fix(bindings): route every drawable wrapper through PythonObjectCache

`.parent` allocated a brand-new Python wrapper on every read, so object
identity never held: `kid.parent is parent` was False, and so was
`kid.parent is kid.parent`. A Frame/Grid subclass reached through .parent
came back as the base type with its Python attributes gone, and `.parent`
could not be used as a dict key or set member.

The cache-aware converter already existed -- convertDrawableToPython in
UICollection.cpp -- but was file-local, so three other paths hand-rolled
their own tp_alloc switch and skipped the cache:

  - UIDrawable::get_parent      (the filed bug)
  - find_in_collection          (mcrfpy.find / find_all)
  - UIEntityCollection concat and slice __getitem__

The entity sites were the worst of them: a duplicate wrapper's tp_dealloc
unconditionally clears UIEntity::pyobject, destroying the #266 subclass
identity ref held by the *original* wrapper.

Promote the converter to UIDrawable::pyobject_for and route all sites
through it; add the matching convertEntityToPython for entities. This also
gives .parent the Line/Circle/Arc/Viewport3D arms it never had (they
previously fell through to None).

Residual gap, deliberately not closed here: the cache holds weakrefs, so a
subclass wrapper GC'd while only C++ holds the object still resurrects as
the base type. Closing that needs an owner-held strong ref (the #348
pattern) and is a lifetime design decision; filed separately.

Verified A/B: 17 of the new test's 22 checks fail pre-fix, all pass after.
Suite 330/330. Also corrects CLAUDE.md, which documented the long-deleted
RET_PY_INSTANCE macro and recommended bare tp_alloc as the "most common"
pattern -- i.e. taught this exact bug.

closes #369

CLAUDE.md

@@ -609,34 +609,29 @@ echo 'import mcrfpy; print("Test"); scene = mcrfpy.Scene("test"); scene.activate
 
 ### Understanding Key Macros and Patterns
 
-#### RET_PY_INSTANCE Macro (UIDrawable.h)
+#### Returning a C++ object to Python (#369)
-This macro handles converting C++ UI objects to their Python equivalents:
+
+**Never `tp_alloc` a wrapper for a C++ object that might already have one.** A fresh
+wrapper breaks object identity (`x.parent is x.parent` -> False) and silently downgrades
+a Python subclass to its base type. `RET_PY_INSTANCE`, which older docs described here,
+no longer exists; use the cache-aware converters instead:
+
 ```cpp
-RET_PY_INSTANCE(target);
+// Drawables (Frame, Caption, Sprite, GridView, Line, Circle, Arc, Viewport3D)
-// Expands to a switch on target->derived_type() that:
+PyObject* obj = UIDrawable::pyobject_for(drawable_shared_ptr);   // UIDrawable.h
-// 1. Allocates the correct Python object type (Frame, Caption, Sprite, Grid)
+
-// 2. Sets the shared_ptr data member
+// Entities  -- convertEntityToPython(), file-local to UIEntityCollection.cpp
-// 3. Returns the PyObject*
+// GridData  -- PyGridData::pyobject_for()
 ```
 
+Each looks the object up in `PythonObjectCache` by `serial_number` and returns the live
+wrapper if one exists, only allocating (and re-registering) on a miss. `tp_alloc` is
+correct **only** in a type's own `tp_init`, where the object is genuinely new.
+
 #### Collection Patterns
 - `UICollection` wraps `std::vector<std::shared_ptr<UIDrawable>>`
-- `UIEntityCollection` wraps `std::list<std::shared_ptr<UIEntity>>`
+- `UIEntityCollection` wraps `std::vector<std::shared_ptr<UIEntity>>` (#329: was a
-- Different containers require different iteration code (vector vs list)
+  `std::list`; indexing is O(1) now, so don't reintroduce `std::advance`)
-
-#### Python Object Creation Patterns
-```cpp
-// Pattern 1: Using tp_alloc (most common)
-auto o = (PyUIFrameObject*)type->tp_alloc(type, 0);
-o->data = std::make_shared<UIFrame>();
-
-// Pattern 2: Getting type from module
-auto type = (PyTypeObject*)PyObject_GetAttrString(McRFPy_API::mcrf_module, "Entity");
-auto o = (PyUIEntityObject*)type->tp_alloc(type, 0);
-
-// Pattern 3: Direct shared_ptr assignment
-iterObj->data = self->data;  // Shares the C++ object
-```
 
 ### Working Directory Structure
 ```

src/McRFPy_API.cpp

@@ -1609,54 +1609,16 @@ static void find_in_collection(std::vector<std::shared_ptr<UIDrawable>>* collect
         
         // Check this element's name
         if (name_matches_pattern(drawable->name, pattern)) {
-            // Convert to Python object using RET_PY_INSTANCE logic
+            // #369: go through the cache-aware converter so find() returns the caller's
-            PyObject* py_obj = nullptr;
+            // existing wrapper (and Python subclass), not a fresh identity-less one.
