- The fix for issue Pylons#461 (which made

  it possible for instance methods to be used as view callables) introduced a
  backwards incompatibility when methods that declared only a request
  argument were used.  See Pylons#503

Fixes Pylons#503

CHANGES.txt

@@ -11,6 +11,11 @@ Bug Fixes
   because it mistakenly detects that a route was matched when, in fact, it
   was not.
 
+- The fix for issue https://github.com/Pylons/pyramid/issues/461 (which made
+  it possible for instance methods to be used as view callables) introduced a
+  backwards incompatibility when methods that declared only a request
+  argument were used.  See https://github.com/Pylons/pyramid/issues/503
+
 1.3b3 (2012-03-17)
 ==================
 

pyramid/compat.py

@@ -1,3 +1,4 @@
+import inspect
 import platform
 import sys
 import types
@@ -185,8 +186,10 @@ def is_nonstr_iter(v):
 
 if PY3: # pragma: no cover
     im_func = '__func__'
+    im_self = '__self__'
 else:
     im_func = 'im_func'
+    im_self = 'im_self'
 
 try: # pragma: no cover
     import configparser
@@ -237,3 +240,7 @@ def unquote_bytes_to_wsgi(bytestring):
     from urlparse import unquote as unquote_to_bytes
     def unquote_bytes_to_wsgi(bytestring):
         return unquote_to_bytes(bytestring)
+
+def is_bound_method(ob):
+    return inspect.ismethod(ob) and getattr(ob, im_self, None) is not None
+

pyramid/config/views.py

@@ -41,6 +41,7 @@
     im_func,
     url_quote,
     WIN,
+    is_bound_method,
     )
 
 from pyramid.exceptions import (
@@ -140,18 +141,7 @@ def __call__(self, view):
                                 self.decorated_view(
                                     self.rendered_view(
                                         self.mapped_view(
-                                            self.text_wrapped_view(
-                                                view))))))))))
-
-    @wraps_view
-    def text_wrapped_view(self, view):
-        # if the method is an instance method, we need to wrap it in order
-        # to be able to assign a __text__ value to it later.  see #461.
-        if inspect.ismethod(view):
-            def text_wrapper(context, request):
-                return view(context, request)
-            return text_wrapper
-        return view
+                                                view)))))))))
 
     @wraps_view
     def mapped_view(self, view):
@@ -428,9 +418,16 @@ def map_nonclass(self, view):
         elif self.attr:
             mapped_view = self.map_nonclass_attr(view)
         if inspect.isroutine(mapped_view):
-            # we potentially mutate an unwrapped view here if it's a function;
-            # we do this to avoid function call overhead of injecting another
-            # wrapper
+            # This branch will be true if the view is a function or a method.
+            # We potentially mutate an unwrapped object here if it's a
+            # function.  We do this to avoid function call overhead of
+            # injecting another wrapper.  However, we must wrap if the
+            # function is a bound method because we can't set attributes on a
+            # bound method.
+            if is_bound_method(view):
+                _mapped_view = mapped_view
+                def mapped_view(context, request):
+                    return _mapped_view(context, request)
             if self.attr is not None:
                 mapped_view.__text__ = 'attr %s of %s' % (
                     self.attr, object_description(view))

pyramid/tests/test_config/test_views.py

@@ -230,6 +230,18 @@ def index(self, context, request):
         result = wrapper(None, None)
         self.assertEqual(result, 'OK')
 
+    def test_add_view_as_instancemethod_requestonly(self):
+        from pyramid.renderers import null_renderer
+        class View:
+            def index(self, request):
+                return 'OK'
+        view = View()
+        config=self._makeOne(autocommit=True)
+        config.add_view(view=view.index, renderer=null_renderer)
+        wrapper = self._getViewCallable(config)
+        result = wrapper(None, None)
+        self.assertEqual(result, 'OK')
+
     def test_add_view_as_instance_requestonly(self):
         from pyramid.renderers import null_renderer
         class AView: