From a90e7585b96e6e9b29e79aed7a78c0eed7840152 Mon Sep 17 00:00:00 2001
From: Pieter-Jan Briers <pieterjan.briers+git@gmail.com>
Date: Tue, 18 Jul 2023 22:55:18 +0200
Subject: [PATCH] More PA fixes (#18131)

If the PA Control Box isn't rotated to match the Fuel Chamber, it actually rotates itself to match.

This rotation triggered a rotation event, which in turn caused RescanParts() to run again, re-entrantly. This broke everything.

Fixed by adding a boolean to just guard against this.
---
 .../ParticleAcceleratorControlBoxComponent.cs          |  6 ++++++
 .../EntitySystems/ParticleAcceleratorSystem.Parts.cs   | 10 ++++++++++
 2 files changed, 16 insertions(+)

diff --git a/Content.Server/ParticleAccelerator/Components/ParticleAcceleratorControlBoxComponent.cs b/Content.Server/ParticleAccelerator/Components/ParticleAcceleratorControlBoxComponent.cs
index a48d7576e2..035c6ead72 100644
--- a/Content.Server/ParticleAccelerator/Components/ParticleAcceleratorControlBoxComponent.cs
+++ b/Content.Server/ParticleAccelerator/Components/ParticleAcceleratorControlBoxComponent.cs
@@ -39,6 +39,12 @@ public sealed class ParticleAcceleratorControlBoxComponent : Component
     [ViewVariables]
     public bool Firing = false;
 
+    /// <summary>
+    /// Block re-entrant rescanning.
+    /// </summary>
+    [ViewVariables(VVAccess.ReadWrite)]
+    public bool CurrentlyRescanning = false;
+
     /// <summary>
     /// Whether the PA is currently firing or charging to fire.
     /// Bounded by <see cref="ParticleAcceleratorPowerState.Standby"/> and <see cref="MaxStrength"/>.
diff --git a/Content.Server/ParticleAccelerator/EntitySystems/ParticleAcceleratorSystem.Parts.cs b/Content.Server/ParticleAccelerator/EntitySystems/ParticleAcceleratorSystem.Parts.cs
index fc8272185d..860fbdcefe 100644
--- a/Content.Server/ParticleAccelerator/EntitySystems/ParticleAcceleratorSystem.Parts.cs
+++ b/Content.Server/ParticleAccelerator/EntitySystems/ParticleAcceleratorSystem.Parts.cs
@@ -23,6 +23,9 @@ public sealed partial class ParticleAcceleratorSystem
         if (!Resolve(uid, ref controller))
             return;
 
+        if (controller.CurrentlyRescanning)
+            return;
+
         SwitchOff(uid, user, controller);
 
         var partQuery = GetEntityQuery<ParticleAcceleratorPartComponent>();
@@ -67,6 +70,11 @@ public sealed partial class ParticleAcceleratorSystem
             return;
         }
 
+        // When we call SetLocalRotation down there to rotate the control box,
+        // that ends up re-entrantly calling RescanParts() through the move event.
+        // You'll have to take my word for it that that breaks everything, yeah?
+        controller.CurrentlyRescanning = true;
+
         // Align ourselves to match fuel chamber orientation.
         // This means that if you mess up the orientation of the control box it's not a big deal,
         // because the sprite is far from obvious about the orientation.
@@ -112,6 +120,8 @@ public sealed partial class ParticleAcceleratorSystem
                 partState.Master = uid;
         }
 
+        controller.CurrentlyRescanning = false;
+
         UpdatePowerDraw(uid, controller);
         UpdateUI(uid, controller);
     }