Fixes for issue #89: bytes, dict, int, list, str

Author: edschofield

future/types/newbytes.py

@@ -11,6 +11,7 @@
 
 from future.utils import istext, isbytes, PY3, with_metaclass
 from future.types import no, issubset
+from future.types.newobject import newobject
 
 
 _builtin_bytes = bytes
@@ -22,10 +23,13 @@
 
 class BaseNewBytes(type):
     def __instancecheck__(cls, instance):
-        return isinstance(instance, _builtin_bytes)
+        if cls == newbytes:
+            return isinstance(instance, _builtin_bytes)
+        else:
+            return issubclass(instance.__class__, cls)
 
 
-class newbytes(with_metaclass(BaseNewBytes, _builtin_bytes)):
+class newbytes(with_metaclass(BaseNewBytes, _builtin_bytes, newobject)):
     """
     A backport of the Python 3 bytes object to Py2
     """

future/types/newdict.py

@@ -19,6 +19,7 @@
 import sys
 
 from future.utils import with_metaclass
+from future.types.newobject import newobject
 
 
 _builtin_dict = dict
@@ -27,9 +28,13 @@
 
 class BaseNewDict(type):
     def __instancecheck__(cls, instance):
-        return isinstance(instance, _builtin_dict)
+        if cls == newdict:
+            return isinstance(instance, _builtin_dict)
+        else:
+            return issubclass(instance.__class__, cls)
+
 
-class newdict(with_metaclass(BaseNewDict, _builtin_dict)):
+class newdict(with_metaclass(BaseNewDict, _builtin_dict, newobject)):
     """
     A backport of the Python 3 dict object to Py2
     """

future/types/newint.py

@@ -11,6 +11,7 @@
 import collections
 
 from future.types.newbytes import newbytes
+from future.types.newobject import newobject
 from future.utils import PY3, isint, istext, isbytes, with_metaclass, native
 
 
@@ -20,11 +21,14 @@
 
 class BaseNewInt(type):
     def __instancecheck__(cls, instance):
-        # Special case for Py2 short or long int
-        return isinstance(instance, (int, long))
+        if cls == newint:
+            # Special case for Py2 short or long int
+            return isinstance(instance, (int, long))
+        else:
+            return issubclass(instance.__class__, cls)
 
 
-class newint(with_metaclass(BaseNewInt, long)):
+class newint(with_metaclass(BaseNewInt, long, newobject)):
     """
     A backport of the Python 3 int object to Py2
     """

future/types/newlist.py

@@ -25,7 +25,11 @@
 
 class BaseNewList(type):
     def __instancecheck__(cls, instance):
-        return isinstance(instance, _builtin_list)
+        if cls == newlist:
+            return isinstance(instance, _builtin_list)
+        else:
+            return issubclass(instance.__class__, cls)
+
 
 class newlist(with_metaclass(BaseNewList, _builtin_list, newobject)):
     """

future/types/newobject.py

@@ -51,6 +51,7 @@ def __iter__(self):
 #     def __instancecheck__(cls, instance):
 #         return isinstance(instance, _builtin_object)
 
+
 class newobject(_builtin_object):
     """
     A magical object class that provides Python 2 compatibility methods::

future/types/newstr.py

@@ -41,10 +41,11 @@
 """
 
 from collections import Iterable
-
 from numbers import Number
+
 from future.utils import PY3, istext, with_metaclass, isnewbytes
 from future.types import no, issubset
+from future.types.newobject import newobject
 
 
 if PY3:
@@ -54,10 +55,13 @@
 
 class BaseNewStr(type):
     def __instancecheck__(cls, instance):
-        return isinstance(instance, unicode)
+        if cls == newstr:
+            return isinstance(instance, unicode)
+        else:
+            return issubclass(instance.__class__, cls)
 
 
-class newstr(with_metaclass(BaseNewStr, unicode)):
+class newstr(with_metaclass(BaseNewStr, unicode, newobject)):
     """
     A backport of the Python 3 str object to Py2
     """