             var transform = Transform(uid);
-            if (!_mapManager.TryGetGrid(transform.GridEntityId, out var grid))
+            if (!_mapManager.TryGetGrid(transform.GridUid, out var grid))
                 return;
 
             var mask = WireVisDirFlags.None;

Content.Server/Power/EntitySystems/ExtensionCableSystem.cs

@@ -48,7 +48,7 @@ namespace Content.Server.Power.EntitySystems
             var xform = Transform(uid);
 
             // If grid deleting no need to update power.
-            if (_mapManager.TryGetGrid(xform.GridEntityId, out var grid))
+            if (_mapManager.TryGetGrid(xform.GridUid, out var grid))
             {
                 if (MetaData(grid.GridEntityId).EntityLifeStage > EntityLifeStage.MapInitialized) return;
             }
@@ -120,7 +120,7 @@ namespace Content.Server.Power.EntitySystems
             var xform = Transform(owner);
             var coordinates = xform.Coordinates;
 
-            if (!_mapManager.TryGetGrid(xform.GridEntityId, out var grid))
+            if (!_mapManager.TryGetGrid(xform.GridUid, out var grid))
                 yield break;
 
             var nearbyEntities = grid.GetCellsInSquareArea(coordinates, (int) Math.Ceiling(range / grid.TileSize));
@@ -238,7 +238,7 @@ namespace Content.Server.Power.EntitySystems
 
         private bool TryFindAvailableProvider(EntityUid owner, float range, [NotNullWhen(true)] out ExtensionCableProviderComponent? foundProvider, TransformComponent? xform = null)
         {
-            if (!Resolve(owner, ref xform) || !_mapManager.TryGetGrid(xform.GridEntityId, out var grid))
+            if (!Resolve(owner, ref xform) || !_mapManager.TryGetGrid(xform.GridUid, out var grid))
             {
                 foundProvider = null;
                 return false;

Content.Server/Power/NodeGroups/ApcNet.cs

@@ -46,9 +46,9 @@ namespace Content.Server.Power.NodeGroups
         [ViewVariables]
         public PowerState.Network NetworkNode { get; } = new();
 
-        public override void Initialize(Node sourceNode)
+        public override void Initialize(Node sourceNode, IEntityManager? entMan = null)
         {
-            base.Initialize(sourceNode);
+            base.Initialize(sourceNode, entMan);
 
             _powerNetSystem.InitApcNet(this);
         }

Content.Server/Power/NodeGroups/PowerNet.cs

@@ -37,9 +37,9 @@ namespace Content.Server.Power.NodeGroups
         [ViewVariables]
         public PowerState.Network NetworkNode { get; } = new();
 
-        public override void Initialize(Node sourceNode)
+        public override void Initialize(Node sourceNode, IEntityManager? entMan = null)
         {
-            base.Initialize(sourceNode);
+            base.Initialize(sourceNode, entMan);
 
             _powerNetSystem.InitPowerNet(this);
         }

Content.Server/Shuttles/Systems/DockingSystem.cs

@@ -67,7 +67,7 @@ namespace Content.Server.Shuttles.Systems
 
             // Assume the docking port itself (and its body) is valid
 
-            if (!_mapManager.TryGetGrid(dockingXform.GridEntityId, out var grid) ||
+            if (!_mapManager.TryGetGrid(dockingXform.GridUid, out var grid) ||
                 !HasComp<ShuttleComponent>(grid.GridEntityId)) return null;
 
             var transform = body.GetTransform();
@@ -93,7 +93,7 @@ namespace Content.Server.Shuttles.Systems
 
             while (enumerator.MoveNext(out var otherGrid))
             {
-                if (otherGrid.GridEntityId == dockingXform.GridEntityId) continue;
+                if (otherGrid.GridEntityId == dockingXform.GridUid) continue;
 
                 foreach (var ent in otherGrid.GetAnchoredEntities(enlargedAABB))
                 {
@@ -164,16 +164,18 @@ namespace Content.Server.Shuttles.Systems
             dockA.DockJoint = null;
             dockA.DockedWith = null;
 
