Replaces some pybind11::handle uses by type deduction.

This change is done to prevent slicing `pybind11::object` values (or its
subclasses) into `pybind11::handle`, which may result into handles to
garbage collected objects.

Author: nyibbang

src/pyobject.cpp

@@ -333,7 +333,7 @@ Object toObject(const ::py::object& obj)
                                              : ObjectThreadingModel_SingleThread);
 
   const auto attrKeys = ::py::reinterpret_steal<::py::list>(PyObject_Dir(obj.ptr()));
-  for (const ::py::handle& pyAttrKey : attrKeys)
+  for (const auto& pyAttrKey : attrKeys)
   {
     QI_ASSERT_TRUE(pyAttrKey);
     QI_ASSERT_FALSE(pyAttrKey.is_none());
@@ -342,7 +342,7 @@ Object toObject(const ::py::object& obj)
     const auto attrKey = pyAttrKey.cast<std::string>();
     auto memberName = attrKey;
 
-    const ::py::object attr = obj.attr(pyAttrKey);
+    const auto attr = obj.attr(pyAttrKey);
     if (attr.is_none())
     {
       qiLogVerbose() << "The object attribute '" << attrKey

src/pystrand.cpp

@@ -35,15 +35,15 @@ bool isUnboundMethod(const ::py::function& func, const ::py::object& object)
 
   GILAcquire lock;
   const auto dir = ::py::reinterpret_steal<::py::list>(PyObject_Dir(object.ptr()));
-  for (const ::py::handle attrName : dir)
+  for (const auto& attrName : dir)
   {
-    const ::py::handle attr = object.attr(attrName);
+    const auto attr = object.attr(attrName);
     QI_ASSERT_TRUE(attr);
 
     if (!PyMethod_Check(attr.ptr()))
       continue;
 
-    const ::py::handle unboundMethod = PyMethod_GET_FUNCTION(attr.ptr());
+    const auto unboundMethod = ::py::reinterpret_borrow<::py::object>(PyMethod_GET_FUNCTION(attr.ptr()));
     if (func.is(unboundMethod))
       return true;
   }