so like theoretically

Author: wonderfulnewworld

Content.Client/Atmos/EntitySystems/AtmosPipeAppearanceSystem.cs

@@ -1,3 +1,4 @@
+using System.Linq;
 using Content.Client.SubFloor;
 using Content.Shared.Atmos;
 using Content.Shared.Atmos.Components;
@@ -30,7 +31,11 @@ private void OnInit(EntityUid uid, PipeAppearanceComponent component, ComponentI
         var numberOfPipeLayers = GetNumberOfPipeLayers(uid, out _);
 
         // Starlight START
-        _sprite.LayerMapTryGet((uid, sprite), PipeVisualLayers.Pipe, out var pipeIndex, false);
+        // Prefer inserting the generated connections directly after the main pipe layer. If a prototype does not
+        // have one, fall back to appending them like LayerMapReserve would instead of using an invalid layer index.
+        var insertionIndex = sprite.AllLayers.Count();
+        if (_sprite.LayerMapTryGet((uid, sprite), PipeVisualLayers.Pipe, out var pipeIndex, false))
+            insertionIndex = pipeIndex + 1;
         // Starlight END
 
         foreach (var layerKey in Enum.GetValues<PipeConnectionLayer>())
@@ -40,10 +45,10 @@ private void OnInit(EntityUid uid, PipeAppearanceComponent component, ComponentI
                 var layerName = layerKey.ToString() + i.ToString();
 
                 // Starlight START
-                // The generated layer should go directly after the main pipe layer, not at the end, hence the pipeIndex+1.
+                // The generated layer should go directly after the main pipe layer when it exists, not at the end.
                 if (!_sprite.LayerMapTryGet((uid, sprite), layerName, out var layer, false))
                 {
-                    layer = pipeIndex + 1;
+                    layer = insertionIndex;
                     _sprite.AddBlankLayer((uid, sprite), layer);
                     _sprite.LayerMapSet((uid, sprite), layerName, layer);
                 }

Resources/Prototypes/Entities/Structures/Piping/Atmospherics/unary.yml

@@ -222,6 +222,10 @@
   placement:
     mode: AlignAtmosPipeLayers # starlight
   components:
+    # Starlight start
+    - type: SandboxCopyOverride
+      override: GasOutletInjector
+    # Starlight end
     - type: Sprite
       drawdepth: FloorObjects
       sprite: _Carpmosia/Structures/Piping/Atmospherics/outletinjector.rsi # Carpmosia-edit - 5 pipe layers
@@ -491,6 +495,10 @@
   placement:
     mode: SnapgridCenter
   components:
+  # Starlight start
+  - type: SandboxCopyOverride
+    override: BaseGasCondenser
+  # Starlight end
   - type: Sprite
     sprite: Structures/Piping/Atmospherics/condenser.rsi
     snapCardinals: true

Resources/Prototypes/_Starlight/Partials/Entities/Structures/Piping/Atmospherics/unary.yml

@@ -4,17 +4,15 @@
     - GasVentPump
     - GasPassiveVent
     - GasVentScrubber
-    - GasOutletInjector
+    # GasOutletInjector and BaseGasCondenser define this component inline instead.
+    # Adding it through a partial would replace their first component, Sprite, due to index-based sequence merging.
     - GasThermoMachineFreezer
     - GasThermoMachineFreezerEnabled
     - GasThermoMachineHeater
     - GasThermoMachineHeaterEnabled
     - GasThermoMachineHellfireFreezer
     - GasThermoMachineHellfireHeater
-    - BaseGasCondenser
   components:
     - type: SandboxCopyOverride
       override: !type:CreateVariants
         values: *protos
-
-