-            // If these grids are ever invalid then need to look at fixing ordering for unanchored events elsewhere.
+            // If these grids are ever null then need to look at fixing ordering for unanchored events elsewhere.
-            var gridAUid = _mapManager.GetGrid(EntityManager.GetComponent<TransformComponent>(dockA.Owner).GridEntityId).GridEntityId;
+            var gridAUid = EntityManager.GetComponent<TransformComponent>(dockA.Owner).GridUid;
-            var gridBUid = _mapManager.GetGrid(EntityManager.GetComponent<TransformComponent>(dockB.Owner).GridEntityId).GridEntityId;
+            var gridBUid = EntityManager.GetComponent<TransformComponent>(dockB.Owner).GridUid;
+            DebugTools.Assert(gridAUid != null);
+            DebugTools.Assert(gridBUid != null);
 
             var msg = new UndockEvent
             {
                 DockA = dockA,
                 DockB = dockB,
-                GridAUid = gridAUid,
+                GridAUid = gridAUid!.Value,
-                GridBUid = gridBUid,
+                GridBUid = gridBUid!.Value,
             };
 
             EntityManager.EventBus.RaiseLocalEvent(dockA.Owner, msg, false);
@@ -305,8 +307,10 @@ namespace Content.Server.Shuttles.Systems
             var dockAXform = EntityManager.GetComponent<TransformComponent>(dockA.Owner);
             var dockBXform = EntityManager.GetComponent<TransformComponent>(dockB.Owner);
 
-            var gridA = _mapManager.GetGrid(dockAXform.GridEntityId).GridEntityId;
+            DebugTools.Assert(dockAXform.GridUid != null);
-            var gridB = _mapManager.GetGrid(dockBXform.GridEntityId).GridEntityId;
+            DebugTools.Assert(dockBXform.GridUid != null);
+            var gridA = dockAXform.GridUid!.Value;
+            var gridB = dockBXform.GridUid!.Value;
 
             SharedJointSystem.LinearStiffness(
                 2f,

Content.Server/Shuttles/Systems/ShuttleConsoleSystem.cs

@@ -142,7 +142,7 @@ namespace Content.Server.Shuttles.Systems
                 pilot.Console is not ShuttleConsoleComponent console) return;
 
             if (!console.SubscribedPilots.Contains(pilot) ||
-                !TryComp<ShuttleComponent>(xform.GridEntityId, out var shuttle)) return;
+                !TryComp<ShuttleComponent>(xform.GridUid, out var shuttle)) return;
 
             SetShuttleMode(args.Mode, console, shuttle);
         }

Content.Server/Shuttles/Systems/SpaceGarbageSystem.cs

@@ -20,7 +20,7 @@ public sealed class SpaceGarbageSystem : EntitySystem
         var ourXform = Transform(args.OurFixture.Body.Owner);
         var otherXform = Transform(args.OtherFixture.Body.Owner);
 
-        if (ourXform.GridEntityId == otherXform.GridEntityId ||
+        if (ourXform.GridUid == otherXform.GridUid ||
             args.OtherFixture.Body.BodyType != BodyType.Static) return;
 
         QueueDel(uid);

Content.Server/Shuttles/Systems/ThrusterSystem.cs

@@ -126,7 +126,7 @@ namespace Content.Server.Shuttles.Systems
 
                         if (new Vector2i((int) direction.X, (int) direction.Y) != new Vector2i(x, y)) continue;
 
-                        DisableThruster(ent.Value, thruster, xform.GridEntityId);
+                        DisableThruster(ent.Value, thruster, xform.GridUid);
                     }
                 }
             }
@@ -147,7 +147,7 @@ namespace Content.Server.Shuttles.Systems
             if (!component.Enabled ||
                 component.Type != ThrusterType.Linear ||
                 !EntityManager.TryGetComponent(uid, out TransformComponent? xform) ||
-                !_mapManager.TryGetGrid(xform.GridEntityId, out var grid) ||
+                !_mapManager.TryGetGrid(xform.GridUid, out var grid) ||
                 !EntityManager.TryGetComponent(grid.GridEntityId, out ShuttleComponent? shuttleComponent))
             {
                 return;
@@ -243,7 +243,7 @@ namespace Content.Server.Shuttles.Systems
         {
             if (component.IsOn ||
                 !Resolve(uid, ref xform) ||
-                !_mapManager.TryGetGrid(xform.GridEntityId, out var grid)) return;
+                !_mapManager.TryGetGrid(xform.GridUid, out var grid)) return;
 
             component.IsOn = true;
 
@@ -304,13 +304,13 @@ namespace Content.Server.Shuttles.Systems
         public void DisableThruster(EntityUid uid, ThrusterComponent component, TransformComponent? xform = null, Angle? angle = null)
         {
             if (!Resolve(uid, ref xform)) return;
-            DisableThruster(uid, component, xform.GridEntityId, xform);
+            DisableThruster(uid, component, xform.GridUid, xform);
         }
 
         /// <summary>
         /// Tries to disable the thruster.
         /// </summary>
-        public void DisableThruster(EntityUid uid, ThrusterComponent component, EntityUid gridId, TransformComponent? xform = null, Angle? angle = null)
+        public void DisableThruster(EntityUid uid, ThrusterComponent component, EntityUid? gridId, TransformComponent? xform = null, Angle? angle = null)
         {
             if (!component.IsOn ||
                 !Resolve(uid, ref xform) ||
@@ -382,8 +382,11 @@ namespace Content.Server.Shuttles.Systems
 
         private bool NozzleExposed(TransformComponent xform)
         {
+            if (xform.GridUid == null)
+                return true;
+
             var (x, y) = xform.LocalPosition + xform.LocalRotation.Opposite().ToWorldVec();
-            var tile = _mapManager.GetGrid(xform.GridEntityId).GetTileRef(new Vector2i((int) Math.Floor(x), (int) Math.Floor(y)));
+            var tile = _mapManager.GetGrid(xform.GridUid.Value).GetTileRef(new Vector2i((int) Math.Floor(x), (int) Math.Floor(y)));
 
             return tile.Tile.IsSpace();
         }

Content.Server/Sound/EmitSoundSystem.cs

@@ -46,7 +46,7 @@ namespace Content.Server.Sound
         private void HandleEmitSoundOnLand(EntityUid eUI, BaseEmitSoundComponent component, LandEvent arg)
         {
             if (!TryComp<TransformComponent>(eUI, out var xform) ||
-                !_mapManager.TryGetGrid(xform.GridEntityId, out var grid)) return;
+                !_mapManager.TryGetGrid(xform.GridUid, out var grid)) return;
 
             var tile = grid.GetTileRef(xform.Coordinates);
 

Content.Server/Station/Systems/StationSystem.cs

@@ -317,13 +317,13 @@ public sealed class StationSystem : EntitySystem
             return CompOrNull<StationMemberComponent>(entity)?.Station;
         }
 
-        if (xform.GridEntityId == EntityUid.Invalid)
+        if (xform.GridUid == EntityUid.Invalid)
         {
             Logger.Debug("A");
             return null;
         }
 
-        return CompOrNull<StationMemberComponent>(xform.GridEntityId)?.Station;
+        return CompOrNull<StationMemberComponent>(xform.GridUid)?.Station;
     }
 }
 

Content.Server/StationEvents/Events/GasLeak.cs

@@ -114,18 +114,18 @@ namespace Content.Server.StationEvents.Events
             if (_timeUntilLeak > 0f) return;
             _timeUntilLeak += LeakCooldown;
 
-            var atmosphereSystem = EntitySystem.Get<AtmosphereSystem>();
+            var atmosphereSystem = _entityManager.EntitySysManager.GetEntitySystem<AtmosphereSystem>();
             
             if (!_foundTile ||
                 _targetGrid == default ||
                 _entityManager.Deleted(_targetGrid) ||
-                !atmosphereSystem.IsSimulatedGrid(_entityManager.GetComponent<TransformComponent>(_targetGrid).GridEntityId))
+                !atmosphereSystem.IsSimulatedGrid(_targetGrid))
             {
                 Running = false;
                 return;
             }
 
