Most applications are probably going to want to log to a file, so let's start
with that case. Using the :func:`basicConfig` function, we can set up the
-default handler so that debug messages are written to a file::
+default handler so that debug messages are written to a file (in the example,
+we assume that you have the appropriate permissions to create a file called
+*example.log* in the current directory)::
import logging
- LOG_FILENAME = '/tmp/logging_example.out'
+ LOG_FILENAME = 'example.log'
logging.basicConfig(filename=LOG_FILENAME,level=logging.DEBUG)
logging.debug('This message should go to the log file')
import logging
import logging.handlers
- LOG_FILENAME = '/tmp/logging_rotatingfile_example.out'
+ LOG_FILENAME = 'logging_rotatingfile_example.out'
# Set up a specific logger with our desired output level
my_logger = logging.getLogger('MyLogger')
The result should be 6 separate files, each with part of the log history for the
application::
- /tmp/logging_rotatingfile_example.out
- /tmp/logging_rotatingfile_example.out.1
- /tmp/logging_rotatingfile_example.out.2
- /tmp/logging_rotatingfile_example.out.3
- /tmp/logging_rotatingfile_example.out.4
- /tmp/logging_rotatingfile_example.out.5
+ logging_rotatingfile_example.out
+ logging_rotatingfile_example.out.1
+ logging_rotatingfile_example.out.2
+ logging_rotatingfile_example.out.3
+ logging_rotatingfile_example.out.4
+ logging_rotatingfile_example.out.5
-The most current file is always :file:`/tmp/logging_rotatingfile_example.out`,
+The most current file is always :file:`logging_rotatingfile_example.out`,
and each time it reaches the size limit it is renamed with the suffix
``.1``. Each of the existing backup files is renamed to increment the suffix
(``.1`` becomes ``.2``, etc.) and the ``.6`` file is erased.
Configuring Logging
^^^^^^^^^^^^^^^^^^^
-Programmers can configure logging either by creating loggers, handlers, and
-formatters explicitly in a main module with the configuration methods listed
-above (using Python code), or by creating a logging config file. The following
-code is an example of configuring a very simple logger, a console handler, and a
-simple formatter in a Python module::
+Programmers can configure logging in three ways:
+
+1. Creating loggers, handlers, and formatters explicitly using Python
+ code that calls the configuration methods listed above.
+2. Creating a logging config file and reading it using the :func:`fileConfig`
+ function.
+3. Creating a dictionary of configuration information and passing it
+ to the :func:`dictConfig` function.
+
+The following example configures a very simple logger, a console
+handler, and a simple formatter using Python code::
import logging
# create logger
logger = logging.getLogger("simple_example")
logger.setLevel(logging.DEBUG)
+
# create console handler and set level to debug
ch = logging.StreamHandler()
ch.setLevel(logging.DEBUG)
+
# create formatter
formatter = logging.Formatter("%(asctime)s - %(name)s - %(levelname)s - %(message)s")
+
# add formatter to ch
ch.setFormatter(formatter)
+
# add ch to logger
logger.addHandler(ch)
class defined in package `mypackage` and module `mymodule`, where `mypackage`
is available on the Python import path).
+.. versionchanged:: 2.7
+
+In Python 2.7, a new means of configuring logging has been introduced, using
+dictionaries to hold configuration information. This provides a superset of the
+functionality of the config-file-based approach outlined above, and is the
+recommended configuration method for new applications and deployments. Because
+a Python dictionary is used to hold configuration information, and since you
+can populate that dictionary using different means, you have more options for
+configuration. For example, you can use a configuration file in JSON format,
+or, if you have access to YAML processing functionality, a file in YAML
+format, to populate the configuration dictionary. Or, of course, you can
+construct the dictionary in Python code, receive it in pickled form over a
+socket, or use whatever approach makes sense for your application.
+
+Here's an example of the same configuration as above, in YAML format for
+the new dictionary-based approach::
+
+ version: 1
+ formatters:
+ simple:
+ format: format=%(asctime)s - %(name)s - %(levelname)s - %(message)s
+ handlers:
+ console:
+ class: logging.StreamHandler
+ level: DEBUG
+ formatter: simple
+ stream: ext://sys.stdout
+ loggers:
+ simpleExample:
+ level: DEBUG
+ handlers: [console]
+ propagate: no
+ root:
+ level: DEBUG
+ handlers: [console]
+
+For more information about logging using a dictionary, see
+:ref:`logging-config-api`.
+
.. _library-config:
Configuring Logging for a Library
logging.basicConfig(level=logging.DEBUG,
format='%(asctime)s %(levelname)s %(message)s',
- filename='/tmp/myapp.log',
+ filename='myapp.log',
filemode='w')
logging.debug('A debug message')
logging.info('Some information')
logging.warning('A shot across the bows')
The :meth:`basicConfig` method is used to change the configuration defaults,
-which results in output (written to ``/tmp/myapp.log``) which should look
+which results in output (written to ``myapp.log``) which should look
something like the following::
2004-07-02 13:00:08,743 DEBUG A debug message
in :mod:`logging` itself) and defining handlers which are declared either in
:mod:`logging` or :mod:`logging.handlers`.
-
-.. function:: fileConfig(fname, defaults=None, disable_existing_loggers=True)
+.. function:: dictConfig(config)
+
+ Takes the logging configuration from a dictionary. The contents of
+ this dictionary are described in :ref:`logging-config-dictschema`
+ below.
+
+ If an error is encountered during configuration, this function will
+ raise a :exc:`ValueError`, :exc:`TypeError`, :exc:`AttributeError`
+ or :exc:`ImportError` with a suitably descriptive message. The
+ following is a (possibly incomplete) list of conditions which will
+ raise an error:
+
+ * A ``level`` which is not a string or which is a string not
+ corresponding to an actual logging level.
+ * A ``propagate`` value which is not a boolean.
+ * An id which does not have a corresponding destination.
+ * A non-existent handler id found during an incremental call.
+ * An invalid logger name.
+ * Inability to resolve to an internal or external object.
+
+ Parsing is performed by the :class:`DictConfigurator` class, whose
+ constructor is passed the dictionary used for configuration, and
+ has a :meth:`configure` method. The :mod:`logging.config` module
+ has a callable attribute :attr:`dictConfigClass`
+ which is initially set to :class:`DictConfigurator`.
+ You can replace the value of :attr:`dictConfigClass` with a
+ suitable implementation of your own.
+
+ :func:`dictConfig` calls :attr:`dictConfigClass` passing
+ the specified dictionary, and then calls the :meth:`configure` method on
+ the returned object to put the configuration into effect::
+
+ def dictConfig(config):
+ dictConfigClass(config).configure()
+
+ For example, a subclass of :class:`DictConfigurator` could call
+ ``DictConfigurator.__init__()`` in its own :meth:`__init__()`, then
+ set up custom prefixes which would be usable in the subsequent
+ :meth:`configure` call. :attr:`dictConfigClass` would be bound to
+ this new subclass, and then :func:`dictConfig` could be called exactly as
+ in the default, uncustomized state.
+
+.. function:: fileConfig(fname[, defaults])
Reads the logging configuration from a :mod:`configparser`\-format file named
*fname*. This function can be called several times from an application,
- allowing an end user the ability to select from various pre-canned
+ allowing an end user to select from various pre-canned
configurations (if the developer provides a mechanism to present the choices
and load the chosen configuration). Defaults to be passed to the ConfigParser
can be specified in the *defaults* argument.
- If *disable_existing_loggers* is true, any existing loggers that are not
- children of named loggers will be disabled.
-
.. function:: listen(port=DEFAULT_LOGGING_CONFIG_PORT)
:func:`listen`.
+.. _logging-config-dictschema:
+
+Configuration dictionary schema
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Describing a logging configuration requires listing the various
+objects to create and the connections between them; for example, you
+may create a handler named "console" and then say that the logger
+named "startup" will send its messages to the "console" handler.
+These objects aren't limited to those provided by the :mod:`logging`
+module because you might write your own formatter or handler class.
+The parameters to these classes may also need to include external
+objects such as ``sys.stderr``. The syntax for describing these
+objects and connections is defined in :ref:`logging-config-dict-connections`
+below.
+
+Dictionary Schema Details
+"""""""""""""""""""""""""
+
+The dictionary passed to :func:`dictConfig` must contain the following
+keys:
+
+* `version` - to be set to an integer value representing the schema
+ version. The only valid value at present is 1, but having this key
+ allows the schema to evolve while still preserving backwards
+ compatibility.
+
+All other keys are optional, but if present they will be interpreted
+as described below. In all cases below where a 'configuring dict' is
+mentioned, it will be checked for the special ``'()'`` key to see if a
+custom instantiation is required. If so, the mechanism described in
+:ref:`logging-config-dict-userdef` below is used to create an instance;
+otherwise, the context is used to determine what to instantiate.
+
+* `formatters` - the corresponding value will be a dict in which each
+ key is a formatter id and each value is a dict describing how to
+ configure the corresponding Formatter instance.
+
+ The configuring dict is searched for keys ``format`` and ``datefmt``
+ (with defaults of ``None``) and these are used to construct a
+ :class:`logging.Formatter` instance.
+
+* `filters` - the corresponding value will be a dict in which each key
+ is a filter id and each value is a dict describing how to configure
+ the corresponding Filter instance.
+
+ The configuring dict is searched for the key ``name`` (defaulting to the
+ empty string) and this is used to construct a :class:`logging.Filter`
+ instance.
+
+* `handlers` - the corresponding value will be a dict in which each
+ key is a handler id and each value is a dict describing how to
+ configure the corresponding Handler instance.
+
+ The configuring dict is searched for the following keys:
+
+ * ``class`` (mandatory). This is the fully qualified name of the
+ handler class.
+
+ * ``level`` (optional). The level of the handler.
+
+ * ``formatter`` (optional). The id of the formatter for this
+ handler.
+
+ * ``filters`` (optional). A list of ids of the filters for this
+ handler.
+
+ All *other* keys are passed through as keyword arguments to the
+ handler's constructor. For example, given the snippet::
+
+ handlers:
+ console:
+ class : logging.StreamHandler
+ formatter: brief
+ level : INFO
+ filters: [allow_foo]
+ stream : ext://sys.stdout
+ file:
+ class : logging.handlers.RotatingFileHandler
+ formatter: precise
+ filename: logconfig.log
+ maxBytes: 1024
+ backupCount: 3
+
+ the handler with id ``console`` is instantiated as a
+ :class:`logging.StreamHandler`, using ``sys.stdout`` as the underlying
+ stream. The handler with id ``file`` is instantiated as a
+ :class:`logging.handlers.RotatingFileHandler` with the keyword arguments
+ ``filename='logconfig.log', maxBytes=1024, backupCount=3``.
+
+* `loggers` - the corresponding value will be a dict in which each key
+ is a logger name and each value is a dict describing how to
+ configure the corresponding Logger instance.
+
+ The configuring dict is searched for the following keys:
+
+ * ``level`` (optional). The level of the logger.
+
+ * ``propagate`` (optional). The propagation setting of the logger.
+
+ * ``filters`` (optional). A list of ids of the filters for this
+ logger.
+
+ * ``handlers`` (optional). A list of ids of the handlers for this
+ logger.
+
+ The specified loggers will be configured according to the level,
+ propagation, filters and handlers specified.
+
+* `root` - this will be the configuration for the root logger.
+ Processing of the configuration will be as for any logger, except
+ that the ``propagate`` setting will not be applicable.
+
+* `incremental` - whether the configuration is to be interpreted as
+ incremental to the existing configuration. This value defaults to
+ ``False``, which means that the specified configuration replaces the
+ existing configuration with the same semantics as used by the
+ existing :func:`fileConfig` API.
+
+ If the specified value is ``True``, the configuration is processed
+ as described in the section on :ref:`logging-config-dict-incremental`.
+
+* `disable_existing_loggers` - whether any existing loggers are to be
+ disabled. This setting mirrors the parameter of the same name in
+ :func:`fileConfig`. If absent, this parameter defaults to ``True``.
