Fixed django#5701 -- Fixed decorators to take the name, attributes, a…

…nd docstring of the function they decorate by adding a modified version of the `functools.wraps` function from Python 2.5. `wraps` has been altered to work with Django's `curry` function and with Python 2.3, which doesn't allow assignment of a function's `__name__` attribute. This fixes severaly annoyances, such as the online documentation for template filters served by the admin app. This change is backwards incompatible if, for some reason, you were relying on the name of a Django decorator instead of the function it decorates.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@7153 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/admin/views/decorators.py

@@ -1,12 +1,18 @@
+import base64
+import md5
+import cPickle as pickle
+try:
+    from functools import wraps
+except ImportError:
+    from django.utils.functional import wraps  # Python 2.3, 2.4 fallback.
+
 from django import http, template
 from django.conf import settings
 from django.contrib.auth.models import User
 from django.contrib.auth import authenticate, login
 from django.shortcuts import render_to_response
 from django.utils.translation import ugettext_lazy, ugettext as _
 from django.utils.safestring import mark_safe
-import base64, md5
-import cPickle as pickle
 
 ERROR_MESSAGE = ugettext_lazy("Please enter a correct username and password. Note that both fields are case-sensitive.")
 LOGIN_FORM_KEY = 'this_is_the_login_form'
@@ -104,4 +110,4 @@ def _checklogin(request, *args, **kwargs):
             else:
                 return _display_login_form(request, ERROR_MESSAGE)
 
-    return _checklogin
+    return wraps(view_func)(_checklogin)

django/contrib/auth/decorators.py

@@ -1,3 +1,8 @@
+try:
+    from functools import wraps, update_wrapper
+except ImportError:
+    from django.utils.functional import wraps, update_wrapper  # Python 2.3, 2.4 fallback.
+
 from django.contrib.auth import REDIRECT_FIELD_NAME
 from django.http import HttpResponseRedirect
 from django.utils.http import urlquote
@@ -51,7 +56,7 @@ def __init__(self, view_func, test_func, login_url=None, redirect_field_name=RED
         self.test_func = test_func
         self.login_url = login_url
         self.redirect_field_name = redirect_field_name
-        self.__name__ = view_func.__name__
+        update_wrapper(self, view_func)
 
     def __get__(self, obj, cls=None):
         view_func = self.view_func.__get__(obj, cls)

django/template/defaultfilters.py

@@ -2,6 +2,10 @@
 
 import re
 import random as random_module
+try:
+    from functools import wraps
+except ImportError:
+    from django.utils.functional import wraps  # Python 2.3, 2.4 fallback.
 
 from django.template import Variable, Library
 from django.conf import settings
@@ -35,7 +39,7 @@ def _dec(*args, **kwargs):
     for attr in ('is_safe', 'needs_autoescape'):
         if hasattr(func, attr):
             setattr(_dec, attr, getattr(func, attr))
-    return _dec
+    return wraps(func)(_dec)
 
 ###################
 # STRINGS         #

django/utils/decorators.py

@@ -1,6 +1,10 @@
 "Functions that help with dynamically creating decorators for views."
 
 import types
+try:
+    from functools import wraps
+except ImportError:
+    from django.utils.functional import wraps  # Python 2.3, 2.4 fallback.
 
 def decorator_from_middleware(middleware_class):
     """
@@ -53,5 +57,5 @@ def _wrapped_view(request, *args, **kwargs):
                 if result is not None:
                     return result
             return response
-        return _wrapped_view
+        return wraps(view_func)(_wrapped_view)
     return _decorator_from_middleware

django/utils/functional.py

@@ -1,8 +1,120 @@
+# License for code in this file that was taken from Python 2.5.
+
+# PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2
+# --------------------------------------------
+#
+# 1. This LICENSE AGREEMENT is between the Python Software Foundation
+# ("PSF"), and the Individual or Organization ("Licensee") accessing and
+# otherwise using this software ("Python") in source or binary form and
+# its associated documentation.
+#
+# 2. Subject to the terms and conditions of this License Agreement, PSF
+# hereby grants Licensee a nonexclusive, royalty-free, world-wide
+# license to reproduce, analyze, test, perform and/or display publicly,
+# prepare derivative works, distribute, and otherwise use Python
+# alone or in any derivative version, provided, however, that PSF's
+# License Agreement and PSF's notice of copyright, i.e., "Copyright (c)
+# 2001, 2002, 2003, 2004, 2005, 2006, 2007 Python Software Foundation;
+# All Rights Reserved" are retained in Python alone or in any derivative
+# version prepared by Licensee.
+#
+# 3. In the event Licensee prepares a derivative work that is based on
+# or incorporates Python or any part thereof, and wants to make
+# the derivative work available to others as provided herein, then
+# Licensee hereby agrees to include in any such work a brief summary of
+# the changes made to Python.
+#
+# 4. PSF is making Python available to Licensee on an "AS IS"
+# basis.  PSF MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR
+# IMPLIED.  BY WAY OF EXAMPLE, BUT NOT LIMITATION, PSF MAKES NO AND
+# DISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS
+# FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF PYTHON WILL NOT
+# INFRINGE ANY THIRD PARTY RIGHTS.
+#
+# 5. PSF SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON
+# FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS
+# A RESULT OF MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON,
+# OR ANY DERIVATIVE THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.
+#
+# 6. This License Agreement will automatically terminate upon a material
+# breach of its terms and conditions.
+#
+# 7. Nothing in this License Agreement shall be deemed to create any
+# relationship of agency, partnership, or joint venture between PSF and
+# Licensee.  This License Agreement does not grant permission to use PSF
+# trademarks or trade name in a trademark sense to endorse or promote
+# products or services of Licensee, or any third party.
+#
+# 8. By copying, installing or otherwise using Python, Licensee
+# agrees to be bound by the terms and conditions of this License
+# Agreement.
+
+
 def curry(_curried_func, *args, **kwargs):
     def _curried(*moreargs, **morekwargs):
         return _curried_func(*(args+moreargs), **dict(kwargs, **morekwargs))
     return _curried
 