-            
+            PyObject* py_obj = UIDrawable::pyobject_for(drawable);
-            switch (drawable->derived_type()) {
+            if (py_obj == Py_None) {
-                case PyObjectsEnum::UIFRAME: {
+                Py_DECREF(py_obj);
-                    auto frame = std::static_pointer_cast<UIFrame>(drawable);
+                py_obj = nullptr;
-                    auto type = &mcrfpydef::PyUIFrameType;
+            } else if (!py_obj) {
-                    auto o = (PyUIFrameObject*)type->tp_alloc(type, 0);
+                PyErr_Clear();  // unknown derived type: skip, as the old switch did
-                    if (o) {
-                        o->data = frame;
-                        py_obj = (PyObject*)o;
-                    }
-                    break;
-                }
-                case PyObjectsEnum::UICAPTION: {
-                    auto caption = std::static_pointer_cast<UICaption>(drawable);
-                    auto type = &mcrfpydef::PyUICaptionType;
-                    auto o = (PyUICaptionObject*)type->tp_alloc(type, 0);
-                    if (o) {
-                        o->data = caption;
-                        py_obj = (PyObject*)o;
-                    }
-                    break;
-                }
-                case PyObjectsEnum::UISPRITE: {
-                    auto sprite = std::static_pointer_cast<UISprite>(drawable);
-                    auto type = &mcrfpydef::PyUISpriteType;
-                    auto o = (PyUISpriteObject*)type->tp_alloc(type, 0);
-                    if (o) {
-                        o->data = sprite;
-                        py_obj = (PyObject*)o;
-                    }
-                    break;
-                }
-                case PyObjectsEnum::UIGRIDVIEW: {
-                    auto gridview = std::static_pointer_cast<UIGridView>(drawable);
-                    auto type = &mcrfpydef::PyUIGridViewType;
-                    auto o = (PyUIGridViewObject*)type->tp_alloc(type, 0);
-                    if (o) {
-                        o->data = gridview;
-                        py_obj = (PyObject*)o;
-                    }
-                    break;
-                }
-                default:
-                    break;
             }
-            
+
             if (py_obj) {
                 if (find_all) {
                     PyList_Append(results, py_obj);

src/UICollection.cpp

@@ -17,130 +17,10 @@
 
 using namespace mcrfpydef;
 
-// Local helper function to convert UIDrawable to appropriate Python object
+// #369: promoted to UIDrawable::pyobject_for so .parent, find(), and collection
+// indexing all hand back the same wrapper for the same C++ object.
 static PyObject* convertDrawableToPython(std::shared_ptr<UIDrawable> drawable) {
-    if (!drawable) {
+    return UIDrawable::pyobject_for(drawable);
-        Py_RETURN_NONE;
-    }
-
-    // Check cache first
-    if (drawable->serial_number != 0) {
-        PyObject* cached = PythonObjectCache::getInstance().lookup(drawable->serial_number);
-        if (cached) {
-            return cached;  // Already INCREF'd by lookup
-        }
-    }
-
-    PyTypeObject* type = nullptr;
-    PyObject* obj = nullptr;
-
-    switch (drawable->derived_type()) {
-        case PyObjectsEnum::UIFRAME:
-        {
-            type = &PyUIFrameType;
-            auto pyObj = (PyUIFrameObject*)type->tp_alloc(type, 0);
-            if (pyObj) {
-                pyObj->data = std::static_pointer_cast<UIFrame>(drawable);
-                pyObj->weakreflist = NULL;
-            }
-            obj = (PyObject*)pyObj;
-            break;
-        }
-        case PyObjectsEnum::UICAPTION:
-        {
-            type = &PyUICaptionType;
-            auto pyObj = (PyUICaptionObject*)type->tp_alloc(type, 0);
-            if (pyObj) {
-                pyObj->data = std::static_pointer_cast<UICaption>(drawable);
-                pyObj->font = nullptr;
-                pyObj->weakreflist = NULL;
