From 211e667351a641c8cf2f60197f311acd70b2a434 Mon Sep 17 00:00:00 2001
From: maelstrom <maelstrom@maelstrom.dev>
Date: Sat, 1 Feb 2025 14:18:53 +0100
Subject: [PATCH] fix: objects being parented to themselves/descendents of
 themselves

---
 src/objects/base/instance.cpp | 15 ++++++++++++++-
 src/objects/base/instance.h   |  4 +++-
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/objects/base/instance.cpp b/src/objects/base/instance.cpp
index 3889262..d17be0f 100644
--- a/src/objects/base/instance.cpp
+++ b/src/objects/base/instance.cpp
@@ -38,7 +38,19 @@ Instance::Instance(InstanceType* type) {
 Instance::~Instance () {
 }
 
-void Instance::SetParent(std::optional<std::shared_ptr<Instance>> newParent) {
+// TODO: Test this
+bool Instance::ancestryContinuityCheck(std::optional<std::shared_ptr<Instance>> newParent) {
+    for (std::optional<std::shared_ptr<Instance>> currentParent = newParent; currentParent.has_value(); currentParent = currentParent.value()->GetParent()) {
+        if (currentParent.value() == this->shared_from_this())
+            return false;
+    }
+    return true;
+}
+
+bool Instance::SetParent(std::optional<std::shared_ptr<Instance>> newParent) {
+    if (!ancestryContinuityCheck(newParent))
+        return false;
+
     auto lastParent = GetParent();
     if (hierarchyPreUpdateHandler.has_value()) hierarchyPreUpdateHandler.value()(this->shared_from_this(), lastParent, newParent);
     // If we currently have a parent, remove ourselves from it before adding ourselves to the new one
@@ -56,6 +68,7 @@ void Instance::SetParent(std::optional<std::shared_ptr<Instance>> newParent) {
     if (hierarchyPostUpdateHandler.has_value()) hierarchyPostUpdateHandler.value()(this->shared_from_this(), lastParent, newParent);
 
     this->OnParentUpdated(lastParent, newParent);
+    return true;
 }
 
 std::optional<std::shared_ptr<Instance>> Instance::GetParent() {
diff --git a/src/objects/base/instance.h b/src/objects/base/instance.h
index d39b146..e85aded 100644
--- a/src/objects/base/instance.h
+++ b/src/objects/base/instance.h
@@ -35,6 +35,8 @@ private:
     std::vector<std::shared_ptr<Instance>> children;
 
     std::optional<std::vector<std::string>> cachedMemberList;
+
+    bool ancestryContinuityCheck(std::optional<std::shared_ptr<Instance>> newParent);
 protected:
     std::unique_ptr<MemberMap> memberMap;
 
@@ -48,7 +50,7 @@ public:
 
     // Instance is abstract, so it should not implement GetClass directly
     virtual InstanceType* GetClass() = 0;
-    void SetParent(std::optional<std::shared_ptr<Instance>> newParent);
+    bool SetParent(std::optional<std::shared_ptr<Instance>> newParent);
     std::optional<std::shared_ptr<Instance>> GetParent();
     inline const std::vector<std::shared_ptr<Instance>> GetChildren() { return children; }