+### Begin from Python 2.5 functools.py ########################################
+
+# Summary of changes made to the Python 2.5 code below:
+#   * swapped ``partial`` for ``curry`` to maintain backwards-compatibility
+#     in Django.
+#   * Wrapped the ``setattr`` call in ``update_wrapper`` with a try-except
+#     block to make it compatible with Python 2.3, which doesn't allow
+#     assigning to ``__name__``.
+
+# Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007 Python Software Foundation.
+# All Rights Reserved.
+
+###############################################################################
+
+# update_wrapper() and wraps() are tools to help write
+# wrapper functions that can handle naive introspection
+
+WRAPPER_ASSIGNMENTS = ('__module__', '__name__', '__doc__')
+WRAPPER_UPDATES = ('__dict__',)
+def update_wrapper(wrapper,
+                   wrapped,
+                   assigned = WRAPPER_ASSIGNMENTS,
+                   updated = WRAPPER_UPDATES):
+    """Update a wrapper function to look like the wrapped function
+
+       wrapper is the function to be updated
+       wrapped is the original function
+       assigned is a tuple naming the attributes assigned directly
+       from the wrapped function to the wrapper function (defaults to
+       functools.WRAPPER_ASSIGNMENTS)
+       updated is a tuple naming the attributes off the wrapper that
+       are updated with the corresponding attribute from the wrapped
+       function (defaults to functools.WRAPPER_UPDATES)
+    """
+    for attr in assigned:
+        try:
+            setattr(wrapper, attr, getattr(wrapped, attr))
+        except TypeError: # Python 2.3 doesn't allow assigning to __name__.
+            pass
+    for attr in updated:
+        getattr(wrapper, attr).update(getattr(wrapped, attr))
+    # Return the wrapper so this can be used as a decorator via curry()
+    return wrapper
+
+def wraps(wrapped,
+          assigned = WRAPPER_ASSIGNMENTS,
+          updated = WRAPPER_UPDATES):
+    """Decorator factory to apply update_wrapper() to a wrapper function
+
+       Returns a decorator that invokes update_wrapper() with the decorated
+       function as the wrapper argument and the arguments to wraps() as the
+       remaining arguments. Default arguments are as for update_wrapper().
+       This is a convenience function to simplify applying curry() to
+       update_wrapper().
+    """
+    return curry(update_wrapper, wrapped=wrapped,
+                 assigned=assigned, updated=updated)
+
+### End from Python 2.5 functools.py ##########################################
+
 def memoize(func, cache, num_args):
     """
     Wrap a function so that results for any argument tuple are stored in
@@ -18,7 +130,7 @@ def wrapper(*args):
         result = func(*args)
         cache[mem_args] = result
         return result
-    return wrapper
+    return wraps(func)(wrapper)
 
 class Promise(object):
     """
@@ -110,7 +222,7 @@ def __wrapper__(*args, **kw):
         # Creates the proxy object, instead of the actual value.
         return __proxy__(args, kw)
 
-    return __wrapper__
+    return wraps(func)(__wrapper__)
 
 def allow_lazy(func, *resultclasses):
     """
@@ -126,4 +238,4 @@ def wrapper(*args, **kwargs):
         else:
             return func(*args, **kwargs)
         return lazy(func, *resultclasses)(*args, **kwargs)
-    return wrapper
+    return wraps(func)(wrapper)

django/views/decorators/cache.py

@@ -11,6 +11,11 @@
 account on caching -- just like the middleware does.
 """
 