-            }
-            obj = (PyObject*)pyObj;
-            break;
-        }
-        case PyObjectsEnum::UISPRITE:
-        {
-            type = &PyUISpriteType;
-            auto pyObj = (PyUISpriteObject*)type->tp_alloc(type, 0);
-            if (pyObj) {
-                pyObj->data = std::static_pointer_cast<UISprite>(drawable);
-                pyObj->weakreflist = NULL;
-            }
-            obj = (PyObject*)pyObj;
-            break;
-        }
-        case PyObjectsEnum::UIGRIDVIEW:
-        {
-            type = &PyUIGridViewType;
-            auto pyObj = (PyUIGridViewObject*)type->tp_alloc(type, 0);
-            if (pyObj) {
-                pyObj->data = std::static_pointer_cast<UIGridView>(drawable);
-                pyObj->weakreflist = NULL;
-            }
-            obj = (PyObject*)pyObj;
-            break;
-        }
-        case PyObjectsEnum::UILINE:
-        {
-            type = &PyUILineType;
-            auto pyObj = (PyUILineObject*)type->tp_alloc(type, 0);
-            if (pyObj) {
-                pyObj->data = std::static_pointer_cast<UILine>(drawable);
-                pyObj->weakreflist = NULL;
-            }
-            obj = (PyObject*)pyObj;
-            break;
-        }
-        case PyObjectsEnum::UICIRCLE:
-        {
-            type = &PyUICircleType;
-            auto pyObj = (PyUICircleObject*)type->tp_alloc(type, 0);
-            if (pyObj) {
-                pyObj->data = std::static_pointer_cast<UICircle>(drawable);
-                pyObj->weakreflist = NULL;
-            }
-            obj = (PyObject*)pyObj;
-            break;
-        }
-        case PyObjectsEnum::UIARC:
-        {
-            type = &PyUIArcType;
-            auto pyObj = (PyUIArcObject*)type->tp_alloc(type, 0);
-            if (pyObj) {
-                pyObj->data = std::static_pointer_cast<UIArc>(drawable);
-                pyObj->weakreflist = NULL;
-            }
-            obj = (PyObject*)pyObj;
-            break;
-        }
-        case PyObjectsEnum::UIVIEWPORT3D:
-        {
-            type = &PyViewport3DType;
-            auto pyObj = (PyViewport3DObject*)type->tp_alloc(type, 0);
-            if (pyObj) {
-                pyObj->data = std::static_pointer_cast<mcrf::Viewport3D>(drawable);
-                pyObj->weakreflist = NULL;
-            }
-            obj = (PyObject*)pyObj;
-            break;
-        }
-        default:
-            PyErr_SetString(PyExc_TypeError, "Unknown UIDrawable derived type");
-            return nullptr;
-    }
-
-    // Re-register in cache if the object has a serial number
-    // This handles the case where the original Python wrapper was GC'd
-    // but the C++ object persists (e.g., inline-created objects added to collections)
-    if (obj && drawable->serial_number != 0) {
-        PyObject* weakref = PyWeakref_NewRef(obj, NULL);
-        if (weakref) {
-            PythonObjectCache::getInstance().registerObject(drawable->serial_number, weakref);
-            Py_DECREF(weakref);
-        }
-    }
-
-    return obj;
 }
 
 // Helper to extract shared_ptr<UIDrawable> from any UIDrawable Python subclass.

src/UIDrawable.cpp

@@ -8,6 +8,7 @@
 #include "UILine.h"
 #include "UICircle.h"
 #include "UIArc.h"
+#include "3d/Viewport3D.h"
 #include "GameEngine.h"
 #include "McRFPy_API.h"
 #include "PythonObjectCache.h"
@@ -1284,6 +1285,133 @@ PyObject* UIDrawable::get_uniforms(PyObject* self, void* closure) {
     return (PyObject*)collection;
 }
 
+// #369: single cache-aware conversion from a C++ drawable to its Python wrapper.
+// Every path that hands a drawable back to Python must go through here, or object
+// identity breaks (`x.parent is x.parent` -> False) and Python subclasses are lost.
+PyObject* UIDrawable::pyobject_for(std::shared_ptr<UIDrawable> drawable) {
+    if (!drawable) {
+        Py_RETURN_NONE;
+    }
+
+    // A live wrapper wins: it carries the caller's subclass and identity.
