Issue #4608: urllib.request.urlopen does not return an iterable object

Lib/test/test_urllib.py

@@ -110,8 +110,9 @@ def test_iter(self):
         # Test iterator
         # Don't need to count number of iterations since test would fail the
         # instant it returned anything beyond the first line from the
-        # comparison
+        # comparison.
-        for line in self.returned_obj.__iter__():
+        # Use the iterator in the usual implicit way to test for ticket #4608.
+        for line in self.returned_obj:
             self.assertEqual(line, self.text)
 
 class ProxyTests(unittest.TestCase):

Lib/urllib/response.py

@@ -23,10 +23,14 @@ def __init__(self, fp):
             self.fileno = self.fp.fileno
         else:
             self.fileno = lambda: None
-        if hasattr(self.fp, "__iter__"):
+
-            self.__iter__ = self.fp.__iter__
+    def __iter__(self):
-            if hasattr(self.fp, "__next__"):
+        # Assigning `__iter__` to the instance doesn't work as intended
-                self.__next__ = self.fp.__next__
+        # because the iter builtin does something like `cls.__iter__(obj)`
+        # and thus fails to find the _bound_ method `obj.__iter__`.
+        # Returning just `self.fp` works for built-in file objects but
+        # might not work for general file-like objects.
+        return iter(self.fp)
 
     def __repr__(self):
         return '<%s at %r whose fp = %r>' % (self.__class__.__name__,

Misc/ACKS

@@ -325,6 +325,7 @@ Lele Gaifax
 Santiago Gala
 Yitzchak Gale
 Quentin Gallet-Gilles
+Riccardo Attilio Galli
 Raymund Galvin
 Nitin Ganatra
 Fred Gansevles