-            var environment = atmosphereSystem.GetTileMixture(_entityManager.GetComponent<TransformComponent>(_targetGrid).GridEntityId, _targetTile, true);
+            var environment = atmosphereSystem.GetTileMixture(_targetGrid, _targetTile, true);
 
             environment?.AdjustMoles(_leakGas, LeakCooldown * _molesPerSecond);
         }
@@ -152,14 +152,14 @@ namespace Content.Server.StationEvents.Events
                 if (!_foundTile ||
                     _targetGrid == default ||
                     (!_entityManager.EntityExists(_targetGrid) ? EntityLifeStage.Deleted : _entityManager.GetComponent<MetaDataComponent>(_targetGrid).EntityLifeStage) >= EntityLifeStage.Deleted ||
-                    !atmosphereSystem.IsSimulatedGrid(_entityManager.GetComponent<TransformComponent>(_targetGrid).GridEntityId))
+                    !atmosphereSystem.IsSimulatedGrid(_targetGrid))
                 {
                     return;
                 }
 
                 // Don't want it to be so obnoxious as to instantly murder anyone in the area but enough that
                 // it COULD start potentially start a bigger fire.
-                atmosphereSystem.HotspotExpose(_entityManager.GetComponent<TransformComponent>(_targetGrid).GridID, _targetTile, 700f, 50f, true);
+                atmosphereSystem.HotspotExpose(_targetGrid, _targetTile, 700f, 50f, true);
                 SoundSystem.Play("/Audio/Effects/sparks4.ogg", Filter.Pvs(_targetCoords), _targetCoords);
             }
         }

Content.Server/SubFloor/SubFloorHideSystem.cs

@@ -17,7 +17,7 @@ public sealed class SubFloorHideSystem : SharedSubFloorHideSystem
         // No teleporting entities through floor tiles when anchoring them.
         var xform = Transform(uid);
 
-        if (MapManager.TryGetGrid(xform.GridEntityId, out var grid)
+        if (MapManager.TryGetGrid(xform.GridUid, out var grid)
             && HasFloorCover(grid, grid.TileIndicesFor(xform.Coordinates)))
         {
             args.Cancel();

Content.Server/Tools/ToolSystem.TilePrying.cs

@@ -4,6 +4,7 @@ using Content.Shared.Interaction;
 using Content.Shared.Maps;
 using Content.Shared.Tools.Components;
 using Robust.Shared.Map;
+using Robust.Shared.Utility;
 
 namespace Content.Server.Tools;
 
@@ -26,7 +27,14 @@ public sealed partial class ToolSystem
     private void OnTilePryComplete(EntityUid uid, TilePryingComponent component, TilePryingCompleteEvent args)
     {
         component.CancelToken = null;
-        args.Coordinates.PryTile(EntityManager, _mapManager);
+        var gridUid = args.Coordinates.GetGridUid(EntityManager);
+        if (!_mapManager.TryGetGrid(gridUid, out var grid))
+        {
+            Logger.Error("Attempted to pry from a non-existent grid?");
+            return;
+        }
+
+        grid.GetTileRef(args.Coordinates).PryTile(_mapManager, _tileDefinitionManager, EntityManager);
     }
 
     private void OnTilePryingAfterInteract(EntityUid uid, TilePryingComponent component, AfterInteractEvent args)
@@ -47,7 +55,7 @@ public sealed partial class ToolSystem
         if (!TryComp<ToolComponent?>(component.Owner, out var tool) && component.ToolComponentNeeded)
             return false;
 
-        if (!_mapManager.TryGetGrid(clickLocation.GetGridEntityId(EntityManager), out var mapGrid))
+        if (!_mapManager.TryGetGrid(clickLocation.GetGridUid(EntityManager), out var mapGrid))
             return false;
 
         var tile = mapGrid.GetTileRef(clickLocation);