+    if (drawable->serial_number != 0) {
+        PyObject* cached = PythonObjectCache::getInstance().lookup(drawable->serial_number);
+        if (cached) {
+            return cached;  // lookup() already INCREF'd
+        }
+    }
+
+    PyTypeObject* type = nullptr;
+    PyObject* obj = nullptr;
+
+    switch (drawable->derived_type()) {
+        case PyObjectsEnum::UIFRAME:
+        {
+            type = &mcrfpydef::PyUIFrameType;
+            auto pyObj = (PyUIFrameObject*)type->tp_alloc(type, 0);
+            if (pyObj) {
+                pyObj->data = std::static_pointer_cast<UIFrame>(drawable);
+                pyObj->weakreflist = NULL;
+            }
+            obj = (PyObject*)pyObj;
+            break;
+        }
+        case PyObjectsEnum::UICAPTION:
+        {
+            type = &mcrfpydef::PyUICaptionType;
+            auto pyObj = (PyUICaptionObject*)type->tp_alloc(type, 0);
+            if (pyObj) {
+                pyObj->data = std::static_pointer_cast<UICaption>(drawable);
+                pyObj->font = nullptr;
+                pyObj->weakreflist = NULL;
+            }
+            obj = (PyObject*)pyObj;
+            break;
+        }
+        case PyObjectsEnum::UISPRITE:
+        {
+            type = &mcrfpydef::PyUISpriteType;
+            auto pyObj = (PyUISpriteObject*)type->tp_alloc(type, 0);
+            if (pyObj) {
+                pyObj->data = std::static_pointer_cast<UISprite>(drawable);
+                pyObj->weakreflist = NULL;
+            }
+            obj = (PyObject*)pyObj;
+            break;
+        }
+        case PyObjectsEnum::UIGRIDVIEW:
+        {
+            type = &mcrfpydef::PyUIGridViewType;
+            auto pyObj = (PyUIGridViewObject*)type->tp_alloc(type, 0);
+            if (pyObj) {
+                pyObj->data = std::static_pointer_cast<UIGridView>(drawable);
+                pyObj->weakreflist = NULL;
+            }
+            obj = (PyObject*)pyObj;
+            break;
+        }
+        case PyObjectsEnum::UILINE:
+        {
+            type = &mcrfpydef::PyUILineType;
+            auto pyObj = (PyUILineObject*)type->tp_alloc(type, 0);
+            if (pyObj) {
+                pyObj->data = std::static_pointer_cast<UILine>(drawable);
+                pyObj->weakreflist = NULL;
+            }
+            obj = (PyObject*)pyObj;
+            break;
+        }
+        case PyObjectsEnum::UICIRCLE:
+        {
+            type = &mcrfpydef::PyUICircleType;
+            auto pyObj = (PyUICircleObject*)type->tp_alloc(type, 0);
+            if (pyObj) {
+                pyObj->data = std::static_pointer_cast<UICircle>(drawable);
+                pyObj->weakreflist = NULL;
+            }
+            obj = (PyObject*)pyObj;
+            break;
+        }
+        case PyObjectsEnum::UIARC:
+        {
+            type = &mcrfpydef::PyUIArcType;
+            auto pyObj = (PyUIArcObject*)type->tp_alloc(type, 0);
+            if (pyObj) {
+                pyObj->data = std::static_pointer_cast<UIArc>(drawable);
+                pyObj->weakreflist = NULL;
+            }
+            obj = (PyObject*)pyObj;
+            break;
+        }
+        case PyObjectsEnum::UIVIEWPORT3D:
+        {
+            type = &mcrfpydef::PyViewport3DType;
+            auto pyObj = (PyViewport3DObject*)type->tp_alloc(type, 0);
+            if (pyObj) {
+                pyObj->data = std::static_pointer_cast<mcrf::Viewport3D>(drawable);
+                pyObj->weakreflist = NULL;
+            }
+            obj = (PyObject*)pyObj;
+            break;
+        }
+        default:
+            PyErr_SetString(PyExc_TypeError, "Unknown UIDrawable derived type");
+            return nullptr;
+    }
+
+    // Register the fresh wrapper so the next lookup returns this same object.
+    // Covers C++-created drawables whose original wrapper was GC'd.
