From 7e3e8672cdd19b19532de216e3df6fc3bae8ed7a Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Thu, 23 Jul 2026 16:50:12 +0200
Subject: kstd: fix some shared_ptr bugs

---
 libs/kstd/kstd/bits/shared_ptr.hpp | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

(limited to 'libs')

diff --git a/libs/kstd/kstd/bits/shared_ptr.hpp b/libs/kstd/kstd/bits/shared_ptr.hpp
index 0d5e0285..7241487f 100644
--- a/libs/kstd/kstd/bits/shared_ptr.hpp
+++ b/libs/kstd/kstd/bits/shared_ptr.hpp
@@ -126,18 +126,18 @@ namespace kstd
       explicit make_shared_control_block(Args &&... args)
           : shared_ptr_control_block_base{1, 1}
       {
-        std::construct_at(std::bit_cast<ObjectType *>(m_storage.data()), std::forward<Args>(args)...);
+        std::construct_at(reinterpret_cast<ObjectType *>(m_storage.data()), std::forward<Args>(args)...);
       }
 
       [[nodiscard]] auto get_pointer() noexcept -> ObjectType *
       {
-        return std::bit_cast<ObjectType *>(m_storage.data());
+        return std::launder(reinterpret_cast<ObjectType *>(m_storage.data()));
       }
 
     protected:
       constexpr auto destroy_object() -> void override
       {
-        std::destroy_at(std::bit_cast<ObjectType *>(m_storage.data()));
+        std::destroy_at(get_pointer());
       }
 
     private:
@@ -229,7 +229,7 @@ namespace kstd
     //! Construct a weak pointer which shares ownership of the object managed by other.
     template<typename Y>
       requires bits::is_shared_pointer_ctor_compatible<Y *, T *>::value
-    constexpr weak_ptr(weak_ptr<Y> const & other)
+    constexpr weak_ptr(weak_ptr<Y> const & other) noexcept
         : m_pointer(other.m_pointer)
         , m_control_block(other.m_control_block)
     {
@@ -242,7 +242,7 @@ namespace kstd
     //! Construct a weak pointer which shares ownership of the object managed by other.
     template<typename Y>
       requires bits::is_shared_pointer_ctor_compatible<Y *, T *>::value
-    constexpr weak_ptr(shared_ptr<Y> const & other)
+    constexpr weak_ptr(shared_ptr<Y> const & other) noexcept
         : m_pointer(other.m_pointer)
         , m_control_block(other.m_control_block)
     {
@@ -418,7 +418,10 @@ namespace kstd
 
     enable_shared_from_this(enable_shared_from_this const &) {}
 
-    auto operator=(enable_shared_from_this const &) -> enable_shared_from_this & {}
+    auto operator=(enable_shared_from_this const &) -> enable_shared_from_this &
+    {
+      return *this;
+    }
 
     ~enable_shared_from_this() = default;
 
@@ -542,7 +545,7 @@ namespace kstd
      *
      * @param other The shared_ptr to copy from.
      */
-    shared_ptr(shared_ptr const & other)
+    shared_ptr(shared_ptr const & other) noexcept
         : m_pointer(other.m_pointer)
         , m_control_block(other.m_control_block)
     {
@@ -560,7 +563,7 @@ namespace kstd
      */
     template<typename U>
       requires(std::is_convertible_v<U *, T *>)
-    shared_ptr(shared_ptr<U> const & other)
+    shared_ptr(shared_ptr<U> const & other) noexcept
         : m_pointer(other.m_pointer)
         , m_control_block(other.m_control_block)
     {
@@ -732,7 +735,9 @@ namespace kstd
      *
      * @return Returns the object owned by *this, equivalent to *get().
      */
-    [[nodiscard]] auto operator*() const -> T &
+    template<typename U = T>
+      requires(!std::is_void_v<std::remove_cv<U>>)
+    [[nodiscard]] auto operator*() const -> U &
     {
       return *m_pointer;
     }
@@ -841,11 +846,10 @@ namespace kstd
   };
 
   /**
-   * @brief Specializes the std::swap algorithm for stl::unique_ptr. Swaps the contents of lhs and rhs. Calls
-   * lhs.swap(rhs).
+   * Swap the contents of lhs and rhs.
    *
    * @tparam T Type of the managed object.
-   * @param lhs, rhs Smart pointers whose contents to swap.
+   * @param lhs, rhs Shared pointers whose contents to swap.
    */
   template<typename T>
   auto swap(shared_ptr<T> & lhs, shared_ptr<T> & rhs) -> void
-- 
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