+ This value is ignored if `incremental` is ``True``.
+
+.. _logging-config-dict-incremental:
+
+Incremental Configuration
+"""""""""""""""""""""""""
+
+It is difficult to provide complete flexibility for incremental
+configuration. For example, because objects such as filters
+and formatters are anonymous, once a configuration is set up, it is
+not possible to refer to such anonymous objects when augmenting a
+configuration.
+
+Furthermore, there is not a compelling case for arbitrarily altering
+the object graph of loggers, handlers, filters, formatters at
+run-time, once a configuration is set up; the verbosity of loggers and
+handlers can be controlled just by setting levels (and, in the case of
+loggers, propagation flags). Changing the object graph arbitrarily in
+a safe way is problematic in a multi-threaded environment; while not
+impossible, the benefits are not worth the complexity it adds to the
+implementation.
+
+Thus, when the ``incremental`` key of a configuration dict is present
+and is ``True``, the system will completely ignore any ``formatters`` and
+``filters`` entries, and process only the ``level``
+settings in the ``handlers`` entries, and the ``level`` and
+``propagate`` settings in the ``loggers`` and ``root`` entries.
+
+Using a value in the configuration dict lets configurations to be sent
+over the wire as pickled dicts to a socket listener. Thus, the logging
+verbosity of a long-running application can be altered over time with
+no need to stop and restart the application.
+
+.. _logging-config-dict-connections:
+
+Object connections
+""""""""""""""""""
+
+The schema describes a set of logging objects - loggers,
+handlers, formatters, filters - which are connected to each other in
+an object graph. Thus, the schema needs to represent connections
+between the objects. For example, say that, once configured, a
+particular logger has attached to it a particular handler. For the
+purposes of this discussion, we can say that the logger represents the
+source, and the handler the destination, of a connection between the
+two. Of course in the configured objects this is represented by the
+logger holding a reference to the handler. In the configuration dict,
+this is done by giving each destination object an id which identifies
+it unambiguously, and then using the id in the source object's
+configuration to indicate that a connection exists between the source
+and the destination object with that id.
+
+So, for example, consider the following YAML snippet::
+
+ formatters:
+ brief:
+ # configuration for formatter with id 'brief' goes here
+ precise:
+ # configuration for formatter with id 'precise' goes here
+ handlers:
+ h1: #This is an id
+ # configuration of handler with id 'h1' goes here
+ formatter: brief
+ h2: #This is another id
+ # configuration of handler with id 'h2' goes here
+ formatter: precise
+ loggers:
+ foo.bar.baz:
+ # other configuration for logger 'foo.bar.baz'
+ handlers: [h1, h2]
+
+(Note: YAML used here because it's a little more readable than the
+equivalent Python source form for the dictionary.)
+
+The ids for loggers are the logger names which would be used
+programmatically to obtain a reference to those loggers, e.g.
+``foo.bar.baz``. The ids for Formatters and Filters can be any string
+value (such as ``brief``, ``precise`` above) and they are transient,
+in that they are only meaningful for processing the configuration
+dictionary and used to determine connections between objects, and are
+not persisted anywhere when the configuration call is complete.
+
+The above snippet indicates that logger named ``foo.bar.baz`` should
+have two handlers attached to it, which are described by the handler
+ids ``h1`` and ``h2``. The formatter for ``h1`` is that described by id
+``brief``, and the formatter for ``h2`` is that described by id
+``precise``.
+
+
+.. _logging-config-dict-userdef:
+
+User-defined objects
+""""""""""""""""""""
+
+The schema supports user-defined objects for handlers, filters and
+formatters. (Loggers do not need to have different types for
+different instances, so there is no support in this configuration
+schema for user-defined logger classes.)
+
+Objects to be configured are described by dictionaries
+which detail their configuration. In some places, the logging system
+will be able to infer from the context how an object is to be
+instantiated, but when a user-defined object is to be instantiated,
+the system will not know how to do this. In order to provide complete
+flexibility for user-defined object instantiation, the user needs
+to provide a 'factory' - a callable which is called with a
+configuration dictionary and which returns the instantiated object.
+This is signalled by an absolute import path to the factory being
+made available under the special key ``'()'``. Here's a concrete
+example::
+
+ formatters:
+ brief:
+ format: '%(message)s'
+ default:
+ format: '%(asctime)s %(levelname)-8s %(name)-15s %(message)s'
+ datefmt: '%Y-%m-%d %H:%M:%S'
+ custom:
+ (): my.package.customFormatterFactory
+ bar: baz
+ spam: 99.9
+ answer: 42
+
+The above YAML snippet defines three formatters. The first, with id
+``brief``, is a standard :class:`logging.Formatter` instance with the
+specified format string. The second, with id ``default``, has a
+longer format and also defines the time format explicitly, and will
+result in a :class:`logging.Formatter` initialized with those two format
+strings. Shown in Python source form, the ``brief`` and ``default``
+formatters have configuration sub-dictionaries::
+
+ {
+ 'format' : '%(message)s'
+ }
+
+and::
+
+ {
+ 'format' : '%(asctime)s %(levelname)-8s %(name)-15s %(message)s',
+ 'datefmt' : '%Y-%m-%d %H:%M:%S'
+ }
+
+respectively, and as these dictionaries do not contain the special key
+``'()'``, the instantiation is inferred from the context: as a result,
+standard :class:`logging.Formatter` instances are created. The
+configuration sub-dictionary for the third formatter, with id
+``custom``, is::
+
+ {
+ '()' : 'my.package.customFormatterFactory',
+ 'bar' : 'baz',
+ 'spam' : 99.9,
+ 'answer' : 42
+ }
+
+and this contains the special key ``'()'``, which means that
+user-defined instantiation is wanted. In this case, the specified
+factory callable will be used. If it is an actual callable it will be
+used directly - otherwise, if you specify a string (as in the example)
+the actual callable will be located using normal import mechanisms.
+The callable will be called with the **remaining** items in the
+configuration sub-dictionary as keyword arguments. In the above
+example, the formatter with id ``custom`` will be assumed to be
+returned by the call::
+
+ my.package.customFormatterFactory(bar='baz', spam=99.9, answer=42)
+
+The key ``'()'`` has been used as the special key because it is not a
+valid keyword parameter name, and so will not clash with the names of
+the keyword arguments used in the call. The ``'()'`` also serves as a
+mnemonic that the corresponding value is a callable.
+
+
+.. _logging-config-dict-externalobj:
+
+Access to external objects
+""""""""""""""""""""""""""
+
+There are times where a configuration needs to refer to objects
+external to the configuration, for example ``sys.stderr``. If the
+configuration dict is constructed using Python code, this is
+straightforward, but a problem arises when the configuration is
+provided via a text file (e.g. JSON, YAML). In a text file, there is
+no standard way to distinguish ``sys.stderr`` from the literal string
+``'sys.stderr'``. To facilitate this distinction, the configuration
+system looks for certain special prefixes in string values and
+treat them specially. For example, if the literal string
+``'ext://sys.stderr'`` is provided as a value in the configuration,
+then the ``ext://`` will be stripped off and the remainder of the
+value processed using normal import mechanisms.
+
+The handling of such prefixes is done in a way analogous to protocol
+handling: there is a generic mechanism to look for prefixes which
+match the regular expression ``^(?P<prefix>[a-z]+)://(?P<suffix>.*)$``
+whereby, if the ``prefix`` is recognised, the ``suffix`` is processed
+in a prefix-dependent manner and the result of the processing replaces
+the string value. If the prefix is not recognised, then the string
+value will be left as-is.
+
+
+.. _logging-config-dict-internalobj:
+
+Access to internal objects
+""""""""""""""""""""""""""
+
+As well as external objects, there is sometimes also a need to refer
+to objects in the configuration. This will be done implicitly by the
+configuration system for things that it knows about. For example, the
+string value ``'DEBUG'`` for a ``level`` in a logger or handler will
+automatically be converted to the value ``logging.DEBUG``, and the
+``handlers``, ``filters`` and ``formatter`` entries will take an
+object id and resolve to the appropriate destination object.
+
+However, a more generic mechanism is needed for user-defined
+objects which are not known to the :mod:`logging` module. For
+example, consider :class:`logging.handlers.MemoryHandler`, which takes
+a ``target`` argument which is another handler to delegate to. Since
+the system already knows about this class, then in the configuration,
+the given ``target`` just needs to be the object id of the relevant
+target handler, and the system will resolve to the handler from the
+id. If, however, a user defines a ``my.package.MyHandler`` which has
+an ``alternate`` handler, the configuration system would not know that
+the ``alternate`` referred to a handler. To cater for this, a generic
+resolution system allows the user to specify::
+
+ handlers:
+ file:
+ # configuration of file handler goes here
+
+ custom:
+ (): my.package.MyHandler
+ alternate: cfg://handlers.file
+
+The literal string ``'cfg://handlers.file'`` will be resolved in an
+analogous way to strings with the ``ext://`` prefix, but looking
+in the configuration itself rather than the import namespace. The
+mechanism allows access by dot or by index, in a similar way to
+that provided by ``str.format``. Thus, given the following snippet::
+
+ handlers:
+ email:
+ class: logging.handlers.SMTPHandler
+ mailhost: localhost
+ fromaddr: my_app@domain.tld
+ toaddrs:
+ - support_team@domain.tld
+ - dev_team@domain.tld
+ subject: Houston, we have a problem.
+
+in the configuration, the string ``'cfg://handlers'`` would resolve to
+the dict with key ``handlers``, the string ``'cfg://handlers.email``
+would resolve to the dict with key ``email`` in the ``handlers`` dict,
+and so on. The string ``'cfg://handlers.email.toaddrs[1]`` would
+resolve to ``'dev_team.domain.tld'`` and the string
+``'cfg://handlers.email.toaddrs[0]'`` would resolve to the value
+``'support_team@domain.tld'``. The ``subject`` value could be accessed
+using either ``'cfg://handlers.email.subject'`` or, equivalently,
+``'cfg://handlers.email[subject]'``. The latter form only needs to be
+used if the key contains spaces or non-alphanumeric characters. If an
+index value consists only of decimal digits, access will be attempted
+using the corresponding integer value, falling back to the string
+value if needed.
+
+Given a string ``cfg://handlers.myhandler.mykey.123``, this will
+resolve to ``config_dict['handlers']['myhandler']['mykey']['123']``.
+If the string is specified as ``cfg://handlers.myhandler.mykey[123]``,
+the system will attempt to retrieve the value from
+``config_dict['handlers']['myhandler']['mykey'][123]``, and fall back
+to ``config_dict['handlers']['myhandler']['mykey']['123']`` if that
+fails.
+
.. _logging-config-fileformat:
Configuration file format
:Release: |release|
:Date: |today|
-.. Fix accents on Kristjan Valur Jonsson, Fuerstenau
-
-.. Big jobs: ElementTree 1.3, pep 391, sysconfig
-.. unittest test discovery
.. hyperlink all the methods & functions.
+.. T_STRING_INPLACE not described in main docs
+.. "Format String Syntax" in string.rst could use many more examples.
+
.. $Id$
Rules for maintenance:
when researching a change.
This article explains the new features in Python 2.7. The final
-release of 2.7 is currently scheduled for June 2010; the detailed
+release of 2.7 is currently scheduled for July 2010; the detailed
schedule is described in :pep:`373`.
-Python 2.7 is planned to be the last major release in the 2.x series.
-Though more major releases have not been absolutely ruled out, the
-Python maintainers are planning to focus more on Python 3.x. Despite
-that, it's likely that the 2.7 release will have a longer period of
-maintenance compared to earlier 2.x versions.
-
-.. Compare with previous release in 2 - 3 sentences here.
- add hyperlink when the documentation becomes available online.
+Numeric handling has been improved in many ways, for both
+floating-point numbers and for the :class:`Decimal` class. There are
+some useful additions to the standard library, such as a greatly
+enhanced :mod:`unittest` module, the :mod:`argparse` module for
+parsing command-line options, convenient ordered-dictionary and
+:class:`Counter` classes in the :mod:`collections` module, and many
+other improvements.