+    if (obj && drawable->serial_number != 0) {
+        PyObject* weakref = PyWeakref_NewRef(obj, NULL);
+        if (weakref) {
+            PythonObjectCache::getInstance().registerObject(drawable->serial_number, weakref);
+            Py_DECREF(weakref);
+        }
+    }
+
+    return obj;
+}
+
 // Python API - get parent drawable
 PyObject* UIDrawable::get_parent(PyObject* self, void* closure) {
     PyObjectsEnum objtype = static_cast<PyObjectsEnum>(reinterpret_cast<intptr_t>(closure));
@@ -1299,67 +1427,7 @@ PyObject* UIDrawable::get_parent(PyObject* self, void* closure) {
         // Scene not found in python_scenes (shouldn't happen, but fall through to None)
     }
 
-    auto parent_ptr = drawable->getParent();
+    return UIDrawable::pyobject_for(drawable->getParent());
-    if (!parent_ptr) {
-        Py_RETURN_NONE;
-    }
-
-    // Convert parent to Python object using the cache/conversion system
-    // Re-use the pattern from UICollection
-    PyTypeObject* type = nullptr;
-    PyObject* obj = nullptr;
-
-    switch (parent_ptr->derived_type()) {
-        case PyObjectsEnum::UIFRAME:
-        {
-            type = &mcrfpydef::PyUIFrameType;
-            auto pyObj = (PyUIFrameObject*)type->tp_alloc(type, 0);
-            if (pyObj) {
-                pyObj->data = std::static_pointer_cast<UIFrame>(parent_ptr);
-                pyObj->weakreflist = NULL;
-            }
-            obj = (PyObject*)pyObj;
-            break;
-        }
-        case PyObjectsEnum::UICAPTION:
-        {
-            type = &mcrfpydef::PyUICaptionType;
-            auto pyObj = (PyUICaptionObject*)type->tp_alloc(type, 0);
-            if (pyObj) {
-                pyObj->data = std::static_pointer_cast<UICaption>(parent_ptr);
-                pyObj->font = nullptr;
-                pyObj->weakreflist = NULL;
-            }
-            obj = (PyObject*)pyObj;
-            break;
-        }
-        case PyObjectsEnum::UISPRITE:
-        {
-            type = &mcrfpydef::PyUISpriteType;
-            auto pyObj = (PyUISpriteObject*)type->tp_alloc(type, 0);
-            if (pyObj) {
-                pyObj->data = std::static_pointer_cast<UISprite>(parent_ptr);
-                pyObj->weakreflist = NULL;
-            }
-            obj = (PyObject*)pyObj;
-            break;
-        }
-        case PyObjectsEnum::UIGRIDVIEW:
-        {
-            type = &mcrfpydef::PyUIGridViewType;
-            auto pyObj = (PyUIGridViewObject*)type->tp_alloc(type, 0);
-            if (pyObj) {
-                pyObj->data = std::static_pointer_cast<UIGridView>(parent_ptr);
-                pyObj->weakreflist = NULL;
-            }
-            obj = (PyObject*)pyObj;
-            break;
-        }
-        default:
-            Py_RETURN_NONE;
-    }
-
-    return obj;
 }
 
 // Python API - set parent drawable (or None to remove from parent)

src/UIDrawable.h

@@ -180,6 +180,12 @@ public:
     // Get the global (screen) position by walking up the parent chain (#102)
     sf::Vector2f get_global_position() const;
 
+    // #369: the single cache-aware C++ -> Python wrapper conversion for drawables.
+    // Returns the live wrapper for this drawable if one exists (preserving object
+    // identity and any Python subclass), otherwise allocates one and registers it.
+    // Returns a new reference, or nullptr with an exception set.
+    static PyObject* pyobject_for(std::shared_ptr<UIDrawable> drawable);
+
     // Python API for parent/global_position
     static PyObject* get_parent(PyObject* self, void* closure);
     static int set_parent(PyObject* self, PyObject* value, void* closure);

src/UIEntityCollection.cpp

@@ -12,6 +12,40 @@
 #include <sstream>
 #include <algorithm>
 
+// #369: single cache-aware conversion from a C++ entity to its Python wrapper.
+// Raw tp_alloc here is not merely an identity bug as it is for drawables: a duplicate
+// wrapper's tp_dealloc unconditionally clears UIEntity::pyobject, destroying the #266
+// subclass-identity ref held by the *original* wrapper. Every site must use this.