Content.Shared/Friction/SharedTileFrictionController.cs

@@ -161,7 +161,7 @@ namespace Content.Shared.Friction
 
             // TODO: Make IsWeightless event-based; we already have grid traversals tracked so just raise events
             if (body.Owner.IsWeightless(body, coords, _mapManager) ||
-                !_mapManager.TryGetGrid(xform.GridEntityId, out var grid))
+                !_mapManager.TryGetGrid(xform.GridUid, out var grid))
                 return 0.0f;
 
             if (!coords.IsValid(EntityManager)) return 0.0f;

Content.Shared/Maps/TurfHelpers.cs

@@ -14,9 +14,6 @@ namespace Content.Shared.Maps
         /// </summary>
         public static TileRef GetTileRef(this Vector2i vector2i, EntityUid gridId, IMapManager? mapManager = null)
         {
-            if (!gridId.IsValid())
-                return default;
-
             mapManager ??= IoCManager.Resolve<IMapManager>();
 
             if (!mapManager.TryGetGrid(gridId, out var grid))
@@ -41,7 +38,7 @@ namespace Content.Shared.Maps
 
             mapManager ??= IoCManager.Resolve<IMapManager>();
 
-            if (!mapManager.TryGetGrid(coordinates.GetGridEntityId(entityManager), out var grid))
+            if (!mapManager.TryGetGrid(coordinates.GetGridUid(entityManager), out var grid))
                 return null;
 
 
@@ -89,15 +86,6 @@ namespace Content.Shared.Maps
             return tile.Tile.IsSpace(tileDefinitionManager);
         }
 
-        public static bool PryTile(this EntityCoordinates coordinates, IEntityManager? entityManager = null,
-            IMapManager? mapManager = null)
-        {
-            entityManager ??= IoCManager.Resolve<IEntityManager>();
-            mapManager ??= IoCManager.Resolve<IMapManager>();
-
-            return coordinates.ToVector2i(entityManager, mapManager).PryTile(coordinates.GetGridEntityId(entityManager));
-        }
-
         public static bool PryTile(this Vector2i indices, EntityUid gridId,
             IMapManager? mapManager = null, ITileDefinitionManager? tileDefinitionManager = null, IEntityManager? entityManager = null)
         {

Content.Shared/Movement/Components/MovementIgnoreGravityComponent.cs

@@ -45,9 +45,9 @@ namespace Content.Shared.Movement.Components
                 return ignoreGravityComponent.Weightless;
 
             var transform = entityManager.GetComponent<TransformComponent>(entity);
-            var gridId = transform.GridEntityId;
+            var gridId = transform.GridUid;
 
-            if (!gridId.IsValid())
+            if (gridId == null)
             {
                 // Not on a grid = no gravity for now.
                 // In the future, may want to allow maps to override to always have gravity instead.
@@ -55,7 +55,7 @@ namespace Content.Shared.Movement.Components
             }
 
             mapManager ??= IoCManager.Resolve<IMapManager>();
-            var grid = mapManager.GetGrid(gridId);
+            var grid = mapManager.GetGrid(gridId.Value);
             var invSys = EntitySystem.Get<InventorySystem>();
 
             if (invSys.TryGetSlotEntity(entity, "shoes", out var ent))

Content.Shared/Movement/SharedMoverController.cs

@@ -68,7 +68,7 @@ namespace Content.Shared.Movement
 
         protected Angle GetParentGridAngle(TransformComponent xform, IMoverComponent mover)
         {
-            if (xform.GridEntityId == EntityUid.Invalid || !_mapManager.TryGetGrid(xform.GridEntityId, out var grid))
+            if (!_mapManager.TryGetGrid(xform.GridUid, out var grid))
                 return mover.LastGridAngle;
 
             return grid.WorldRotation;
@@ -90,11 +90,11 @@ namespace Content.Shared.Movement
 
             var worldTotal = _relativeMovement ? parentRotation.RotateVec(total) : total;
 
