[Python-checkins] r86578 - in python/branches/py3k: Doc/library/inspect.rst Lib/inspect.py Lib/test/test_inspect.py

Sat Nov 20 17:40:44 CET 2010

Author: michael.foord
Date: Sat Nov 20 17:40:44 2010
New Revision: 86578
Log:
Issue 9732: fetch the method resolution order from the type metaclass directly in getattr_static
Modified:
 python/branches/py3k/Doc/library/inspect.rst
 python/branches/py3k/Lib/inspect.py
 python/branches/py3k/Lib/test/test_inspect.py
Modified: python/branches/py3k/Doc/library/inspect.rst
==============================================================================

--- python/branches/py3k/Doc/library/inspect.rst	(original)
+++ python/branches/py3k/Doc/library/inspect.rst	Sat Nov 20 17:40:44 2010
@@ -587,26 +587,14 @@
 that raise AttributeError). It can also return descriptors objects
 instead of instance members.
 
-There are several cases that will break `getattr_static` or be handled
-incorrectly. These are pathological enough not to worry about (i.e. if you do
-any of these then you deserve to have everything break anyway):
-
-* :data:`~object.__dict__` existing (e.g. as a property) but returning the
- wrong dictionary or even returning something other than a
- dictionary
-* classes created with :data:`~object.__slots__` that have the `__slots__`
- member deleted from the class, or a fake `__slots__` attribute
- attached to the instance, or any other monkeying with
- `__slots__`
-* type objects that lie about their :term:`MRO`
+The only known case that can cause `getattr_static` to trigger code execution,
+and cause it to return incorrect results (or even break), is where a class uses
+:data:`~object.__slots__` and provides a `__dict__` member using a property or
+descriptor. If you find other cases please report them so they can be fixed
+or documented.
 
-.. note::
-
- Classes that override :data:`~object.__mro__` as a property will have this
- code executed by `getattr_static`.
-
-Descriptors are not resolved (for example slot descriptors or
-getset descriptors on objects implemented in C). The descriptor
+`getattr_static` does not resolve descriptors, for example slot descriptors or
+getset descriptors on objects implemented in C. The descriptor object
 is returned instead of the underlying attribute.
 
 You can handle these with code like the following. Note that
Modified: python/branches/py3k/Lib/inspect.py
==============================================================================
--- python/branches/py3k/Lib/inspect.py	(original)
+++ python/branches/py3k/Lib/inspect.py	Sat Nov 20 17:40:44 2010
@@ -1060,6 +1060,9 @@
 
 _sentinel = object()
 
+def _static_getmro(klass):
+ return type.__dict__['__mro__'].__get__(klass)
+
 def _check_instance(obj, attr):
 instance_dict = {}
 try:
@@ -1070,7 +1073,7 @@
 
 
 def _check_class(klass, attr):
- for entry in getmro(klass):
+ for entry in _static_getmro(klass):
 try:
 return entry.__dict__[attr]
 except KeyError:
@@ -1110,7 +1113,7 @@
 
 if obj is klass:
 # for types we check the metaclass too
- for entry in getmro(type(klass)):
+ for entry in _static_getmro(type(klass)):
 try:
 return entry.__dict__[attr]
 except KeyError:
Modified: python/branches/py3k/Lib/test/test_inspect.py
==============================================================================
--- python/branches/py3k/Lib/test/test_inspect.py	(original)
+++ python/branches/py3k/Lib/test/test_inspect.py	Sat Nov 20 17:40:44 2010
@@ -867,6 +867,22 @@
 self.assertEqual(inspect.getattr_static(Something(), 'foo'), 3)
 self.assertEqual(inspect.getattr_static(Something, 'foo'), 3)
 
+ def test_mro_as_property(self):
+ class Meta(type):
+ @property
+ def __mro__(self):
+ return (object,)
+
+ class Base(object):
+ foo = 3
+
+ class Something(Base, metaclass=Meta):
+ pass
+
+ self.assertEqual(inspect.getattr_static(Something(), 'foo'), 3)
+ self.assertEqual(inspect.getattr_static(Something, 'foo'), 3)
+
+
 def test_main():
 run_unittest(
 TestDecorators, TestRetrievingSourceCode, TestOneliners, TestBuggyCases,