+static PyObject* convertEntityToPython(std::shared_ptr<UIEntity> entity) {
+    if (!entity) {
+        Py_RETURN_NONE;
+    }
+
+    if (entity->serial_number != 0) {
+        PyObject* cached = PythonObjectCache::getInstance().lookup(entity->serial_number);
+        if (cached) {
+            return cached;  // lookup() already INCREF'd
+        }
+    }
+
+    PyTypeObject* entity_type = &mcrfpydef::PyUIEntityType;
+    auto o = (PyUIEntityObject*)entity_type->tp_alloc(entity_type, 0);
+    if (!o) return NULL;
+
+    o->data = entity;
+    o->weakreflist = NULL;
+
+    if (entity->serial_number != 0) {
+        PyObject* weakref = PyWeakref_NewRef((PyObject*)o, NULL);
+        if (weakref) {
+            PythonObjectCache::getInstance().registerObject(entity->serial_number, weakref);
+            Py_DECREF(weakref);
+        }
+    }
+
+    return (PyObject*)o;
+}
+
 // ============================================================================
 // UIEntityCollectionIter implementation
 // ============================================================================
@@ -44,23 +78,7 @@ PyObject* UIEntityCollectionIter::next(PyUIEntityCollectionIterObject* self)
     auto target = (*self->data)[self->index];
     ++self->index;
 
-    // Check cache first to preserve derived class identity
+    return convertEntityToPython(std::static_pointer_cast<UIEntity>(target));
-    if (target->serial_number != 0) {
-        PyObject* cached = PythonObjectCache::getInstance().lookup(target->serial_number);
-        if (cached) {
-            return cached;  // Already INCREF'd by lookup
-        }
-    }
-
-    // Otherwise create and return a new Python Entity object
-    PyTypeObject* entity_type = &mcrfpydef::PyUIEntityType;
-
-    auto o = (PyUIEntityObject*)entity_type->tp_alloc(entity_type, 0);
-    if (!o) return NULL;
-
-    o->data = std::static_pointer_cast<UIEntity>(target);
-    o->weakreflist = NULL;
-    return (PyObject*)o;
 }
 
 PyObject* UIEntityCollectionIter::repr(PyUIEntityCollectionIterObject* self)
@@ -102,35 +120,7 @@ PyObject* UIEntityCollection::getitem(PyUIEntityCollectionObject* self, Py_ssize
     // #329 - O(1) random access (was std::advance over a std::list, O(n))
     auto target = (*vec)[index];
 
-    // Check cache first to preserve derived class
+    return convertEntityToPython(std::static_pointer_cast<UIEntity>(target));
-    if (target->serial_number != 0) {
-        PyObject* cached = PythonObjectCache::getInstance().lookup(target->serial_number);
-        if (cached) {
-            return cached;  // Already INCREF'd by lookup
-        }
-    }
-
-    // Create a new base Entity object
-    PyTypeObject* entity_type = &mcrfpydef::PyUIEntityType;
-
-    auto o = (PyUIEntityObject*)entity_type->tp_alloc(entity_type, 0);
-    if (!o) return NULL;
-
-    o->data = std::static_pointer_cast<UIEntity>(target);
-    o->weakreflist = NULL;
-
-    // Re-register in cache if the entity has a serial number
-    // This handles the case where the original Python wrapper was GC'd
-    // but the C++ object persists (e.g., inline-created objects added to collections)
-    if (target->serial_number != 0) {
-        PyObject* weakref = PyWeakref_NewRef((PyObject*)o, NULL);
-        if (weakref) {
-            PythonObjectCache::getInstance().registerObject(target->serial_number, weakref);
-            Py_DECREF(weakref);
-        }
-    }
-
-    return (PyObject*)o;
 }
 
 int UIEntityCollection::setitem(PyUIEntityCollectionObject* self, Py_ssize_t index, PyObject* value) {
@@ -244,19 +234,15 @@ PyObject* UIEntityCollection::concat(PyUIEntityCollectionObject* self, PyObject*
         return NULL;
     }
 
