fix(physics): crash when deleting parts due to misusing simulationTicket iterator

Author: m-doescode

core/src/objects/part.cpp

@@ -54,7 +54,7 @@ void Part::OnWorkspaceAdded(std::optional<std::shared_ptr<Workspace>> oldWorkspa
 }
 
 void Part::OnWorkspaceRemoved(std::shared_ptr<Workspace> oldWorkspace) {
-    if (simulationTicket->get() != nullptr)
+    if (simulationTicket.has_value())
         oldWorkspace->RemoveBody(shared<Part>());
 }
 

core/src/objects/part.h

@@ -109,7 +109,7 @@ class DEF_INST_(explorer_icon="part") Part : public PVInstance {
     DEF_SIGNAL SignalSource TouchEnded;
 
     rp::RigidBody* rigidBody = nullptr;
-    SimulationTicket simulationTicket;
+    std::optional<SimulationTicket> simulationTicket;
     bool rigidBodyDirty = true;
 
     inline SurfaceType GetSurfaceFromFace(NormalId face) { return surfaceFromFace(face); }

core/src/objects/service/workspace.cpp

@@ -165,9 +165,9 @@ void Workspace::PhysicsStep(float deltaTime) {
         if (item.action == QueueItem::QUEUEITEM_ADD) {
             simulatedBodies.push_back(item.part);
             item.part->simulationTicket = --simulatedBodies.end();
-        } else if (item.part->simulationTicket->get() != nullptr) {
-            simulatedBodies.erase(item.part->simulationTicket);
-            item.part->simulationTicket = {};
+        } else if (item.part->simulationTicket.has_value()) {
+            simulatedBodies.erase(item.part->simulationTicket.value());
+            item.part->simulationTicket = std::nullopt;
         }
     }
     queueLock.unlock();