Call __init__ in initialize method for subclasses

lib/pycall/pyobject_wrapper.rb

@@ -26,6 +26,10 @@ def self.extend_object(obj)
       :|  => :__or__
     }.freeze
 
+    def initialize(*args)
+      __init__(*args)
+    end
+
     def method_missing(name, *args)
       name_str = name.to_s if name.kind_of?(Symbol)
       name_str.chop! if name_str.end_with?('=')

lib/pycall/pytypeobject_wrapper.rb

@@ -20,12 +20,14 @@ def inherited(subclass)
       subclass.instance_variable_set(:@__pyptr__, __pyptr__)
     end
 
-    def new(*args)
-      wrap_pyptr(LibPython::Helpers.call_object(__pyptr__, *args))
+    def new(*args, &b)
+      wrap_pyptr(__new__(__pyptr__, *args)).tap do |obj|
+        obj.instance_eval { initialize(*args, &b) }
+      end
     end
 
     def wrap_pyptr(pyptr)
-      return pyptr if pyptr.kind_of? self
+      return pyptr if pyptr.class <= self
       pyptr = pyptr.__pyptr__ if pyptr.kind_of? PyObjectWrapper
       unless pyptr.kind_of? PyPtr
         raise TypeError, "unexpected argument type #{pyptr.class} (expected PyCall::PyPtr)"

spec/pycall/pytypeobject_wrapper_spec.rb

@@ -239,6 +239,20 @@ module PyCall
         obj = extended_class.new
         expect(obj.__pyptr__.__ob_type__).to eq(simple_class_wrapper)
       end
+
+      it 'calls __init__ only once' do
+        test_class = PyCall.import_module('pycall.initialize_test').InitializeTest
+        obj = test_class.new(42)
+        expect(obj.values.to_a).to eq([42])
+      end
+
+      context 'when __new__ is redefined' do
+        it 'calls __init__ only once' do
+          test_class = PyCall.import_module('pycall.initialize_test').NewOverrideTest
+          obj = test_class.new(42)
+          expect(obj.values.to_a).to eq([42, 42])
+        end
+      end
     end
   end
 end

spec/pycall/subclass_spec.rb

@@ -13,6 +13,10 @@
     Class.new(superclass_wrapper)
   end
 
+  it 'is an instance of subclass' do
+    expect(subclass.new.class).to eq(subclass)
+  end
+
   it 'calls __init__ of superclass' do
     a = subclass.new(1, 2, 3)
     expect(a.init_args.to_a).to eq([1, 2, 3])

spec/python/pycall/initialize_test.py

@@ -0,0 +1,11 @@
+class InitializeTest(object):
+    def __init__(self, x):
+        if not hasattr(self, 'values'):
+            self.values = []
+        self.values.append(x)
+
+class NewOverrideTest(InitializeTest):
+    def __new__(cls, x):
+        obj = super().__new__(cls)
+        obj.__init__(x)
+        return obj