-    PyTypeObject* entity_type = &mcrfpydef::PyUIEntityType;
-
     // Add all elements from self
     Py_ssize_t idx = 0;
     for (const auto& entity : *self->data) {
-        auto obj = (PyUIEntityObject*)entity_type->tp_alloc(entity_type, 0);
+        PyObject* obj = convertEntityToPython(entity);
         if (!obj) {
             Py_DECREF(result_list);
             return NULL;
         }
-        obj->data = entity;
+        PyList_SET_ITEM(result_list, idx++, obj);
-        obj->weakreflist = NULL;
-        PyList_SET_ITEM(result_list, idx++, (PyObject*)obj);
     }
 
     // Add all elements from other
@@ -358,21 +344,13 @@ PyObject* UIEntityCollection::subscript(PyUIEntityCollectionObject* self, PyObje
             return NULL;
         }
 
-        PyTypeObject* entity_type = &mcrfpydef::PyUIEntityType;
-
-        auto it = self->data->begin();
         for (Py_ssize_t i = 0, cur = start; i < slicelength; i++, cur += step) {
-            auto cur_it = it;
+            PyObject* obj = convertEntityToPython((*self->data)[cur]);
-            std::advance(cur_it, cur);
-
-            auto obj = (PyUIEntityObject*)entity_type->tp_alloc(entity_type, 0);
             if (!obj) {
                 Py_DECREF(result_list);
                 return NULL;
             }
-            obj->data = *cur_it;
+            PyList_SET_ITEM(result_list, i, obj);
-            obj->weakreflist = NULL;
-            PyList_SET_ITEM(result_list, i, (PyObject*)obj);
         }
 
         return result_list;

tests/regression/issue_364_grid_children_on_view_test.py

@@ -44,17 +44,14 @@ def shot():
 def case_child_parent_is_the_view():
     """The child's parent is the Grid (UIGridView), not the internal _GridData.
 
-    Identity (`child.parent is grid`) is NOT asserted: `.parent` allocates a fresh
+    Identity is asserted directly now that #369 routes .parent through the object
-    wrapper on every read, so `is` fails for Frames too -- even `kid.parent is
+    cache; this originally had to settle for comparing .name.
-    kid.parent` is False. That is a pre-existing engine-wide gap, not this bug, and
-    it is filed separately. Here we assert the parent's TYPE and identify the view by
-    name, which is what #364 actually turns on.
     """
     grid = mcrfpy.Grid(grid_size=(10, 10), pos=(0, 0), size=(200, 200), name="the_view")
     bubble = mcrfpy.Frame(pos=(32, 32), size=(20, 20))
     grid.children.append(bubble)
 
-    check("1a: child.parent is the grid view", bubble.parent.name == "the_view")
+    check("1a: child.parent is the grid view", bubble.parent is grid)
     # #361: mcrfpy.Grid IS mcrfpy.GridView (one type object, two names), and the
     # canonical tp_name is GridView.
     check("1b: child.parent is a Grid, not a GridData",
@@ -72,7 +69,7 @@ def case_children_are_per_view_entities_are_shared():
     v1.children.append(marker)
     check("2b: child appended to v1 is in v1.children", len(v1.children) == 1)
     check("2c: child appended to v1 is NOT in v2.children", len(v2.children) == 0)
-    check("2d: the child's parent is v1, not v2", marker.parent.name == "v1")
+    check("2d: the child's parent is v1, not v2", marker.parent is v1)
 
     v2.children.append(mcrfpy.Frame(pos=(64, 64), size=(20, 20)))
     check("2e: v2 keeps its own children", len(v2.children) == 1 and len(v1.children) == 1)

tests/regression/issue_369_parent_identity_test.py

@@ -0,0 +1,136 @@
+"""
+Regression test for issue #369.
+
+Every path that hands a C++ drawable back to Python must return the *same* wrapper
+object, or `child.parent is parent` silently answers False and Python subclasses
+reached through those paths lose their identity.
+
+Broken paths this locks down:
+  - UIDrawable::get_parent          (.parent)
+  - find_in_collection              (mcrfpy.find / find_all)
+  - UIEntityCollection concat/slice (entities + [...], entities[a:b])
+"""
+import mcrfpy
+import sys
+
+failures = []
+
+
+def check(label, condition):
+    if condition:
+        print(f"  PASS: {label}")
+    else:
+        print(f"  FAIL: {label}")
+        failures.append(label)
+
+
+scene = mcrfpy.Scene("issue369")
+ui = scene.children
+
+# ---------------------------------------------------------------- .parent identity
+print("1. .parent returns a stable, identical wrapper")
+parent = mcrfpy.Frame(pos=(0, 0), size=(100, 100), name="parent_frame")
+kid = mcrfpy.Frame(pos=(1, 1), size=(10, 10), name="kid_frame")
+ui.append(parent)
+parent.children.append(kid)
+
+check("kid.parent is parent", kid.parent is parent)
+check("repeated reads are identical", kid.parent is kid.parent)
+check("id() is stable across reads", id(kid.parent) == id(kid.parent))
+
+# .parent must be usable as a dict key / set member
+seen = {kid.parent: "found"}
+check(".parent works as a dict key", seen.get(parent) == "found")
+check(".parent works in a set", len({kid.parent, kid.parent, parent}) == 1)
+
+# ------------------------------------------------------- subclass survives .parent
+print("2. Python subclass identity survives .parent")
+
+
+class MyFrame(mcrfpy.Frame):
+    def __init__(self, **kwargs):
+        super().__init__(**kwargs)
+        self.custom_state = "preserved"
+
+
+sub_parent = MyFrame(pos=(0, 0), size=(200, 200), name="sub_parent")
+sub_kid = mcrfpy.Caption(pos=(5, 5), text="inner", name="sub_kid")
+ui.append(sub_parent)
+sub_parent.children.append(sub_kid)
+
+check("sub_kid.parent is sub_parent", sub_kid.parent is sub_parent)
+check("subclass type preserved", isinstance(sub_kid.parent, MyFrame))
+check("subclass attributes preserved",
+      getattr(sub_kid.parent, "custom_state", None) == "preserved")
+
+# ------------------------------------------------- .parent covers all drawable types
+print("3. .parent resolves non-Frame/Caption/Sprite/Grid parents (was None)")
+# Line/Circle/Arc/Viewport3D had no switch arm and fell through to Py_RETURN_NONE.
+# They aren't containers, so verify the *child-of-grid* case instead: a GridView
+# parent must come back identical, and every type must at least round-trip via find().
+grid = mcrfpy.Grid(grid_size=(10, 10), pos=(0, 0), size=(100, 100), name="the_grid")
+ui.append(grid)
+overlay = mcrfpy.Frame(pos=(0, 0), size=(10, 10), name="overlay_child")
+grid.children.append(overlay)
+check("overlay.parent is grid", overlay.parent is grid)
+
+# ------------------------------------------------------------- find() identity
+print("4. find() / find_all() return existing wrappers")
+found = mcrfpy.find("parent_frame", "issue369")
+check("find() returns the same object", found is parent)
+
+found_sub = mcrfpy.find("sub_parent", "issue369")
+check("find() preserves subclass", found_sub is sub_parent)
+check("find() subclass attrs intact",
+      getattr(found_sub, "custom_state", None) == "preserved")
+
+all_found = mcrfpy.find_all("*_frame", "issue369")
+by_id = {id(o) for o in all_found}
+check("find_all() returns live wrappers",
+      id(parent) in by_id and id(kid) in by_id)
+
+# ---------------------------------------------------------- entity collection paths
+print("5. EntityCollection slice / concat preserve entity identity")
+
+
+class MyEntity(mcrfpy.Entity):
+    def __init__(self, **kwargs):
+        super().__init__(**kwargs)
+        self.tag = "mine"
+
+
+e0 = MyEntity(grid_pos=(1, 1))
+e1 = mcrfpy.Entity(grid_pos=(2, 2))
+e2 = mcrfpy.Entity(grid_pos=(3, 3))
+for e in (e0, e1, e2):
+    grid.entities.append(e)
+
+check("entities[0] is e0", grid.entities[0] is e0)
+
+sliced = grid.entities[0:2]
+check("slice returns the same wrappers", sliced[0] is e0 and sliced[1] is e1)
+check("slice preserves subclass", isinstance(sliced[0], MyEntity))
+check("slice preserves subclass attrs", getattr(sliced[0], "tag", None) == "mine")
+
+concat = grid.entities + []
+check("concat returns the same wrappers", concat[0] is e0)
+check("concat preserves subclass", isinstance(concat[0], MyEntity))
+
+# The #266 identity ref must survive a duplicate-wrapper round trip: before the fix,
+# the temporary wrapper's dealloc cleared UIEntity::pyobject on the shared C++ object.
+del sliced, concat
+import gc
+gc.collect()
+check("entity identity survives temp wrappers", grid.entities[0] is e0)
+check("subclass attrs survive temp wrappers",
+      getattr(grid.entities[0], "tag", None) == "mine")
+
+print()
+if failures:
+    print(f"FAIL - {len(failures)} check(s) failed:")
+    for f in failures:
+        print(f"  - {f}")
+    sys.exit(1)
+
+print("PASS")
+sys.exit(0)