+try:
+    from functools import wraps
+except ImportError:
+    from django.utils.functional import wraps  # Python 2.3, 2.4 fallback.
+
 from django.utils.decorators import decorator_from_middleware
 from django.utils.cache import patch_cache_control, add_never_cache_headers
 from django.middleware.cache import CacheMiddleware
@@ -26,7 +31,7 @@ def _cache_controlled(request, *args, **kw):
             patch_cache_control(response, **kwargs)
             return response
 
-        return _cache_controlled
+        return wraps(viewfunc)(_cache_controlled)
 
     return _cache_controller
 
@@ -39,4 +44,4 @@ def _wrapped_view_func(request, *args, **kwargs):
         response = view_func(request, *args, **kwargs)
         add_never_cache_headers(response)
         return response
-    return _wrapped_view_func
+    return wraps(view_func)(_wrapped_view_func)

django/views/decorators/http.py

@@ -2,6 +2,11 @@
 Decorators for views based on HTTP headers.
 """
 
+try:
+    from functools import wraps
+except ImportError:
+    from django.utils.functional import wraps  # Python 2.3, 2.4 fallback.
+
 from django.utils.decorators import decorator_from_middleware
 from django.middleware.http import ConditionalGetMiddleware
 from django.http import HttpResponseNotAllowed
@@ -24,7 +29,7 @@ def inner(request, *args, **kwargs):
             if request.method not in request_method_list:
                 return HttpResponseNotAllowed(request_method_list)
             return func(request, *args, **kwargs)
-        return inner
+        return wraps(func)(inner)
     return decorator
 
 require_GET = require_http_methods(["GET"])

django/views/decorators/vary.py

@@ -1,3 +1,8 @@
+try:
+    from functools import wraps
+except ImportError:
+    from django.utils.functional import wraps  # Python 2.3, 2.4 fallback.
+
 from django.utils.cache import patch_vary_headers
 
 def vary_on_headers(*headers):
@@ -16,7 +21,7 @@ def inner_func(*args, **kwargs):
             response = func(*args, **kwargs)
             patch_vary_headers(response, headers)
             return response
-        return inner_func
+        return wraps(func)(inner_func)
     return decorator
 
 def vary_on_cookie(func):
@@ -32,4 +37,4 @@ def inner_func(*args, **kwargs):
         response = func(*args, **kwargs)
         patch_vary_headers(response, ('Cookie',))
         return response
-    return inner_func
+    return wraps(func)(inner_func)

tests/regressiontests/decorators/models.py

@@ -0,0 +1,2 @@
+# A models.py so that tests run.
+

tests/regressiontests/decorators/tests.py

@@ -0,0 +1,56 @@
+from unittest import TestCase
+from sys import version_info
+
+from django.http import HttpResponse
+from django.utils.functional import allow_lazy, lazy, memoize
+from django.views.decorators.http import require_http_methods, require_GET, require_POST
+from django.views.decorators.vary import vary_on_headers, vary_on_cookie
+from django.views.decorators.cache import cache_page, never_cache, cache_control
+from django.contrib.auth.decorators import login_required, permission_required, user_passes_test
+from django.contrib.admin.views.decorators import staff_member_required
+
+def fully_decorated(request):
+    """Expected __doc__"""
+    return HttpResponse('<html><body>dummy</body></html>')
+fully_decorated.anything = "Expected __dict__"
+
+# django.views.decorators.http
+fully_decorated = require_http_methods(["GET"])(fully_decorated)
+fully_decorated = require_GET(fully_decorated)
+fully_decorated = require_POST(fully_decorated)
+
+# django.views.decorators.vary
+fully_decorated = vary_on_headers('Accept-language')(fully_decorated)
+fully_decorated = vary_on_cookie(fully_decorated)
+
+# django.views.decorators.cache
+fully_decorated = cache_page(60*15)(fully_decorated)
+fully_decorated = cache_control(private=True)(fully_decorated)
+fully_decorated = never_cache(fully_decorated)
+
+# django.contrib.auth.decorators
+fully_decorated = user_passes_test(lambda u:True)(fully_decorated)
+fully_decorated = login_required(fully_decorated)
+fully_decorated = permission_required('change_world')(fully_decorated)
+
+# django.contrib.admin.views.decorators
+fully_decorated = staff_member_required(fully_decorated)
+
+# django.utils.functional
+fully_decorated = memoize(fully_decorated, {}, 1)
+fully_decorated = allow_lazy(fully_decorated)
+fully_decorated = lazy(fully_decorated)
+
+class DecoratorsTest(TestCase):
+
+    def test_attributes(self):
+        """
+        Tests that django decorators set certain attributes of the wrapped
+        function.
+        """
+        # Only check __name__ on Python 2.4 or later since __name__ can't be
+        # assigned to in earlier Python versions.
+        if version_info[0] >= 2 and version_info[1] >= 4:
+            self.assertEquals(fully_decorated.__name__, 'fully_decorated')
+        self.assertEquals(fully_decorated.__doc__, 'Expected __doc__')
+        self.assertEquals(fully_decorated.__dict__['anything'], 'Expected __dict__')