+
+Python 2.7 is planned to be the last of the 2.x releases, so we worked
+on making it a good release for the long term. To help with porting
+to Python 3, several new features from the Python 3.x series have been
+included in 2.7.
+
+This article doesn't attempt to provide a complete specification of
+the new features, but instead provides a convenient overview. For
+full details, you should refer to the documentation for Python 2.7 at
+http://docs.python.org. If you want to understand the rationale for
+the design and implementation, refer to the PEP for a particular new
+feature or the issue on http://bugs.python.org in which a change was
+discussed. Whenever possible, "What's New in Python" links to the
+bug/patch item for each change.
.. _whatsnew27-python31:
+The Future for Python 2.x
+=========================
+
+Python 2.7 is intended to be the last major release in the 2.x series.
+The Python maintainers are planning to focus their future efforts on
+the Python 3.x series.
+
+This means that 2.7 will remain in place for a long time, running
+production systems that have not been ported to Python 3.x.
+Two consequences of the long-term significance of 2.7 are:
+
+* It's very likely the 2.7 release will have a longer period of
+ maintenance compared to earlier 2.x versions. Python 2.7 will
+ continue to be maintained while the transition to 3.x continues, and
+ the developers are planning to support Python 2.7 with bug-fix
+ releases beyond the typical two years.
+
+* A policy decision was made to silence warnings only of interest to
+ developers. :exc:`DeprecationWarning` and its
+ descendants are now ignored unless otherwise requested, preventing
+ users from seeing warnings triggered by an application. This change
+ was also made in the branch that will become Python 3.2. (Discussed
+ on stdlib-sig and carried out in :issue:`7319`.)
+
+ In previous releases, :exc:`DeprecationWarning` messages were
+ enabled by default, providing Python developers with a clear
+ indication of where their code may break in a future major version
+ of Python.
+
+ However, there are increasingly many users of Python-based
+ applications who are not directly involved in the development of
+ those applications. :exc:`DeprecationWarning` messages are
+ irrelevant to such users, making them worry about an application
+ that's actually working correctly and burdening application developers
+ with responding to these concerns.
+
+ You can re-enable display of :exc:`DeprecationWarning` messages by
+ running Python with the :option:`-Wdefault` (short form:
+ :option:`-Wd`) switch, or by setting the :envvar:`PYTHONWARNINGS`
+ environment variable to ``"default"`` (or ``"d"``) before running
+ Python. Python code can also re-enable them
+ by calling ``warnings.simplefilter('default')``.
+
+
Python 3.1 Features
=======================
A partial list of 3.1 features that were backported to 2.7:
-* A version of the :mod:`io` library, rewritten in C for performance.
+* The syntax for set literals (``{1,2,3}`` is a mutable set).
+* Dictionary and set comprehensions (``{ i: i*2 for i in range(3)}``).
+* Multiple context managers in a single :keyword:`with` statement.
+* A new version of the :mod:`io` library, rewritten in C for performance.
* The ordered-dictionary type described in :ref:`pep-0372`.
-* The new format specifier described in :ref:`pep-0378`.
+* The new ``","`` format specifier described in :ref:`pep-0378`.
* The :class:`memoryview` object.
-* A small subset of the :mod:`importlib` module `described below <#importlib-section>`__.
+* A small subset of the :mod:`importlib` module,
+ `described below <#importlib-section>`__.
* Float-to-string and string-to-float conversions now round their
- results more correctly. And :func:`repr` of a floating-point
+ results more correctly, and :func:`repr` of a floating-point
number *x* returns a result that's guaranteed to round back to the
same number when converted back to a string.
+* The :ctype:`PyCapsule` type, used to provide a C API for extension modules.
* The :cfunc:`PyLong_AsLongAndOverflow` C API function.
-One porting change: the :option:`-3` switch now automatically
-enables the :option:`-Qwarn` switch that causes warnings
-about using classic division with integers and long integers.
-
Other new Python3-mode warnings include:
* :func:`operator.isCallable` and :func:`operator.sequenceIncludes`,
- which are not supported in 3.x.
+ which are not supported in 3.x, now trigger warnings.
+* The :option:`-3` switch now automatically
+ enables the :option:`-Qwarn` switch that causes warnings
+ about using classic division with integers and long integers.
+
+
.. ========================================================================
.. Large, PEP-level features and changes should be described here.
.. _pep-0372:
-PEP 372: Adding an ordered dictionary to collections
+PEP 372: Adding an Ordered Dictionary to collections
====================================================
Regular Python dictionaries iterate over key/value pairs in arbitrary order.
Over the years, a number of authors have written alternative implementations
that remember the order that the keys were originally inserted. Based on
-the experiences from those implementations, a new
-:class:`~collections.OrderedDict` class has been introduced in the
-:mod:`collections` module.
+the experiences from those implementations, 2.7 introduces a new
+:class:`~collections.OrderedDict` class in the :mod:`collections` module.
-The :class:`~collections.OrderedDict` API is substantially the same as regular
-dictionaries but will iterate over keys and values in a guaranteed order
+The :class:`~collections.OrderedDict` API provides the same interface as regular
+dictionaries but iterates over keys and values in a guaranteed order
depending on when a key was first inserted::
>>> from collections import OrderedDict
- >>> d = OrderedDict([('first', 1), ('second', 2),
+ >>> d = OrderedDict([('first', 1),
+ ... ('second', 2),
... ('third', 3)])
>>> d.items()
[('first', 1), ('second', 2), ('third', 3)]
Comparing two ordered dictionaries checks both the keys and values,
and requires that the insertion order was the same::
- >>> od1 = OrderedDict([('first', 1), ('second', 2),
+ >>> od1 = OrderedDict([('first', 1),
+ ... ('second', 2),
... ('third', 3)])
- >>> od2 = OrderedDict([('third', 3), ('first', 1),
+ >>> od2 = OrderedDict([('third', 3),
+ ... ('first', 1),
... ('second', 2)])
>>> od1 == od2
False
deletion doesn't have to traverse the entire linked list and therefore
remains O(1).
-.. XXX check O(1)-ness with Raymond
-.. Also check if the 'somenamedtuple' in the collection module should
-.. be replaced/removed in order to use
-.. :meth:`~collections.namedtuple._asdict()` (see below)
-
The standard library now supports use of ordered dictionaries in several
modules.
-* The :mod:`ConfigParser` module uses them by default, letting
- configuration files be read, modified, and then written back in their original
- order.
+* The :mod:`ConfigParser` module uses them by default, meaning that
+ configuration files can now read, modified, and then written back
+ in their original order.
* The :meth:`~collections.somenamedtuple._asdict()` method for
:func:`collections.namedtuple` now returns an ordered dictionary with the
=================================================
To make program output more readable, it can be useful to add
-separators to large numbers and render them as
+separators to large numbers, rendering them as
18,446,744,073,709,551,616 instead of 18446744073709551616.
The fully general solution for doing this is the :mod:`locale` module,
comma-formatting mechanism isn't as general as the :mod:`locale`
module, but it's easier to use.
-.. XXX "Format String Syntax" in string.rst could use many more examples.
-
.. seealso::
:pep:`378` - Format Specifier for Thousands Separator
======================================================
The :mod:`argparse` module for parsing command-line arguments was
-added, intended as a more powerful replacement for the
+added as a more powerful replacement for the
:mod:`optparse` module.
This means Python now supports three different modules for parsing
command-line arguments: :mod:`getopt`, :mod:`optparse`, and
:mod:`argparse`. The :mod:`getopt` module closely resembles the C
-:cfunc:`getopt` function, so it remains useful if you're writing a
+library's :cfunc:`getopt` function, so it remains useful if you're writing a
Python prototype that will eventually be rewritten in C.
:mod:`optparse` becomes redundant, but there are no plans to remove it
because there are many scripts still using it, and there's no
-o FILE direct output to FILE instead of stdout
-C NUM display NUM lines of added context
-Similarly to :mod:`optparse`, the command-line switches and arguments
+As with :mod:`optparse`, the command-line switches and arguments
are returned as an object with attributes named by the *dest* parameters::
-> ./python.exe argparse-example.py -v
- {'output': None, 'is_verbose': True, 'context': 0, 'inputs': []}
+ {'output': None,
+ 'is_verbose': True,
+ 'context': 0,
+ 'inputs': []}
-> ./python.exe argparse-example.py -v -o /tmp/output -C 4 file1 file2
- {'output': '/tmp/output', 'is_verbose': True, 'context': 4,
+ {'output': '/tmp/output',
+ 'is_verbose': True,
+ 'context': 4,
'inputs': ['file1', 'file2']}
:mod:`argparse` has much fancier validation than :mod:`optparse`; you
can specify an exact number of arguments as an integer, 0 or more
arguments by passing ``'*'``, 1 or more by passing ``'+'``, or an
optional argument with ``'?'``. A top-level parser can contain
-sub-parsers, so you can define subcommands that have different sets of
+sub-parsers to define subcommands that have different sets of
switches, as in ``svn commit``, ``svn checkout``, etc. You can
-specify an argument type as :class:`~argparse.FileType`, which will
+specify an argument's type as :class:`~argparse.FileType`, which will
automatically open files for you and understands that ``'-'`` means
standard input or output.
`argparse module documentation <http://docs.python.org/dev/library/argparse.html>`__
`Upgrading optparse code to use argparse <http://docs.python.org/dev/library/argparse.html#upgrading-optparse-code>`__
+ Part of the Python documentation, describing how to convert
+ code that uses :mod:`optparse`.
:pep:`389` - argparse - New Command Line Parsing Module
PEP written and implemented by Steven Bethard.
PEP 391: Dictionary-Based Configuration For Logging
====================================================
-.. not documented in library reference yet.
+.. XXX not documented in library reference yet; add link here once it's added.
-The :mod:`logging` module is very flexible; an application can define
+The :mod:`logging` module is very flexible; applications can define
a tree of logging subsystems, and each logger in this tree can filter
out certain messages, format them differently, and direct messages to
a varying number of handlers.
All this flexibility can require a lot of configuration. You can
write Python statements to create objects and set their properties,
-but a complex set-up would require verbose but boring code.
+but a complex set-up requires verbose but boring code.
:mod:`logging` also supports a :func:`~logging.config.fileConfig`
function that parses a file, but the file format doesn't support
configuring filters, and it's messier to generate programmatically.
Python 2.7 adds a :func:`~logging.config.dictConfig` function that
-uses a dictionary, and there are many ways to produce a dictionary
-from different sources. You can construct one with code, of course.
-Python's standard library now includes a JSON parser, so you could
-parse a file containing JSON, or you could use a YAML parsing library
-if one is installed.
+uses a dictionary to configure logging. There are many ways to
+produce a dictionary from different sources: construct one with code;
+parse a file containing JSON; or use a YAML parsing library if one is
+installed.
-XXX describe an example.
+The following example configures two loggers, the root logger and a
+logger named "network". Messages sent to the root logger will be
+sent to the system log using the syslog protocol, and messages
+to the "network" logger will be written to a :file:`network.log` file
+that will be rotated once the log reaches 1Mb.
-Two smaller enhancements to the logging module are:
+::
+
+ import logging
+ import logging.config
+
+ configdict = {
+ 'version': 1, # Configuration schema in use; must be 1 for now
+ 'formatters': {
+ 'standard': {
+ 'format': ('%(asctime)s %(name)-15s '
+ '%(levelname)-8s %(message)s')}},
+
+ 'handlers': {'netlog': {'backupCount': 10,
+ 'class': 'logging.handlers.RotatingFileHandler',
+ 'filename': '/logs/network.log',
+ 'formatter': 'standard',
+ 'level': 'INFO',
+ 'maxBytes': 1024*1024},
+ 'syslog': {'class': 'logging.handlers.SysLogHandler',
+ 'formatter': 'standard',
+ 'level': 'ERROR'}},
+
+ # Specify all the subordinate loggers
+ 'loggers': {
+ 'network': {
+ 'handlers': ['netlog']
+ }
+ },
+ # Specify properties of the root logger
+ 'root': {
+ 'handlers': ['syslog']
+ },
+ }
+
+ # Set up configuration
+ logging.config.dictConfig(configdict)
+
+ # As an example, log two error messages
+ logger = logging.getLogger('/')
+ logger.error('Database not found')
+
+ netlogger = logging.getLogger('network')
+ netlogger.error('Connection failed')
+
+Three smaller enhancements to the :mod:`logging` module, all
+implemented by Vinay Sajip, are:
.. rev79293
-* :class:`Logger` instances gained a :meth:`getChild` that retrieves a
+* The :class:`~logging.handlers.SysLogHandler` class now supports
+ syslogging over TCP. The constructor has a *socktype* parameter
+ giving the type of socket to use, either :const:`socket.SOCK_DGRAM`
+ for UDP or :const:`socket.SOCK_STREAM` for TCP. The default
+ protocol remains UDP.
+
+* :class:`Logger` instances gained a :meth:`getChild` method that retrieves a
descendant logger using a relative path. For example,
once you retrieve a logger by doing ``log = getLogger('app')``,
calling ``log.getChild('network.listen')`` is equivalent to
are different in Python 3.x. They return an object called a :dfn:`view`
instead of a fully materialized list.
-.. Views can be iterated over, but they also behave like sets. XXX not working.
-
It's not possible to change the return values of :meth:`keys`,
:meth:`values`, and :meth:`items` in Python 2.7 because too much code
would break. Instead the 3.x versions were added under the new names
-of :meth:`viewkeys`, :meth:`viewvalues`, and :meth:`viewitems`.
+:meth:`viewkeys`, :meth:`viewvalues`, and :meth:`viewitems`.
::
>>> d.viewkeys()
dict_keys([0, 130, 10, 140, 20, 150, 30, ..., 250])
+Views can be iterated over, but the key and item views also behave
+like sets. The ``&`` operator performs intersection, and ``|``
+performs a union::
+
+ >>> d1 = dict((i*10, chr(65+i)) for i in range(26))
+ >>> d2 = dict((i**.5, i) for i in range(1000))
+ >>> d1.viewkeys() & d2.viewkeys()
+ set([0.0, 10.0, 20.0, 30.0])
+ >>> d1.viewkeys() | range(0, 30)
+ set([0, 1, 130, 3, 4, 5, 6, ..., 120, 250])
+
The view keeps track of the dictionary and its contents change as the
dictionary is modified::
Backported to 2.7 by Alexandre Vassalotti; :issue:`1967`.
+PEP 3137: The memoryview Object
+====================================================
+
+The :class:`memoryview` object provides a view of another object's
+memory content that matches the :class:`bytes` type's interface.
+
+ >>> import string
+ >>> m = memoryview(string.letters)
+ >>> m
+ <memory at 0x37f850>
+ >>> len(m) # Returns length of underlying object
+ 52
+ >>> m[0], m[25], m[26] # Indexing returns one byte
+ ('a', 'z', 'A')
+ >>> m2 = m[0:26] # Slicing returns another memoryview
+ >>> m2
+ <memory at 0x37f080>
+
+The content of the view can be converted to a string of bytes or
+a list of integers:
+
+ >>> m2.tobytes()
+ 'abcdefghijklmnopqrstuvwxyz'
+ >>> m2.tolist()
+ [97, 98, 99, 100, 101, 102, 103, ... 121, 122]
+ >>>
+
+:class:`memoryview` objects allow modifying the underlying object if
+it's a mutable object.
+
+ >>> m2[0] = 75
+ Traceback (most recent call last):
+ File "<stdin>", line 1, in <module>
+ TypeError: cannot modify read-only memory
+ >>> b = bytearray(string.letters) # Creating a mutable object
+ >>> b
+ bytearray(b'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ')
+ >>> mb = memoryview(b)
+ >>> mb[0] = '*' # Assign to view, changing the bytearray.
+ >>> b[0:5] # The bytearray has been changed.
+ bytearray(b'*bcde')
+ >>>
+
+.. seealso::
+
+ :pep:`3137` - Immutable Bytes and Mutable Buffer
+ PEP written by Guido van Rossum.
+ Implemented by Travis Oliphant, Antoine Pitrou and others.
+ Backported to 2.7 by Antoine Pitrou; :issue:`2396`.
+
+
+
Other Language Changes
======================
3.x, generalizing list/generator comprehensions to use
the literal syntax for sets and dictionaries.
- >>> {x:x*x for x in range(6)}
+ >>> {x: x*x for x in range(6)}
{0: 0, 1: 1, 2: 4, 3: 9, 4: 16, 5: 25}
- >>> {'a'*x for x in range(6)}
+ >>> {('a'*x) for x in range(6)}
set(['', 'a', 'aa', 'aaa', 'aaaa', 'aaaaa'])
Backported by Alexandre Vassalotti; :issue:`2333`.
in many different places: :func:`str` on
floats and complex numbers; the :class:`float` and :class:`complex`
constructors;
- numeric formatting; serialization and
- deserialization of floats and complex numbers using the
+ numeric formatting; serializing and
+ deserializing floats and complex numbers using the
:mod:`marshal`, :mod:`pickle`
and :mod:`json` modules;
parsing of float and imaginary literals in Python code;
.. maybe add an example?
The rounding library responsible for this improvement works on
- Windows, and on Unix platforms using the gcc, icc, or suncc
+ Windows and on Unix platforms using the gcc, icc, or suncc
compilers. There may be a small number of platforms where correct
operation of this code cannot be guaranteed, so the code is not
used on such systems. You can find out which code is being used
Implemented by Eric Smith and Mark Dickinson, using David Gay's
:file:`dtoa.c` library; :issue:`7117`.
+* Conversions from long integers and regular integers to floating
+ point now round differently, returning the floating-point number
+ closest to the number. This doesn't matter for small integers that
+ can be converted exactly, but for large numbers that will
+ unavoidably lose precision, Python 2.7 now approximates more
+ closely. For example, Python 2.6 computed the following::
+
+ >>> n = 295147905179352891391
+ >>> float(n)
+ 2.9514790517935283e+20
+ >>> n - long(float(n))
+ 65535L
+
+ Python 2.7's floating-point result is larger, but much closer to the
+ true value::
+
+ >>> n = 295147905179352891391
+ >>> float(n)
+ 2.9514790517935289e+20
+ >>> n - long(float(n))
+ -1L
+
+ (Implemented by Mark Dickinson; :issue:`3166`.)
+
+ Integer division is also more accurate in its rounding behaviours. (Also
+ implemented by Mark Dickinson; :issue:`1811`.)
+
+* Implicit coercion for complex numbers has been removed; the interpreter
+ will no longer ever attempt to call a :meth:`__coerce__` method on complex
+ objects. (Removed by Meador Inge and Mark Dickinson; :issue:`5211`.)
+
* The :meth:`str.format` method now supports automatic numbering of the replacement
fields. This makes using :meth:`str.format` more closely resemble using
``%s`` formatting::
so it will now produce 'INF' and 'NAN'.
(Contributed by Eric Smith; :issue:`3382`.)
+ A low-level change: the :meth:`object.__format__` method now triggers
+ a :exc:`PendingDeprecationWarning` if it's passed a format string,
+ because the :meth:`__format__` method for :class:`object` converts
+ the object to a string representation and formats that. Previously
+ the method silently applied the format string to the string
+ representation, but that could hide mistakes in Python code. If
+ you're supplying formatting information such as an alignment or
+ precision, presumably you're expecting the formatting to be applied
+ in some object-specific way. (Fixed by Eric Smith; :issue:`7994`.)
+
* The :func:`int` and :func:`long` types gained a ``bit_length``
method that returns the number of bits necessary to represent
its argument in binary::
(Contributed by Fredrik Johansson and Victor Stinner; :issue:`3439`.)
-* Conversions from long integers and regular integers to floating
- point now round differently, returning the floating-point number
- closest to the number. This doesn't matter for small integers that
- can be converted exactly, but for large numbers that will
- unavoidably lose precision, Python 2.7 now approximates more
- closely. For example, Python 2.6 computed the following::
-
- >>> n = 295147905179352891391
- >>> float(n)
- 2.9514790517935283e+20
- >>> n - long(float(n))
- 65535L
-
- Python 2.7's floating-point result is larger, but much closer to the
- true value::
-
- >>> n = 295147905179352891391
- >>> float(n)
- 2.9514790517935289e+20
- >>> n - long(float(n))
- -1L
-
- (Implemented by Mark Dickinson; :issue:`3166`.)
-
- Integer division is also more accurate in its rounding behaviours. (Also
- implemented by Mark Dickinson; :issue:`1811`.)
+* The :keyword:`import` statement will no longer try a relative import
+ if an absolute import (e.g. ``from .os import sep``) fails. This
+ fixes a bug, but could possibly break certain :keyword:`import`
+ statements that were only working by accident. (Fixed by Meador Inge;
+ :issue:`7902`.)
* It's now possible for a subclass of the built-in :class:`unicode` type
to override the :meth:`__unicode__` method. (Implemented by
(Contributed by Amaury Forgeot d'Arc, after a suggestion by
George Sakkis; :issue:`5982`.)
-* A new encoding named "cp720", used primarily for Arabic text, is now
- supported. (Contributed by Alexander Belchenko and Amaury Forgeot
- d'Arc; :issue:`1616979`.)
+* When a restricted set of attributes were set using ``__slots__``,
+ deleting an unset attribute would not raise :exc:`AttributeError`
+ as you would expect. Fixed by Benjamin Peterson; :issue:`7604`.)
+
+* Two new encodings are now supported: "cp720", used primarily for
+ Arabic text; and "cp858", a variant of CP 850 that adds the euro
+ symbol. (CP720 contributed by Alexander Belchenko and Amaury
+ Forgeot d'Arc in :issue:`1616979`; CP858 contributed by Tim Hatch in
+ :issue:`8016`.)
* The :class:`file` object will now set the :attr:`filename` attribute
on the :exc:`IOError` exception when trying to open a directory
(fixed by Stefan Krah; :issue:`5677`).
* The Python tokenizer now translates line endings itself, so the
- :func:`compile` built-in function can now accept code using any
+ :func:`compile` built-in function now accepts code using any
line-ending convention. Additionally, it no longer requires that the
code end in a newline.
For example, the following setting will print warnings every time
they occur, but turn warnings from the :mod:`Cookie` module into an
error. (The exact syntax for setting an environment variable varies
-across operating systems and shells, so it may be different for you.)
+across operating systems and shells.)
::
export PYTHONWARNINGS=all,error:::Cookie:0
+When running a module using the interpreter's :option:`-m` switch,
+``sys.argv[0]`` will now be set to the string ``'-m'`` while the
+module is being located, while executing the :file:`__init__.py` files
+for any parent packages of the module to be executed.
+(Suggested by Michael Foord; implemented by Nick Coghlan;
+:issue:`8202`.)
.. ======================================================================
any of them. This would previously take quadratic
time for garbage collection, but now the number of full garbage collections
is reduced as the number of objects on the heap grows.
- The new logic is to only perform a full garbage collection pass when
+ The new logic only performs a full garbage collection pass when
the middle generation has been collected 10 times and when the
number of survivor objects from the middle generation exceeds 10% of
the number of objects in the oldest generation. (Suggested by Martin
The new version features better Python 3.x compatibility, various bug fixes,
and adds several new BerkeleyDB flags and methods.
(Updated by Jesús Cea Avión; :issue:`8156`. The pybsddb
- changelog can be browsed at http://hg.jcea.es/pybsddb/file/tip/ChangeLog.)
+ changelog can be read at http://hg.jcea.es/pybsddb/file/tip/ChangeLog.)
* The :mod:`bz2` module's :class:`~bz2.BZ2File` now supports the context
- management protocol, so you can write ``with bz2.BZ2File(...) as f: ...``.
- (Contributed by Hagen Fuerstenau; :issue:`3860`.)
