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changeset: 89158:f56b98143792 user: R David Murray rdmurray@bitdance.com date: Tue Feb 11 18:34:22 2014 -0500 files: Doc/library/functions.rst Doc/reference/datamodel.rst Doc/whatsnew/3.4.rst description: whatsnew: object.__format__ raises TypeError on non-empty string. See issues #7994 and #9856. I also modified with wording of the format doc entry to better match what really happens, and added a versionchanged to the datamodel object.__format__ section. diff -r 2ba583191550 -r f56b98143792 Doc/library/functions.rst --- a/Doc/library/functions.rst Tue Feb 11 18:40:56 2014 +0100 +++ b/Doc/library/functions.rst Tue Feb 11 18:34:22 2014 -0500 @@ -540,12 +540,13 @@ A call to ``format(value, format_spec)`` is translated to ``type(value).__format__(format_spec)`` which bypasses the instance dictionary when searching for the value's :meth:`__format__` method. A - :exc:`TypeError` exception is raised if the method is not found or if either - the *format_spec* or the return value are not strings. + :exc:`TypeError` exception is raised if the method search reaches + :mod:`object` and the *format_spec* is non-empty, or if either the + *format_spec* or the return value are not strings. - .. versionadded:: 3.4 + .. versionchanged:: 3.4 ``object().__format__(format_spec)`` raises :exc:`TypeError` - if *format_spec* is not empty string. + if *format_spec* is not an empty string. .. _func-frozenset: diff -r 2ba583191550 -r f56b98143792 Doc/reference/datamodel.rst --- a/Doc/reference/datamodel.rst Tue Feb 11 18:40:56 2014 +0100 +++ b/Doc/reference/datamodel.rst Tue Feb 11 18:34:22 2014 -0500 @@ -1226,6 +1226,10 @@ The return value must be a string object. + .. versionchanged:: 3.4 + The __format__ method of ``object`` itself raises a :exc:`TypeError` + if passed any non-empty string. + .. _richcmpfuncs: .. method:: object.__lt__(self, other) diff -r 2ba583191550 -r f56b98143792 Doc/whatsnew/3.4.rst --- a/Doc/whatsnew/3.4.rst Tue Feb 11 18:40:56 2014 +0100 +++ b/Doc/whatsnew/3.4.rst Tue Feb 11 18:34:22 2014 -0500 @@ -1600,6 +1600,15 @@ * :class:`inspect.Signature`: positional-only parameters are now required to have a valid name. +* :meth:`object.__format__` no longer accepts non-empty format strings, it now + raises a :exc:`TypeError` instead. Using a non-empty string has been + deprecated since Python 3.2. This change has been made to prevent a + situation where previously working (but incorrect) code would start failing + if an object gained a __format__ method, which means that your code may now + raise a :exc:`TypeError` if you are using an ``'s'`` format code with objects + that do not have a __format__ method that handles it. See :issue:`7994` for + background. + Code Cleanups ------------- /rdmurray@bitdance.com