Fixed #5701 -- Fixed decorators to take the name, attributes, and 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/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"
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+# DISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS
+# FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF PYTHON WILL NOT
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+# A RESULT OF MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON,
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+# trademarks or trade name in a trademark sense to endorse or promote
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+# 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 memoize(func, cache, num_args):
         result = func(*args)
         cache[mem_args] = result
         return result
-    return wrapper
+    return wraps(func)(wrapper)
 
 class Promise(object):
     """
@@ -110,7 +222,7 @@ def lazy(func, *resultclasses):
         # 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 allow_lazy(func, *resultclasses):
         else:
             return func(*args, **kwargs)
         return lazy(func, *resultclasses)(*args, **kwargs)
-    return wrapper
+    return wraps(func)(wrapper)