+ management protocol, so you can write ``with bz2.BZ2File(...) as f:``.
+ (Contributed by Hagen Fürstenau; :issue:`3860`.)
* New class: the :class:`~collections.Counter` class in the :mod:`collections`
module is useful for tallying data. :class:`~collections.Counter` instances
>>> c['z']
0
- There are three additional :class:`~collections.Counter` methods:
+ There are three additional :class:`~collections.Counter` methods.
:meth:`~collections.Counter.most_common` returns the N most common
elements and their counts. :meth:`~collections.Counter.elements`
returns an iterator over the contained elements, repeating each
.. revision 79660
- The new :class:`~collections.OrderedDict` class is described in the earlier
+ New class: :class:`~collections.OrderedDict` is described in the earlier
section :ref:`pep-0372`.
+ New method: The :class:`~collections.deque` data type now has a
+ :meth:`~collections.deque.count` method that returns the number of
+ contained elements equal to the supplied argument *x*, and a
+ :meth:`~collections.deque.reverse` method that reverses the elements
+ of the deque in-place. :class:`deque` also exposes its maximum
+ length as the read-only :attr:`~collections.deque.maxlen` attribute.
+ (Both features added by Raymond Hettinger.)
+
The :class:`~collections.namedtuple` class now has an optional *rename* parameter.
If *rename* is true, field names that are invalid because they've
- been repeated or that aren't legal Python identifiers will be
+ been repeated or aren't legal Python identifiers will be
renamed to legal names that are derived from the field's
position within the list of fields:
(Added by Raymond Hettinger; :issue:`1818`.)
- The :class:`~collections.deque` data type now has a
- :meth:`~collections.deque.count` method that returns the number of
- contained elements equal to the supplied argument *x*, and a
- :meth:`~collections.deque.reverse` method that reverses the elements
- of the deque in-place. :class:`deque` also exposes its maximum
- length as the read-only :attr:`~collections.deque.maxlen` attribute.
- (Both features added by Raymond Hettinger.)
+ Finally, the :class:`~collections.Mapping` abstract base class now
+ raises a :exc:`NotImplemented` exception if a mapping is compared to
+ another type that isn't a :class:`Mapping`.
+ (Fixed by Daniel Stutzbach; :issue:`8729`.)
+
+* Constructors for the parsing classes in the :mod:`ConfigParser` module now
+ take a *allow_no_value* parameter, defaulting to false; if true,
+ options without values will be allowed. For example::
+
+ >>> import ConfigParser, StringIO
+ >>> sample_config = """
+ ... [mysqld]
+ ... user = mysql
+ ... pid-file = /var/run/mysqld/mysqld.pid
+ ... skip-bdb
+ ... """
+ >>> config = ConfigParser.RawConfigParser(allow_no_value=True)
+ >>> config.readfp(StringIO.StringIO(sample_config))
+ >>> config.get('mysqld', 'user')
+ 'mysql'
+ >>> print config.get('mysqld', 'skip-bdb')
+ None
+ >>> print config.get('mysqld', 'unknown')
+ Traceback (most recent call last):
+ ...
+ NoOptionError: No option 'unknown' in section: 'mysqld'
+
+ (Contributed by Mats Kindahl; :issue:`7005`.)
+
+* Deprecated function: :func:`contextlib.nested`, which allows
+ handling more than one context manager with a single :keyword:`with`
+ statement, has been deprecated, because the :keyword:`with` statement
+ now supports multiple context managers.
+
+* The :mod:`cookielib` module now ignores cookies that have an invalid
+ version field, one that doesn't contain an integer value. (Fixed by
+ John J. Lee; :issue:`3924`.)
* The :mod:`copy` module's :func:`~copy.deepcopy` function will now
correctly copy bound instance methods. (Implemented by
* New method: the :class:`~decimal.Decimal` class gained a
:meth:`~decimal.Decimal.from_float` class method that performs an exact
conversion of a floating-point number to a :class:`~decimal.Decimal`.
- Note that this is an **exact** conversion that strives for the
+ This exact conversion strives for the
closest decimal approximation to the floating-point representation's value;
the resulting decimal value will therefore still include the inaccuracy,
if any.
``Decimal('0.1000000000000000055511151231257827021181583404541015625')``.
(Implemented by Raymond Hettinger; :issue:`4796`.)
- Most of the methods of the :class:`~decimal.Context` class now accept integers
- as well as :class:`~decimal.Decimal` instances; the only exceptions are the
- :meth:`~decimal.Context.canonical` and :meth:`~decimal.Context.is_canonical`
- methods. (Patch by Juan José Conti; :issue:`7633`.)
+ Comparing instances of :class:`Decimal` with floating-point
+ numbers now produces sensible results based on the numeric values
+ of the operands. Previously such comparisons would fall back to
+ Python's default rules for comparing objects, which produced arbitrary
+ results based on their type. Note that you still cannot combine
+ :class:`Decimal` and floating-point in other operations such as addition,
+ since you should be explicitly choosing how to convert between float and
+ :class:`Decimal`.
+ (Fixed by Mark Dickinson; :issue:`2531`.)
The constructor for :class:`~decimal.Decimal` now accepts
floating-point numbers (added by Raymond Hettinger; :issue:`8257`)
and non-European Unicode characters such as Arabic-Indic digits
(contributed by Mark Dickinson; :issue:`6595`).
+ Most of the methods of the :class:`~decimal.Context` class now accept integers
+ as well as :class:`~decimal.Decimal` instances; the only exceptions are the
+ :meth:`~decimal.Context.canonical` and :meth:`~decimal.Context.is_canonical`
+ methods. (Patch by Juan José Conti; :issue:`7633`.)
+
When using :class:`~decimal.Decimal` instances with a string's
:meth:`~str.format` method, the default alignment was previously
- left-alignment. This has been changed to right-alignment, which seems
+ left-alignment. This has been changed to right-alignment, which is
more sensible for numeric types. (Changed by Mark Dickinson; :issue:`6857`.)
+ Comparisons involving a signaling NaN value (or ``sNAN``) now signal
+ :const:`InvalidOperation` instead of silently returning a true or
+ false value depending on the comparison operator. Quiet NaN values
+ (or ``NaN``) are now hashable. (Fixed by Mark Dickinson;
+ :issue:`7279`.)
+
* The :mod:`difflib` module now produces output that is more
- compatible with modern :command:`diff`/:command:`patch` tools thanks
- to two changes: 1) the header giving the filename now uses a tab
- character instead of spaces as a separator, and 2) the date format
- used is now ISO-8601 style, ``2005-01-26 23:30:50``. (Fixed by
- Anatoly Techtonik; :issue:`7585`.)
+ compatible with modern :command:`diff`/:command:`patch` tools
+ through one small change, using a tab character instead of spaces as
+ a separator in the header giving the filename. (Fixed by Anatoly
+ Techtonik; :issue:`7585`.)
+
+* The Distutils ``sdist`` command now always regenerates the
+ :file:`MANIFEST` file, since even if the :file:`MANIFEST.in` or
+ :file:`setup.py` files haven't been modified, the user might have
+ created some new files that should be included.
+ (Fixed by Tarek Ziadé; :issue:`8688`.)
+
+* The :mod:`doctest` module's :const:`IGNORE_EXCEPTION_DETAIL` flag
+ will now ignore the name of the module containing the exception
+ being tested. (Patch by Lennart Regebro; :issue:`7490`.)
+
+* The :mod:`email` module's :class:`~email.message.Message` class will
+ now accept a Unicode-valued payload, automatically converting the
+ payload to the encoding specified by :attr:`output_charset`.
+ (Added by R. David Murray; :issue:`1368247`.)
* The :class:`~fractions.Fraction` class now accepts a single float or
:class:`~decimal.Decimal` instance, or two rational numbers, as
rationals added in :issue:`5812`, and float/decimal in
:issue:`8294`.)
- An oversight was fixed, making the :class:`Fraction` match the other
- numeric types; ordering comparisons (``<``, ``<=``, ``>``, ``>=``) between
+ Ordering comparisons (``<``, ``<=``, ``>``, ``>=``) between
fractions and complex numbers now raise a :exc:`TypeError`.
+ This fixes an oversight, making the :class:`Fraction` match the other
+ numeric types.
.. revision 79455
-* New class: a new :class:`~ftplib.FTP_TLS` class in
+* New class: :class:`~ftplib.FTP_TLS` in
the :mod:`ftplib` module provides secure FTP
connections using TLS encapsulation of authentication as well as
subsequent control and data transfers.
- (Contributed by Giampaolo Rodola', :issue:`2054`.)
+ (Contributed by Giampaolo Rodola; :issue:`2054`.)
The :meth:`~ftplib.FTP.storbinary` method for binary uploads can now restart
uploads thanks to an added *rest* parameter (patch by Pablo Mouzo;
otherwise. (Contributed by Antoine Pitrou; :issue:`4688`.)
* The :mod:`gzip` module's :class:`~gzip.GzipFile` now supports the context
- management protocol, so you can write ``with gzip.GzipFile(...) as f: ...``
- (contributed by Hagen Fuerstenau; :issue:`3860`), and it now implements
+ management protocol, so you can write ``with gzip.GzipFile(...) as f:``
+ (contributed by Hagen Fürstenau; :issue:`3860`), and it now implements
the :class:`io.BufferedIOBase` ABC, so you can wrap it with
:class:`io.BufferedReader` for faster processing
(contributed by Nir Aides; :issue:`7471`).
* New attribute: the :mod:`hashlib` module now has an :attr:`~hashlib.hashlib.algorithms`
attribute containing a tuple naming the supported algorithms.
In Python 2.7, ``hashlib.algorithms`` contains
- ``('md5', 'sha1', 'sha224', 'sha256', 'sha384', 'sha512')``
+ ``('md5', 'sha1', 'sha224', 'sha256', 'sha384', 'sha512')``.
(Contributed by Carl Chenet; :issue:`7418`.)
* The default :class:`~httplib.HTTPResponse` class used by the :mod:`httplib` module now
supports buffering, resulting in much faster reading of HTTP responses.
- (Contributed by Kristjan Valur Jonsson; :issue:`4879`.)
+ (Contributed by Kristján Valur Jónsson; :issue:`4879`.)
The :class:`~httplib.HTTPConnection` and :class:`~httplib.HTTPSConnection` classes
now support a *source_address* parameter, a ``(host, port)`` 2-tuple
giving the source address that will be used for the connection.
(Contributed by Eldon Ziegler; :issue:`3972`.)
+* The :mod:`ihooks` module now supports relative imports. Note that
+ :mod:`ihooks` is an older module for customizing imports,
+ superseded by the :mod:`imputil` module added in Python 2.0.
+ (Relative import support added by Neil Schemenauer.)
+
+ .. revision 75423
+
* The :mod:`imaplib` module now supports IPv6 addresses.
(Contributed by Derek Morr; :issue:`1655`.)
>>> def f(a, b=1, *pos, **named):
... pass
>>> getcallargs(f, 1, 2, 3)
- {'a': 1, 'named': {}, 'b': 2, 'pos': (3,)}
+ {'a': 1, 'b': 2, 'pos': (3,), 'named': {}}
>>> getcallargs(f, a=2, x=4)
- {'a': 2, 'named': {'x': 4}, 'b': 1, 'pos': ()}
+ {'a': 2, 'b': 1, 'pos': (), 'named': {'x': 4}}
>>> getcallargs(f)
Traceback (most recent call last):
...
floats or :class:`~decimal.Decimal` instances. (Implemented by Raymond
Hettinger; :issue:`5032`.)
- :func:`itertools.combinations` and :func:`itertools.product` were
- previously raising :exc:`ValueError` for values of *r* larger than
+ :func:`itertools.combinations` and :func:`itertools.product`
+ previously raised :exc:`ValueError` for values of *r* larger than
the input iterable. This was deemed a specification error, so they
now return an empty iterator. (Fixed by Raymond Hettinger; :issue:`4816`.)
with any object literal that decodes to a list of pairs.