-            if (transform.GridEntityId != EntityUid.Invalid)
+            if (transform.GridUid != null)
                 mover.LastGridAngle = parentRotation;
 
             if (worldTotal != Vector2.Zero)
-                transform.LocalRotation = transform.GridEntityId != EntityUid.Invalid
+                transform.LocalRotation = transform.GridUid != null
                     ? total.ToWorldAngle()
                     : worldTotal.ToWorldAngle();
 
@@ -130,7 +130,7 @@ namespace Content.Shared.Movement
 
                 if (!touching)
                 {
-                    if (xform.GridEntityId != EntityUid.Invalid)
+                    if (xform.GridUid != EntityUid.Invalid)
                         mover.LastGridAngle = GetParentGridAngle(xform, mover);
 
                     xform.WorldRotation = physicsComponent.LinearVelocity.GetDir().ToAngle();
@@ -152,14 +152,14 @@ namespace Content.Shared.Movement
             if (weightless)
                 worldTotal *= mobMover.WeightlessStrength;
 
-            if (xform.GridEntityId != EntityUid.Invalid)
+            if (xform.GridUid != EntityUid.Invalid)
                 mover.LastGridAngle = parentRotation;
 
             if (worldTotal != Vector2.Zero)
             {
                 // This should have its event run during island solver soooo
                 xform.DeferUpdates = true;
-                xform.LocalRotation = xform.GridEntityId != EntityUid.Invalid
+                xform.LocalRotation = xform.GridUid != EntityUid.Invalid
                     ? total.ToWorldAngle()
                     : worldTotal.ToWorldAngle();
                 xform.DeferUpdates = false;
@@ -229,7 +229,7 @@ namespace Content.Shared.Movement
             if (!CanSound() || !_tags.HasTag(mover.Owner, "FootstepSound")) return false;
 
             var coordinates = xform.Coordinates;
-            var gridId = coordinates.GetGridEntityId(EntityManager);
+            var gridId = coordinates.GetGridUid(EntityManager);
             var distanceNeeded = mover.Sprinting ? StepSoundMoveDistanceRunning : StepSoundMoveDistanceWalking;
 
             // Handle footsteps.
@@ -252,7 +252,7 @@ namespace Content.Shared.Movement
                 return false;
             }
 
-            DebugTools.Assert(gridId != EntityUid.Invalid);
+            DebugTools.Assert(gridId != null);
             mobMover.LastPosition = coordinates;
 
             if (mobMover.StepSoundDistance < distanceNeeded) return false;
@@ -267,7 +267,7 @@ namespace Content.Shared.Movement
                 return true;
             }
 
-            return TryGetFootstepSound(gridId, coordinates, out variation, out sound);
+            return TryGetFootstepSound(gridId!.Value, coordinates, out variation, out sound);
         }
 
         private bool TryGetFootstepSound(EntityUid gridId, EntityCoordinates coordinates, out float variation, [NotNullWhen(true)] out string? sound)

Content.Shared/SubFloor/SharedSubFloorHideSystem.cs

@@ -98,7 +98,7 @@ namespace Content.Shared.SubFloor
             if (!Resolve(uid, ref component, ref xform))
                 return;
 
-            if (xform.Anchored && MapManager.TryGetGrid(xform.GridEntityId, out var grid))
+            if (xform.Anchored && MapManager.TryGetGrid(xform.GridUid, out var grid))
                 component.IsUnderCover = HasFloorCover(grid, grid.TileIndicesFor(xform.Coordinates));
             else
                 component.IsUnderCover = false;

Content.Shared/SubFloor/TrayScannerSystem.cs

@@ -208,7 +208,7 @@ public sealed class TrayScannerSystem : EntitySystem
 
         // For now, limiting to the scanner's own grid. We could do a grid-lookup, but then what do we do if one grid
         // flies away, while the scanner's local-position remains unchanged?
-        if (_mapManager.TryGetGrid(transform.GridEntityId, out var grid))
+        if (_mapManager.TryGetGrid(transform.GridUid, out var grid))
         {
             foreach (var entity in grid.GetAnchoredEntities(worldBox))
             {