From 2ae3c2ceb794708165644ddc94911d24aad19ffb Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rwgk@google.com>
Date: Thu, 3 Jun 2021 22:12:12 -0700
Subject: [PATCH] Experiment: restoring original smart_holder_type_casters.h
 from smart_holder branch.

---
 .../detail/smart_holder_type_casters.h        | 61 ++-----------------
 1 file changed, 6 insertions(+), 55 deletions(-)

diff --git a/include/pybind11/detail/smart_holder_type_casters.h b/include/pybind11/detail/smart_holder_type_casters.h
index de16cdf36..b61d0a999 100644
--- a/include/pybind11/detail/smart_holder_type_casters.h
+++ b/include/pybind11/detail/smart_holder_type_casters.h
@@ -26,11 +26,6 @@
 #include <typeinfo>
 #include <utility>
 
-#ifdef JUNK
-#    include <iostream>
-inline void to_cout(std::string msg) { std::cout << msg << std::endl; }
-#endif
-
 PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 
 using pybindit::memory::smart_holder;
@@ -275,31 +270,6 @@ struct smart_holder_type_caster_class_hooks : smart_holder_type_caster_base_tag
         return &modified_type_caster_generic_load_impl::local_load;
     }
 
-    using holder_type = pybindit::memory::smart_holder;
-
-#ifdef JUNK
-    template <typename WrappedType>
-    static bool try_initialization_using_shared_from_this(holder_type *, WrappedType *, ...) {
-        return false;
-    }
-#endif
-
-#ifdef JUNK
-    template <typename WrappedType, typename AnyBaseOfWrappedType>
-    static bool try_initialization_using_shared_from_this(
-        holder_type *uninitialized_location,
-        WrappedType *value_ptr_w_t,
-        const std::enable_shared_from_this<AnyBaseOfWrappedType> *) {
-        auto shd_ptr = std::dynamic_pointer_cast<WrappedType>(
-            detail::try_get_shared_from_this(value_ptr_w_t));
-        if (!shd_ptr)
-            return false;
-        // Note: inst->owned ignored.
-        new (uninitialized_location) holder_type(holder_type::from_shared_ptr(shd_ptr));
-        return true;
-    }
-#endif
-
     template <typename WrappedType, typename AliasType>
     static void init_instance_for_type(detail::instance *inst, const void *holder_const_void_ptr) {
         // Need for const_cast is a consequence of the type_info::init_instance type:
@@ -311,27 +281,17 @@ struct smart_holder_type_caster_class_hooks : smart_holder_type_caster_base_tag
             register_instance(inst, v_h.value_ptr(), v_h.type);
             v_h.set_instance_registered();
         }
+        using holder_type = pybindit::memory::smart_holder;
         if (holder_void_ptr) {
             // Note: inst->owned ignored.
             auto holder_ptr = static_cast<holder_type *>(holder_void_ptr);
             new (std::addressof(v_h.holder<holder_type>())) holder_type(std::move(*holder_ptr));
+        } else if (inst->owned) {
+            new (std::addressof(v_h.holder<holder_type>())) holder_type(
+                holder_type::from_raw_ptr_take_ownership(v_h.value_ptr<WrappedType>()));
         } else {
-#ifdef JUNK
-            if (!try_initialization_using_shared_from_this(
-                    std::addressof(v_h.holder<holder_type>()),
-                    v_h.value_ptr<WrappedType>(),
-                    v_h.value_ptr<WrappedType>())) {
-#endif
-                if (inst->owned) {
-                    new (std::addressof(v_h.holder<holder_type>())) holder_type(
-                        holder_type::from_raw_ptr_take_ownership(v_h.value_ptr<WrappedType>()));
-                } else {
-                    new (std::addressof(v_h.holder<holder_type>())) holder_type(
-                        holder_type::from_raw_ptr_unowned(v_h.value_ptr<WrappedType>()));
-                }
-#ifdef JUNK
-            }
-#endif
+            new (std::addressof(v_h.holder<holder_type>()))
+                holder_type(holder_type::from_raw_ptr_unowned(v_h.value_ptr<WrappedType>()));
         }
         v_h.holder<holder_type>().pointee_depends_on_holder_owner
             = dynamic_raw_ptr_cast_if_possible<AliasType>(v_h.value_ptr<WrappedType>()) != nullptr;
@@ -404,20 +364,11 @@ struct smart_holder_type_caster_load {
         auto type_raw_ptr = convert_type(void_raw_ptr);
         if (holder().pointee_depends_on_holder_owner) {
             // Tie lifetime of trampoline Python part to C++ part (PR #2839).
-#ifdef JUNK
-            to_cout("");
-            to_cout("LOOOK " + std::to_string(__LINE__) + " " + __FILE__);
-#endif
             return std::shared_ptr<T>(
                 type_raw_ptr,
                 shared_ptr_dec_ref_deleter{
                     handle((PyObject *) load_impl.loaded_v_h.inst).inc_ref()});
         }
-#ifdef JUNK
-        if (holder().vptr_is_using_noop_deleter) {
-            throw std::runtime_error("Non-owning holder (loaded_as_shared_ptr).");
-        }
-#endif
         std::shared_ptr<void> void_shd_ptr = holder().template as_shared_ptr<void>();
         return std::shared_ptr<T>(void_shd_ptr, type_raw_ptr);
     }