(Contributed by Raymond Hettinger; :issue:`5381`.)
+* The :mod:`mailbox` module's :class:`Maildir` class now records the
+ timestamp on the directories it reads, and only re-reads them if the
+ modification time has subsequently changed. This improves
+ performance by avoiding unneeded directory scans. (Fixed by
+ A.M. Kuchling and Antoine Pitrou; :issue:`1607951`, :issue:`6896`.)
+
* New functions: the :mod:`math` module gained
:func:`~math.erf` and :func:`~math.erfc` for the error function and the complementary error function,
:func:`~math.expm1` which computes ``e**x - 1`` with more precision than
real, effective, and saved GIDs and UIDs;
:func:`~os.setresgid` and :func:`~os.setresuid`, which set
real, effective, and saved GIDs and UIDs to new values;
- :func:`~os.initgroups`. (GID/UID functions
+ :func:`~os.initgroups`, which initialize the group access list
+ for the current process. (GID/UID functions
contributed by Travis H.; :issue:`6508`. Support for initgroups added
by Jean-Paul Calderone; :issue:`7333`.)
now accept an optional *flags* argument, for consistency with the
other functions in the module. (Added by Gregory P. Smith.)
+* New function: :func:`~runpy.run_path` in the :mod:`runpy` module
+ will execute the code at a provided *path* argument. *path* can be
+ the path of a Python source file (:file:`example.py`), a compiled
+ bytecode file (:file:`example.pyc`), a directory
+ (:file:`./package/`), or a zip archive (:file:`example.zip`). If a
+ directory or zip path is provided, it will be added to the front of
+ ``sys.path`` and the module :mod:`__main__` will be imported. It's
+ expected that the directory or zip contains a :file:`__main__.py`;
+ if it doesn't, some other :file:`__main__.py` might be imported from
+ a location later in ``sys.path``. This makes some of the machinery
+ of :mod:`runpy` available to scripts that want to mimic the way
+ Python's :option:`-m` processes an explicit path name.
+ (Added by Nick Coghlan; :issue:`6816`.)
+
* New function: in the :mod:`shutil` module, :func:`~shutil.make_archive`
takes a filename, archive type (zip or tar-format), and a directory
path, and creates an archive containing the directory's contents.
named pipes like a regular file by opening them for reading, and
this would block indefinitely. (Fixed by Antoine Pitrou; :issue:`3002`.)
+* The :mod:`signal` module no longer re-installs the signal handler
+ unless this is truly necessary, which fixes a bug that could make it
+ impossible to catch the EINTR signal robustly. (Fixed by
+ Charles-Francois Natali; :issue:`8354`.)
+
* New functions: in the :mod:`site` module, three new functions
return various site- and user-specific paths.
:func:`~site.getsitepackages` returns a list containing all
- global site-packages directories, and
+ global site-packages directories,
:func:`~site.getusersitepackages` returns the path of the user's
- site-packages directory.
+ site-packages directory, and
:func:`~site.getuserbase` returns the value of the :envvar:`USER_BASE`
environment variable, giving the path to a directory that can be used
to store data.
catch and swallow the :exc:`KeyboardInterrupt` exception. (Fixed by
Victor Stinner; :issue:`3137`.)
-* The :mod:`socket` module's :class:`~ssl.SSL` objects now support the
- buffer API, which fixed a test suite failure (fix by Antoine Pitrou;
- :issue:`7133`). :class:`SSL` objects also now automatically set
- OpenSSL's :cmacro:`SSL_MODE_AUTO_RETRY`, which will prevent an error
- code being returned from :meth:`recv` operations that trigger an SSL
- renegotiation (fix by Antoine Pitrou; :issue:`8222`).
-
- The version of OpenSSL being used is now available as the module
- attributes :attr:`OPENSSL_VERSION` (a string),
- :attr:`OPENSSL_VERSION_INFO` (a 5-tuple), and
- :attr:`OPENSSL_VERSION_NUMBER` (an integer). (Added by Antoine
- Pitrou; :issue:`8321`.)
-
- The :func:`~socket.create_connection` function
+* The :func:`~socket.create_connection` function
gained a *source_address* parameter, a ``(host, port)`` 2-tuple
giving the source address that will be used for the connection.
(Contributed by Eldon Ziegler; :issue:`3972`.)
Antoine Pitrou; :issue:`8104`.)
* The :mod:`SocketServer` module's :class:`~SocketServer.TCPServer` class now
- has a :attr:`~SocketServer.TCPServer.disable_nagle_algorithm` class attribute.
- The default value is False; if overridden to be True,
+ supports socket timeouts and disabling the Nagle algorithm.
+ The :attr:`~SocketServer.TCPServer.disable_nagle_algorithm` class attribute
+ defaults to False; if overridden to be True,
new request connections will have the TCP_NODELAY option set to
prevent buffering many small sends into a single TCP packet.
- (Contributed by Kristjan Valur Jonsson; :issue:`6192`.)
+ The :attr:`~SocketServer.TCPServer.timeout` class attribute can hold
+ a timeout in seconds that will be applied to the request socket; if
+ no request is received within that time, :meth:`handle_timeout`
+ will be called and :meth:`handle_request` will return.
+ (Contributed by Kristján Valur Jónsson; :issue:`6192` and :issue:`6267`.)
* Updated module: the :mod:`sqlite3` module has been updated to
version 2.6.0 of the `pysqlite package <http://code.google.com/p/pysqlite/>`__. Version 2.6.0 includes a number of bugfixes, and adds
and then call :meth:`~sqlite3.Connection.load_extension` to load a particular shared library.
(Updated by Gerhard Häring.)
+* The :mod:`ssl` module's :class:`ssl.SSLSocket` objects now support the
+ buffer API, which fixed a test suite failure (fix by Antoine Pitrou;
+ :issue:`7133`) and automatically set
+ OpenSSL's :cmacro:`SSL_MODE_AUTO_RETRY`, which will prevent an error
+ code being returned from :meth:`recv` operations that trigger an SSL
+ renegotiation (fix by Antoine Pitrou; :issue:`8222`).
+
+ The :func:`ssl.wrap_socket` constructor function now takes a
+ *ciphers* argument that's a string listing the encryption algorithms
+ to be allowed; the format of the string is described
+ `in the OpenSSL documentation
+ <http://www.openssl.org/docs/apps/ciphers.html#CIPHER_LIST_FORMAT>`__.
+ (Added by Antoine Pitrou; :issue:`8322`.)
+
+ Another change makes the extension load all of OpenSSL's ciphers and
+ digest algorithms so that they're all available. Some SSL
+ certificates couldn't be verified, reporting an "unknown algorithm"
+ error. (Reported by Beda Kosata, and fixed by Antoine Pitrou;
+ :issue:`8484`.)
+
+ The version of OpenSSL being used is now available as the module
+ attributes :data:`ssl.OPENSSL_VERSION` (a string),
+ :data:`ssl.OPENSSL_VERSION_INFO` (a 5-tuple), and
+ :data:`ssl.OPENSSL_VERSION_NUMBER` (an integer). (Added by Antoine
+ Pitrou; :issue:`8321`.)
+
* The :mod:`struct` module will no longer silently ignore overflow
errors when a value is too large for a particular integer format
code (one of ``bBhHiIlLqQ``); it now always raises a
false for ones that are implicitly global.
(Contributed by Jeremy Hylton.)
+* The :mod:`syslog` module will now use the value of ``sys.argv[0]`` as the
+ identifier instead of the previous default value of ``'python'``.
+ (Changed by Sean Reifschneider; :issue:`8451`.)
+
* The ``sys.version_info`` value is now a named tuple, with attributes
named :attr:`major`, :attr:`minor`, :attr:`micro`,
:attr:`releaselevel`, and :attr:`serial`. (Contributed by Ross
:mod:`tarfile` now supports filtering the :class:`~tarfile.TarInfo`
objects being added to a tar file. When you call :meth:`~tarfile.TarFile.add`,
- instance, you may supply an optional *filter* argument
+ you may supply an optional *filter* argument
that's a callable. The *filter* callable will be passed the
:class:`~tarfile.TarInfo` for every file being added, and can modify and return it.
If the callable returns ``None``, the file will be excluded from the
and has been updated to version 5.2.0 (updated by
Florent Xicluna; :issue:`8024`).
-* The :class:`~UserDict.UserDict` class is now a new-style class. (Changed by
- Benjamin Peterson.)
+* The :mod:`urlparse` module's :func:`~urlparse.urlsplit` now handles
+ unknown URL schemes in a fashion compliant with :rfc:`3986`: if the
+ URL is of the form ``"<something>://..."``, the text before the
+ ``://`` is treated as the scheme, even if it's a made-up scheme that
+ the module doesn't know about. This change may break code that
+ worked around the old behaviour. For example, Python 2.6.4 or 2.5
+ will return the following:
+
+ >>> import urlparse
+ >>> urlparse.urlsplit('invented://host/filename?query')
+ ('invented', '', '//host/filename?query', '', '')
+
+ Python 2.7 (and Python 2.6.5) will return:
+
+ >>> import urlparse
+ >>> urlparse.urlsplit('invented://host/filename?query')
+ ('invented', 'host', '/filename?query', '', '')
+
+ (Python 2.7 actually produces slightly different output, since it
+ returns a named tuple instead of a standard tuple.)
+
+ The :mod:`urlparse` module also supports IPv6 literal addresses as defined by
+ :rfc:`2732` (contributed by Senthil Kumaran; :issue:`2987`). ::
+
+ >>> urlparse.urlparse('http://[1080::8:800:200C:417A]/foo')
+ ParseResult(scheme='http', netloc='[1080::8:800:200C:417A]',
+ path='/foo', params='', query='', fragment='')
+
+* New class: the :class:`~weakref.WeakSet` class in the :mod:`weakref`
+ module is a set that only holds weak references to its elements; elements
+ will be removed once there are no references pointing to them.
+ (Originally implemented in Python 3.x by Raymond Hettinger, and backported
+ to 2.7 by Michael Foord.)
* The ElementTree library, :mod:`xml.etree`, no longer escapes
ampersands and angle brackets when outputting an XML processing
or comment (which looks like ``<!-- comment -->``).
(Patch by Neil Muller; :issue:`2746`.)
+* The XML-RPC client and server, provided by the :mod:`xmlrpclib` and
+ :mod:`SimpleXMLRPCServer` modules, have improved performance by
+ supporting HTTP/1.1 keep-alive and by optionally using gzip encoding
+ to compress the XML being exchanged. The gzip compression is
+ controlled by the :attr:`encode_threshold` attribute of
+ :class:`SimpleXMLRPCRequestHandler`, which contains a size in bytes;
+ responses larger than this will be compressed.
+ (Contributed by Kristján Valur Jónsson; :issue:`6267`.)
+
* The :mod:`zipfile` module's :class:`~zipfile.ZipFile` now supports the context
- management protocol, so you can write ``with zipfile.ZipFile(...) as f: ...``.
+ management protocol, so you can write ``with zipfile.ZipFile(...) as f:``.
(Contributed by Brian Curtin; :issue:`5511`.)
- :mod:`zipfile` now supports archiving empty directories and
+ :mod:`zipfile` now also supports archiving empty directories and
extracts them correctly. (Fixed by Kuba Wieczorek; :issue:`4710`.)
- Reading files out of an archive is now faster, and interleaving
+ Reading files out of an archive is faster, and interleaving
:meth:`~zipfile.ZipFile.read` and :meth:`~zipfile.ZipFile.readline` now works correctly.
(Contributed by Nir Aides; :issue:`7610`.)
:issue:`6003`.)
+.. ======================================================================
+.. whole new modules get described in subsections here
+
+
+.. _importlib-section:
+
+New module: importlib
+------------------------------
+
+Python 3.1 includes the :mod:`importlib` package, a re-implementation
+of the logic underlying Python's :keyword:`import` statement.
