From 4dc5f7f75ca02391a1c246ee426022dfdae8c770 Mon Sep 17 00:00:00 2001
From: Weaselbot <weaselbot@weaselab.dev>
Date: Sun, 21 Jun 2026 20:43:44 -0400
Subject: [PATCH] Fix self-move-assignment and leak in ConflictSet
 move-assignment

The user-declared move-assignment operator overwrote `impl` without first
destroying the existing implementation object, leaking all memory and resources
owned by the left-hand side. Self-move-assignment also set `impl` to nullptr,
leaving the object invalid and leaking the old state.

Fix all three implementations (ConflictSet.cpp, SkipList.cpp, HashTable.cpp)
to guard against self-assignment and to destroy/free the old `impl` before
taking ownership of `other.impl`.
---
 ConflictSet.cpp | 7 ++++++-
 HashTable.cpp   | 8 +++++++-
 SkipList.cpp    | 7 ++++++-
 3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index 26d173d..bba8490 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -5589,7 +5589,12 @@ ConflictSet::ConflictSet(ConflictSet &&other) noexcept
     : impl(std::exchange(other.impl, nullptr)) {}
 
 ConflictSet &ConflictSet::operator=(ConflictSet &&other) noexcept {
-  impl = std::exchange(other.impl, nullptr);
+  if (this != &other) {
+    if (impl) {
+      internal_destroy(impl);
+    }
+    impl = std::exchange(other.impl, nullptr);
+  }
   return *this;
 }
 
diff --git a/HashTable.cpp b/HashTable.cpp
index e3fa477..f76e8c2 100644
--- a/HashTable.cpp
+++ b/HashTable.cpp
@@ -119,7 +119,13 @@ ConflictSet::ConflictSet(ConflictSet &&other) noexcept
     : impl(std::exchange(other.impl, nullptr)) {}
 
 ConflictSet &ConflictSet::operator=(ConflictSet &&other) noexcept {
-  impl = std::exchange(other.impl, nullptr);
+  if (this != &other) {
+    if (impl) {
+      impl->~Impl();
+      safe_free(impl, sizeof(Impl));
+    }
+    impl = std::exchange(other.impl, nullptr);
+  }
   return *this;
 }
 
diff --git a/SkipList.cpp b/SkipList.cpp
index fe09147..7cd7a1e 100644
--- a/SkipList.cpp
+++ b/SkipList.cpp
@@ -981,7 +981,12 @@ ConflictSet::ConflictSet(ConflictSet &&other) noexcept
     : impl(std::exchange(other.impl, nullptr)) {}
 
 ConflictSet &ConflictSet::operator=(ConflictSet &&other) noexcept {
-  impl = std::exchange(other.impl, nullptr);
+  if (this != &other) {
+    if (impl) {
+      internal_destroy(impl);
+    }
+    impl = std::exchange(other.impl, nullptr);
+  }
   return *this;
 }