From c6e8e5d9f068210d25f501b2aae4192d1c01185c Mon Sep 17 00:00:00 2001 From: Luke Plant Date: Mon, 19 Oct 2009 21:48:06 +0000 Subject: [PATCH] Fixed non-standard introspection support in LazyObject. LazyObject called a public method ``get_all_members`` on wrapped objects in order to allow introspection. This could easily cause name clashes with existing methods on wrapped objects, and so has been changed to use the standard methods. This could be slightly backwards-incompatible, in obscure cases, if the undocumented LazyObject has been used externally. git-svn-id: http://code.djangoproject.com/svn/django/trunk@11636 bcc190cf-cafb-0310-a4f2-bffc1f526a37 --- django/conf/__init__.py | 8 ++++---- django/core/files/storage.py | 4 ---- django/utils/functional.py | 10 +++++++--- docs/releases/1.2-alpha.txt | 28 ++++++++++++++++++++++++++++ 4 files changed, 39 insertions(+), 11 deletions(-) create mode 100644 docs/releases/1.2-alpha.txt diff --git a/django/conf/__init__.py b/django/conf/__init__.py index 7bc7ae9508..7fbfd26534 100644 --- a/django/conf/__init__.py +++ b/django/conf/__init__.py @@ -108,9 +108,6 @@ class Settings(object): os.environ['TZ'] = self.TIME_ZONE time.tzset() - def get_all_members(self): - return dir(self) - class UserSettingsHolder(object): """ Holder for user configured settings. @@ -129,8 +126,11 @@ class UserSettingsHolder(object): def __getattr__(self, name): return getattr(self.default_settings, name) - def get_all_members(self): + def __dir__(self): return dir(self) + dir(self.default_settings) + # For Python < 2.6: + __members__ = property(lambda self: self.__dir__()) + settings = LazySettings() diff --git a/django/core/files/storage.py b/django/core/files/storage.py index e183c17dd3..96c0b54623 100644 --- a/django/core/files/storage.py +++ b/django/core/files/storage.py @@ -118,10 +118,6 @@ class Storage(object): """ raise NotImplementedError() - # Needed by django.utils.functional.LazyObject (via DefaultStorage). - def get_all_members(self): - return self.__members__ - class FileSystemStorage(Storage): """ Standard filesystem storage diff --git a/django/utils/functional.py b/django/utils/functional.py index 52969cd43a..e12ef3b813 100644 --- a/django/utils/functional.py +++ b/django/utils/functional.py @@ -266,9 +266,6 @@ class LazyObject(object): def __getattr__(self, name): if self._wrapped is None: self._setup() - if name == "__members__": - # Used to implement dir(obj) - return self._wrapped.get_all_members() return getattr(self._wrapped, name) def __setattr__(self, name, value): @@ -286,6 +283,13 @@ class LazyObject(object): """ raise NotImplementedError + # introspection support: + __members__ = property(lambda self: self.__dir__()) + + def __dir__(self): + if self._wrapped is None: + self._setup() + return dir(self._wrapped) class SimpleLazyObject(LazyObject): """ diff --git a/docs/releases/1.2-alpha.txt b/docs/releases/1.2-alpha.txt new file mode 100644 index 0000000000..0df2103486 --- /dev/null +++ b/docs/releases/1.2-alpha.txt @@ -0,0 +1,28 @@ + +Backwards-incompatible changes +============================== + +LazyObject +---------- + +``LazyObject`` is an undocumented utility class used for lazily wrapping other +objects of unknown type. In Django 1.1 and earlier, it handled introspection in +a non-standard way, depending on wrapped objects implementing a public method +``get_all_members()``. Since this could easily lead to name clashes, it has been +changed to use the standard method, involving ``__members__`` and ``__dir__()``. +If you used ``LazyObject`` in your own code, and implemented the +``get_all_members()`` method for wrapped objects, you need to make the following +changes: + + * If your class does not have special requirements for introspection (i.e. you + have not implemented ``__getattr__()`` or other methods that allow for + attributes not discoverable by normal mechanisms), you can simply remove the + ``get_all_members()`` method. The default implementation on ``LazyObject`` + will do the right thing. + + * If you have more complex requirements for introspection, first rename the + ``get_all_members()`` method to ``__dir__()``. This is the standard method, + from Python 2.6 onwards, for supporting introspection. If you are require + support for Python < 2.6, add the following code to the class:: + + __members__ = property(lambda self: self.__dir__())