+:mod:`importlib` is useful for implementors of Python interpreters and
+to users who wish to write new importers that can participate in the
+import process. Python 2.7 doesn't contain the complete
+:mod:`importlib` package, but instead has a tiny subset that contains
+a single function, :func:`~importlib.import_module`.
+
+``import_module(name, package=None)`` imports a module. *name* is
+a string containing the module or package's name. It's possible to do
+relative imports by providing a string that begins with a ``.``
+character, such as ``..utils.errors``. For relative imports, the
+*package* argument must be provided and is the name of the package that
+will be used as the anchor for
+the relative import. :func:`~importlib.import_module` both inserts the imported
+module into ``sys.modules`` and returns the module object.
+
+Here are some examples::
+
+ >>> from importlib import import_module
+ >>> anydbm = import_module('anydbm') # Standard absolute import
+ >>> anydbm
+ <module 'anydbm' from '/p/python/Lib/anydbm.py'>
+ >>> # Relative import
+ >>> file_util = import_module('..file_util', 'distutils.command')
+ >>> file_util
+ <module 'distutils.file_util' from '/python/Lib/distutils/file_util.pyc'>
+
+:mod:`importlib` was implemented by Brett Cannon and introduced in
+Python 3.1.
+
+
New module: sysconfig
---------------------------------
-XXX A new :mod:`sysconfig` module has been extracted from
-:mod:`distutils` and put in the standard library.
+The :mod:`sysconfig` module has been pulled out of the Distutils
+package, becoming a new top-level module in its own right.
+:mod:`sysconfig` provides functions for getting information about
+Python's build process: compiler switches, installation paths, the
+platform name, and whether Python is running from its source
+directory.
-The :mod:`sysconfig` module provides access to Python's configuration
-information like the list of installation paths and the configuration
-variables relevant for the current platform. (contributed by Tarek)
+Some of the functions in the module are:
-Updated module: ElementTree 1.3
----------------------------------
+* :func:`~sysconfig.get_config_var` returns variables from Python's
+ Makefile and the :file:`pyconfig.h` file.
+* :func:`~sysconfig.get_config_vars` returns a dictionary containing
+ all of the configuration variables.
+* :func:`~sysconfig.getpath` returns the configured path for
+ a particular type of module: the standard library,
+ site-specific modules, platform-specific modules, etc.
+* :func:`~sysconfig.is_python_build` returns true if you're running a
+ binary from a Python source tree, and false otherwise.
-XXX write this.
+Consult the :mod:`sysconfig` documentation for more details and for
+a complete list of functions.
-.. ======================================================================
-.. whole new modules get described in subsections here
+The Distutils package and :mod:`sysconfig` are now maintained by Tarek
+Ziadé, who has also started a Distutils2 package (source repository at
+http://hg.python.org/distutils2/) for developing a next-generation
+version of Distutils.
+
+
+ttk: Themed Widgets for Tk
+--------------------------
+
+Tcl/Tk 8.5 includes a set of themed widgets that re-implement basic Tk
+widgets but have a more customizable appearance and can therefore more
+closely resemble the native platform's widgets. This widget
+set was originally called Tile, but was renamed to Ttk (for "themed Tk")
+on being added to Tcl/Tck release 8.5.
+To learn more, read the :mod:`ttk` module documentation. You may also
+wish to read the Tcl/Tk manual page describing the
+Ttk theme engine, available at
+http://www.tcl.tk/man/tcl8.5/TkCmd/ttk_intro.htm. Some
+screenshots of the Python/Ttk code in use are at
+http://code.google.com/p/python-ttk/wiki/Screenshots.
-Unit Testing Enhancements
+The :mod:`ttk` module was written by Guilherme Polo and added in
+:issue:`2983`. An alternate version called ``Tile.py``, written by
+Martin Franklin and maintained by Kevin Walzer, was proposed for
+inclusion in :issue:`2618`, but the authors argued that Guilherme
+Polo's work was more comprehensive.
+
+
+.. _unittest-section:
+
+Updated module: unittest
---------------------------------
-The :mod:`unittest` module was enhanced in several ways.
-The progress messages now shows 'x' for expected failures
+The :mod:`unittest` module was greatly enhanced; many
+new features were added. Most of these features were implemented
+by Michael Foord, unless otherwise noted. The enhanced version of
+the module is downloadable separately for use with Python versions 2.4 to 2.6,
+packaged as the :mod:`unittest2` package, from
+http://pypi.python.org/pypi/unittest2.
+
+When used from the command line, the module can automatically discover
+tests. It's not as fancy as `py.test <http://pytest.org>`__ or
+`nose <http://code.google.com/p/python-nose/>`__, but provides a simple way
+to run tests kept within a set of package directories. For example,
+the following command will search the :file:`test/` subdirectory for
+any importable test files named ``test*.py``::
+
+ python -m unittest discover -s test
+
+Consult the :mod:`unittest` module documentation for more details.
+(Developed in :issue:`6001`.)
+
+The :func:`main` function supports some other new options:
+
+* :option:`-b` or :option:`--buffer` will buffer the standard output
+ and standard error streams during each test. If the test passes,
+ any resulting output will be discarded; on failure, the buffered
+ output will be displayed.
+
+* :option:`-c` or :option:`--catch` will cause the control-C interrupt
+ to be handled more gracefully. Instead of interrupting the test
+ process immediately, the currently running test will be completed
+ and then the partial results up to the interruption will be reported.
+ If you're impatient, a second press of control-C will cause an immediate
+ interruption.
+
+ This control-C handler tries to avoid causing problems when the code
+ being tested or the tests being run have defined a signal handler of
+ their own, by noticing that a signal handler was already set and
+ calling it. If this doesn't work for you, there's a
+ :func:`removeHandler` decorator that can be used to mark tests that
+ should have the control-C handling disabled.
+
+* :option:`-f` or :option:`--failfast` makes
+ test execution stop immediately when a test fails instead of
+ continuing to execute further tests. (Suggested by Cliff Dyer and
+ implemented by Michael Foord; :issue:`8074`.)
+
+The progress messages now show 'x' for expected failures
and 'u' for unexpected successes when run in verbose mode.
(Contributed by Benjamin Peterson.)
-Test cases can raise the :exc:`~unittest.SkipTest` exception to skip a test.
-(:issue:`1034053`.)
-.. XXX describe test discovery (Contributed by Michael Foord; :issue:`6001`.)
+Test cases can raise the :exc:`~unittest.SkipTest` exception to skip a
+test (:issue:`1034053`).
The error messages for :meth:`~unittest.TestCase.assertEqual`,
:meth:`~unittest.TestCase.assertTrue`, and :meth:`~unittest.TestCase.assertFalse`
provide will be printed for failures. (Added by Michael Foord; :issue:`5663`.)
The :meth:`~unittest.TestCase.assertRaises` method now
-return a context handler when called without providing a callable
+returns a context handler when called without providing a callable
object to run. For example, you can write this::
with self.assertRaises(KeyError):
The methods :meth:`~unittest.TestCase.addCleanup` and
:meth:`~unittest.TestCase.doCleanups` were added.
-:meth:`~unittest.TestCase.addCleanup` allows you to add cleanup functions that
+:meth:`~unittest.TestCase.addCleanup` lets you add cleanup functions that
will be called unconditionally (after :meth:`~unittest.TestCase.setUp` if
:meth:`~unittest.TestCase.setUp` fails, otherwise after :meth:`~unittest.TestCase.tearDown`). This allows
for much simpler resource allocation and deallocation during tests
differences in the two strings. This comparison is now used by
default when Unicode strings are compared with :meth:`~unittest.TestCase.assertEqual`.
-* :meth:`~unittest.TestCase.assertRegexpMatches` checks whether its first argument is a
- string matching a regular expression provided as its second argument.
-
- .. XXX add assertNotRegexpMatches see issue 8038
+* :meth:`~unittest.TestCase.assertRegexpMatches` and
+ :meth:`~unittest.TestCase.assertNotRegexpMatches` checks whether the
+ first argument is a string matching or not matching the regular
+ expression provided as the second argument (:issue:`8038`).
* :meth:`~unittest.TestCase.assertRaisesRegexp` checks whether a particular exception
is raised, and then also checks that the string representation of
all of the key/value pairs in *first* are found in *second*.
* :meth:`~unittest.TestCase.assertAlmostEqual` and :meth:`~unittest.TestCase.assertNotAlmostEqual` test
- whether *first* and *second* are approximately equal by computing
- their difference, rounding the result to an optionally-specified number
- of *places* (the default is 7), and comparing to zero.
+ whether *first* and *second* are approximately equal. This method
+ can either round their difference to an optionally-specified number
+ of *places* (the default is 7) and compare it to zero, or require
+ the difference to be smaller than a supplied *delta* value.
* :meth:`~unittest.TestLoader.loadTestsFromName` properly honors the
:attr:`~unittest.TestLoader.suiteClass` attribute of
objects being compared are of the specified type. This function
should compare the two objects and raise an exception if they don't
match; it's a good idea for the function to provide additional
- information about why the two objects are matching, much as the new
+ information about why the two objects aren't matching, much as the new
sequence comparison methods do.
:func:`unittest.main` now takes an optional ``exit`` argument. If
-False, :func:`~unittest.main` doesn't call :func:`sys.exit`, allowing it to be
-used from the interactive interpreter. (Contributed by J. Pablo
-Fernández; :issue:`3379`.)
-
-A new command-line switch, :option:`-f` or :option:`--failfast`, makes
-test execution stop immediately when a test fails instead of
-continuing to execute further tests. (Suggested by Cliff Dyer and
-implemented by Michael Foord; :issue:`8074`.)
-
-.. XXX document the other new switches
+False, :func:`~unittest.main` doesn't call :func:`sys.exit`, allowing
+:func:`main` to be used from the interactive interpreter.
+(Contributed by J. Pablo Fernández; :issue:`3379`.)
:class:`~unittest.TestResult` has new :meth:`~unittest.TestResult.startTestRun` and
:meth:`~unittest.TestResult.stopTestRun` methods that are called immediately before
With all these changes, the :file:`unittest.py` was becoming awkwardly
large, so the module was turned into a package and the code split into
several files (by Benjamin Peterson). This doesn't affect how the
-module is imported.
-
-
-.. _importlib-section:
-
-importlib: Importing Modules
-------------------------------
-
-Python 3.1 includes the :mod:`importlib` package, a re-implementation
-of the logic underlying Python's :keyword:`import` statement.
-:mod:`importlib` is useful for implementors of Python interpreters and
-to users who wish to write new importers that can participate in the
-import process. Python 2.7 doesn't contain the complete
-:mod:`importlib` package, but instead has a tiny subset that contains
-a single function, :func:`~importlib.import_module`.
-
-``import_module(name, package=None)`` imports a module. *name* is
-a string containing the module or package's name. It's possible to do
-relative imports by providing a string that begins with a ``.``
-character, such as ``..utils.errors``. For relative imports, the
-*package* argument must be provided and is the name of the package that
-will be used as the anchor for
-the relative import. :func:`~importlib.import_module` both inserts the imported
-module into ``sys.modules`` and returns the module object.
-
-Here are some examples::
-
- >>> from importlib import import_module
- >>> anydbm = import_module('anydbm') # Standard absolute import
- >>> anydbm
- <module 'anydbm' from '/p/python/Lib/anydbm.py'>
- >>> # Relative import
- >>> sysconfig = import_module('..sysconfig', 'distutils.command')
- >>> sysconfig
- <module 'distutils.sysconfig' from '/p/python/Lib/distutils/sysconfig.pyc'>
-
-:mod:`importlib` was implemented by Brett Cannon and introduced in
-Python 3.1.
-
-
-ttk: Themed Widgets for Tk
---------------------------
-
-Tcl/Tk 8.5 includes a set of themed widgets that re-implement basic Tk
-widgets but have a more customizable appearance and can therefore more
-closely resemble the native platform's widgets. This widget
-set was originally called Tile, but was renamed to Ttk (for "themed Tk")
-on being added to Tcl/Tck release 8.5.
+module is imported or used.
-XXX write a brief discussion and an example here.
