Remove fast-path __new__ for newdict; add explicit comments for newbytes and newstr

Author: edschofield

future/tests/test_dict.py

@@ -22,6 +22,17 @@ def test_dict_empty(self):
         """
         self.assertEqual(dict(), {})
 
+    def test_dict_dict(self):
+        """
+        Exrapolated from issue #50 -- newlist(newlist([...]))
+        """
+        d = dict({1: 2, 2: 4, 3: 9})
+        d2 = dict(d)
+        self.assertEqual(len(d2), 3)
+        self.assertEqual(d2, d)
+        self.assertTrue(isinstance(d2, dict))
+        self.assertTrue(type(d2) == dict)
+
     def test_dict_eq(self):
         d = self.d1
         self.assertEqual(dict(d), d)

future/types/newbytes.py

@@ -60,6 +60,9 @@ def __new__(cls, *args, **kwargs):
         # this to be True for all unicode string subclasses. Warning:
         # This may render newstr un-subclassable.
         if type(args[0]) == newbytes:
+            # Special-case: for consistency with Py3.3, we return the same object
+            # (with the same id) if a newbytes object is passed into the
+            # newbytes constructor.
             return args[0]
         elif isinstance(args[0], _builtin_bytes):
             value = args[0]

future/types/newdict.py

@@ -91,7 +91,7 @@ def __new__(cls, *args, **kwargs):
         if len(args) == 0:
             return super(newdict, cls).__new__(cls)
         elif type(args[0]) == newdict:
-            return args[0]
+            value = args[0]
         else:
             value = args[0]
         return super(newdict, cls).__new__(cls, value)

future/types/newstr.py

@@ -82,7 +82,8 @@ def __new__(cls, *args, **kwargs):
         if len(args) == 0:
             return super(newstr, cls).__new__(cls)
         # Special case: If someone requests str(str(u'abc')), return the same
-        # object (same id) for consistency with Py3.3
+        # object (same id) for consistency with Py3.3. This is not true for
+        # other objects like list or dict.
         elif type(args[0]) == newstr and cls == newstr:
             return args[0]
         elif isinstance(args[0], unicode):