Clarify that we're only doing PY2 classes, and add tests

In PY3, we're falling back to the builtin implementation by relying on __build_class__.

Add tests that show that something is going wrong with attribute lookup.

byterun/pyobj.py

@@ -72,7 +72,7 @@ def __call__(self, *args, **kwargs):
             try:
                 callargs = inspect.getcallargs(self._func, *args, **kwargs)
             except Exception as e:
-                import pudb;pudb.set_trace() # -={XX}=-={XX}=-={XX}=- 
+                # import pudb;pudb.set_trace() # -={XX}=-={XX}=-={XX}=-
                 raise
         frame = self._vm.make_frame(
             self.func_code, callargs, self.func_globals, self.func_locals
@@ -86,55 +86,55 @@ def __call__(self, *args, **kwargs):
             retval = self._vm.run_frame(frame)
         return retval
 
+if PY2:
+    class Class(object):
+        def __init__(self, name, bases, methods):
+            self.__name__ = name
+            self.__bases__ = bases
+            self.locals = dict(methods)
 
-class Class(object):
-    def __init__(self, name, bases, methods):
-        self.__name__ = name
-        self.__bases__ = bases
-        self.locals = dict(methods)
+        def __call__(self, *args, **kw):
+            return Object(self, self.locals, args, kw)
 
-    def __call__(self, *args, **kw):
-        return Object(self, self.locals, args, kw)
+        def __repr__(self):         # pragma: no cover
+            return '<Class %s at 0x%08x>' % (self.__name__, id(self))
 
-    def __repr__(self):         # pragma: no cover
-        return '<Class %s at 0x%08x>' % (self.__name__, id(self))
-
-    def __getattr__(self, name):
-        try:
-            val = self.locals[name]
-        except KeyError:
-            raise AttributeError("Fooey: %r" % (name,))
-        # Check if we have a descriptor
-        get = getattr(val, '__get__', None)
-        if get:
-            return get(None, self)
-        # Not a descriptor, return the value.
-        return val
-
-
-class Object(object):
-    def __init__(self, _class, methods, args, kw):
-        self._class = _class
-        self.locals = methods
-        if '__init__' in methods:
-            methods['__init__'](self, *args, **kw)
-
-    def __repr__(self):         # pragma: no cover
-        return '<%s Instance at 0x%08x>' % (self._class.__name__, id(self))
-
-    def __getattr__(self, name):
-        try:
-            val = self.locals[name]
-        except KeyError:
-            raise AttributeError(
-                "%r object has no attribute %r" % (self._class.__name__, name)
-            )
-        # Check if we have a descriptor
-        get = getattr(val, '__get__', None)
-        if get:
-            return get(self, self._class)
-        # Not a descriptor, return the value.
-        return val
+        def __getattr__(self, name):
+            try:
+                val = self.locals[name]
+            except KeyError:
+                raise AttributeError("Fooey: %r" % (name,))
+            # Check if we have a descriptor
+            get = getattr(val, '__get__', None)
+            if get:
+                return get(None, self)
+            # Not a descriptor, return the value.
+            return val
+
+
+    class Object(object):
+        def __init__(self, _class, methods, args, kw):
+            self._class = _class
+            self.locals = methods
+            if '__init__' in methods:
+                methods['__init__'](self, *args, **kw)
+
+        def __repr__(self):         # pragma: no cover
+            return '<%s Instance at 0x%08x>' % (self._class.__name__, id(self))
+
+        def __getattr__(self, name):
+            try:
+                val = self.locals[name]
+            except KeyError:
+                raise AttributeError(
+                    "%r object has no attribute %r" % (self._class.__name__, name)
+                )
+            # Check if we have a descriptor
+            get = getattr(val, '__get__', None)
+            if get:
+                return get(self, self._class)
+            # Not a descriptor, return the value.
+            return val
 
 
 class Method(object):

byterun/pyvm2.py

@@ -15,7 +15,9 @@
 
 PY3, PY2 = six.PY3, not six.PY3
 
-from .pyobj import Frame, Block, Method, Object, Function, Class, Generator
+from .pyobj import Frame, Block, Method, Function, Generator
+if PY2:
+    from .pyobj import Class, Object
 
 log = logging.getLogger(__name__)
 
@@ -910,12 +912,12 @@ def byte_CALL_FUNCTION_VAR_KW(self, arg):
         return self.call_function(arg, args, kwargs)
 
     def isinstance(self, obj, cls):
-        if isinstance(obj, Object):
-            return issubclass(obj._class, cls)
-        elif isinstance(cls, Class):
-            return False
-        else:
-            return isinstance(obj, cls)
+        if PY2:
+            if isinstance(obj, Object):
+                return issubclass(obj._class, cls)
+            elif isinstance(cls, Class):
+                return False
+        return isinstance(obj, cls)
 
     def call_function(self, arg, args, kwargs):
         lenKw, lenPos = divmod(arg, 256)
@@ -983,16 +985,18 @@ def byte_EXEC_STMT(self):
         stmt, globs, locs = self.popn(3)
         six.exec_(stmt, globs, locs)
 
-    def byte_BUILD_CLASS(self):
-        name, bases, methods = self.popn(3)
-        self.push(Class(name, bases, methods))
+    if PY2:
+        def byte_BUILD_CLASS(self):
+            name, bases, methods = self.popn(3)
+            self.push(Class(name, bases, methods))
 
-    def byte_LOAD_BUILD_CLASS(self):
-        # New in py3
-        self.push(__build_class__)
+    elif PY3:
+        def byte_LOAD_BUILD_CLASS(self):
+            # New in py3
+            self.push(__build_class__)
 
-    def byte_STORE_LOCALS(self):
-        self.frame.f_locals = self.pop()
+        def byte_STORE_LOCALS(self):
+            self.frame.f_locals = self.pop()
 
     if 0:   # Not in py2.7
         def byte_SET_LINENO(self, lineno):

tests/test_basic.py

@@ -310,6 +310,40 @@ class SubThing(Thing):
             print(st.foo())
             """)
 
+    def test_subclass_attribute(self):
+        self.assert_ok("""\
+            class Thing(object):
+                def __init__(self):
+                    self.foo = 17
+            class SubThing(Thing):
+                pass
+            st = SubThing()
+            print(st.foo)
+            """)
+
+    def test_subclass_attributes_not_shared(self):
+        self.assert_ok("""\
+            class Thing(object):
+                foo = 17
+            class SubThing(Thing):
+                foo = 25
+            st = SubThing()
+            t = Thing()
+            assert st.foo == 25
+            assert t.foo == 17
+            """)
+
+    def test_subclass_attributes_dynamic(self):
+        self.assert_ok("""\
+            class Foo(object):
+                pass
+            class Bar(Foo):
+                pass
+            b = Bar()
+            Foo.baz = 3
+            assert b.baz == 3
+            """)
+
     def test_attribute_access(self):
         self.assert_ok("""\
             class Thing(object):