+.. seealso::
-The :mod:`ttk` module was written by Guilherme Polo and added in
-:issue:`2983`. An alternate version called ``Tile.py``, written by
-Martin Franklin and maintained by Kevin Walzer, was proposed for
-inclusion in :issue:`2618`, but the authors argued that Guilherme
-Polo's work was more comprehensive.
+ http://www.voidspace.org.uk/python/articles/unittest2.shtml
+ Describes the new features, how to use them, and the
+ rationale for various design decisions. (By Michael Foord.)
+.. _elementtree-section:
-Deprecations and Removals
-=========================
+Updated module: ElementTree 1.3
+---------------------------------
-* :func:`contextlib.nested`, which allows handling more than one context manager
- with one :keyword:`with` statement, has been deprecated; :keyword:`with`
- supports multiple context managers syntactically now.
+The version of the ElementTree library included with Python was updated to
+version 1.3. Some of the new features are:
+
+* The various parsing functions now take a *parser* keyword argument
+ giving an :class:`XMLParser` instance that will
+ be used. This makes it possible to override the file's internal encoding::
+
+ p = ET.XMLParser(encoding='utf-8')
+ t = ET.XML("""<root/>""", parser=p)
+
+ Errors in parsing XML now raise a :exc:`ParseError` exception, whose
+ instances have a :attr:`position` attribute
+ containing a (*line*, *column*) tuple giving the location of the problem.
+
+* ElementTree's code for converting trees to a string has been
+ significantly reworked, making it roughly twice as fast in many
+ cases. The :class:`ElementTree` :meth:`write` and :class:`Element`
+ :meth:`write` methods now have a *method* parameter that can be
+ "xml" (the default), "html", or "text". HTML mode will output empty
+ elements as ``<empty></empty>`` instead of ``<empty/>``, and text
+ mode will skip over elements and only output the text chunks. If
+ you set the :attr:`tag` attribute of an element to ``None`` but
+ leave its children in place, the element will be omitted when the
+ tree is written out, so you don't need to do more extensive rearrangement
+ to remove a single element.
+
+ Namespace handling has also been improved. All ``xmlns:<whatever>``
+ declarations are now output on the root element, not scattered throughout
+ the resulting XML. You can set the default namespace for a tree
+ by setting the :attr:`default_namespace` attribute and can
+ register new prefixes with :meth:`register_namespace`. In XML mode,
+ you can use the true/false *xml_declaration* parameter to suppress the
+ XML declaration.
+
+* New :class:`Element` method: :meth:`extend` appends the items from a
+ sequence to the element's children. Elements themselves behave like
+ sequences, so it's easy to move children from one element to
+ another::
+
+ from xml.etree import ElementTree as ET
+
+ t = ET.XML("""<list>
+ <item>1</item> <item>2</item> <item>3</item>
+ </list>""")
+ new = ET.XML('<root/>')
+ new.extend(t)
+
+ # Outputs <root><item>1</item>...</root>
+ print ET.tostring(new)
+
+* New :class:`Element` method: :meth:`iter` yields the children of the
+ element as a generator. It's also possible to write ``for child in
+ elem:`` to loop over an element's children. The existing method
+ :meth:`getiterator` is now deprecated, as is :meth:`getchildren`
+ which constructs and returns a list of children.
+
+* New :class:`Element` method: :meth:`itertext` yields all chunks of
+ text that are descendants of the element. For example::
+
+ t = ET.XML("""<list>
+ <item>1</item> <item>2</item> <item>3</item>
+ </list>""")
+
+ # Outputs ['\n ', '1', ' ', '2', ' ', '3', '\n']
+ print list(t.itertext())
+
+* Deprecated: using an element as a Boolean (i.e., ``if elem:``) would
+ return true if the element had any children, or false if there were
+ no children. This behaviour is confusing -- ``None`` is false, but
+ so is a childless element? -- so it will now trigger a
+ :exc:`FutureWarning`. In your code, you should be explicit: write
+ ``len(elem) != 0`` if you're interested in the number of children,
+ or ``elem is not None``.
+
+Fredrik Lundh develops ElementTree and produced the 1.3 version;
+you can read his article describing 1.3 at
+http://effbot.org/zone/elementtree-13-intro.htm.
+Florent Xicluna updated the version included with
+Python, after discussions on python-dev and in :issue:`6472`.)
.. ======================================================================
<http://sourceware.org/gdb/current/onlinedocs/gdb/Python.html>`__.
When you begin debugging an executable program P, GDB will look for
a file named ``P-gdb.py`` and automatically read it. Dave Malcolm
- contributed a :file:`python-gdb.py` that adds a number of useful
- commands when debugging Python itself. For example, there are
- ``py-up`` and ``py-down`` that go up or down one Python stack frame,
+ contributed a :file:`python-gdb.py` that adds a number of
+ commands useful when debugging Python itself. For example,
+ ``py-up`` and ``py-down`` go up or down one Python stack frame,
which usually corresponds to several C stack frames. ``py-print``
prints the value of a Python variable, and ``py-bt`` prints the
Python stack trace. (Added as a result of :issue:`8032`.)
* :cfunc:`Py_AddPendingCall` is now thread-safe, letting any
worker thread submit notifications to the main Python thread. This
is particularly useful for asynchronous IO operations.
- (Contributed by Kristjan Valur Jonsson; :issue:`4293`.)
+ (Contributed by Kristján Valur Jónsson; :issue:`4293`.)
* New function: :cfunc:`PyCode_NewEmpty` creates an empty code object;
only the filename, function name, and first line number are required.
- This is useful to extension modules that are attempting to
+ This is useful for extension modules that are attempting to
construct a more useful traceback stack. Previously such
extensions needed to call :cfunc:`PyCode_New`, which had many
more arguments. (Added by Jeffrey Yasskin.)
* New function: :cfunc:`PyErr_NewExceptionWithDoc` creates a new
exception class, just as the existing :cfunc:`PyErr_NewException` does,
but takes an extra ``char *`` argument containing the docstring for the
- new exception class. (Added by the 'lekma' user on the Python bug tracker;
+ new exception class. (Added by 'lekma' on the Python bug tracker;
:issue:`7033`.)
* New function: :cfunc:`PyFrame_GetLineNumber` takes a frame object
:cfunc:`PyOS_ascii_strtod` and :cfunc:`PyOS_ascii_atof` functions
are now deprecated.
+* New function: :cfunc:`PySys_SetArgvEx` sets the value of
+ ``sys.argv`` and can optionally update ``sys.path`` to include the
+ directory containing the script named by ``sys.argv[0]`` depending
+ on the value of an *updatepath* parameter.
+
+ This function was added to close a security hole for applications
+ that embed Python. The old function, :cfunc:`PySys_SetArgv`, would
+ always update ``sys.path``, and sometimes it would add the current
+ directory. This meant that, if you ran an application embedding
+ Python in a directory controlled by someone else, attackers could
+ put a Trojan-horse module in the directory (say, a file named
+ :file:`os.py`) that your application would then import and run.
+
+ If you maintain a C/C++ application that embeds Python, check
+ whether you're calling :cfunc:`PySys_SetArgv` and carefully consider
+ whether the application should be using :cfunc:`PySys_SetArgvEx`
+ with *updatepath* set to false.
+
+ Security issue reported as `CVE-2008-5983
+ <http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-5983>`_;
+ discussed in :issue:`5753`, and fixed by Antoine Pitrou.
+
* New macros: the Python header files now define the following macros:
:cmacro:`Py_ISALNUM`,
:cmacro:`Py_ISALPHA`,
.. XXX these macros don't seem to be described in the c-api docs.
+* Removed function: :cmacro:`PyEval_CallObject` is now only available
+ as a macro. A function version was being kept around to preserve
+ ABI linking compatibility, but that was in 1997; it can certainly be
+ deleted by now. (Removed by Antoine Pitrou; :issue:`8276`.)
+
* New format codes: the :cfunc:`PyFormat_FromString`,
- :cfunc:`PyFormat_FromStringV`, and :cfunc:`PyErr_Format` now
- accepts ``%lld`` and ``%llu`` format codes for displaying values of
+ :cfunc:`PyFormat_FromStringV`, and :cfunc:`PyErr_Format` functions now
+ accept ``%lld`` and ``%llu`` format codes for displaying
C's :ctype:`long long` types.
(Contributed by Mark Dickinson; :issue:`7228`.)
ever release the lock, since the other threads weren't replicated,
and the child process would no longer be able to perform imports.
- Python 2.7 now acquires the import lock before performing an
+ Python 2.7 acquires the import lock before performing an
:func:`os.fork`, and will also clean up any locks created using the
:mod:`threading` module. C extension modules that have internal
locks, or that call :cfunc:`fork()` themselves, will not benefit
being raised when an interpreter shuts down.
(Patch by Adam Olsen; :issue:`1722344`.)
+* When using the :ctype:`PyMemberDef` structure to define attributes
+ of a type, Python will no longer let you try to delete or set a
+ :const:`T_STRING_INPLACE` attribute.
+
+ .. rev 79644
+
* Global symbols defined by the :mod:`ctypes` module are now prefixed
with ``Py``, or with ``_ctypes``. (Implemented by Thomas
Heller; :issue:`3102`.)
building the :mod:`pyexpat` module to use the system Expat library.
(Contributed by Arfrever Frehtes Taifersar Arahesis; :issue:`7609`.)
-* New configure option: compiling Python with the
+* New configure option: the
:option:`--with-valgrind` option will now disable the pymalloc
allocator, which is difficult for the Valgrind memory-error detector
to analyze correctly.
Valgrind will therefore be better at detecting memory leaks and
overruns. (Contributed by James Henstridge; :issue:`2422`.)
-* New configure option: you can now supply no arguments to
- :option:`--with-dbmliborder=` in order to build none of the various
+* New configure option: you can now supply an empty string to
+ :option:`--with-dbmliborder=` in order to disable all of the various
DBM modules. (Added by Arfrever Frehtes Taifersar Arahesis;
:issue:`6491`.)
Arfrever Frehtes Taifersar Arahesis; :issue:`6094`.)
+.. _whatsnew27-capsules:
+
+Capsules
+-------------------
+
+Python 3.1 adds a new C datatype, :ctype:`PyCapsule`, for providing a
+C API to an extension module. A capsule is essentially the holder of
+a C ``void *`` pointer, and is made available as a module attribute; for
+example, the :mod:`socket` module's API is exposed as ``socket.CAPI``,
+and :mod:`unicodedata` exposes ``ucnhash_CAPI``. Other extensions
+can import the module, access its dictionary to get the capsule
+object, and then get the ``void *`` pointer, which will usually point
+to an array of pointers to the module's various API functions.
+
+There is an existing data type already used for this,
+:ctype:`PyCObject`, but it doesn't provide type safety. Evil code
+written in pure Python could cause a segmentation fault by taking a
+:ctype:`PyCObject` from module A and somehow substituting it for the
+:ctype:`PyCObject` in module B. Capsules know their own name,
+and getting the pointer requires providing the name::
+
+ void *vtable;
+
+ if (!PyCapsule_IsValid(capsule, "mymodule.CAPI") {
+ PyErr_SetString(PyExc_ValueError, "argument type invalid");
+ return NULL;
+ }
+
+ vtable = PyCapsule_GetPointer(capsule, "mymodule.CAPI");
+
+You are assured that ``vtable`` points to whatever you're expecting.
+If a different capsule was passed in, :cfunc:`PyCapsule_IsValid` would
+detect the mismatched name and return false. Refer to
+:ref:`using-capsules` for more information on using these objects.
+
+Python 2.7 now uses capsules internally to provide various
+extension-module APIs, but the :cfunc:`PyCObject_AsVoidPtr` was
+modified to handle capsules, preserving compile-time compatibility
+with the :ctype:`CObject` interface. Use of
+:cfunc:`PyCObject_AsVoidPtr` will signal a
+:exc:`PendingDeprecationWarning`, which is silent by default.
+
+Implemented in Python 3.1 and backported to 2.7 by Larry Hastings;
+discussed in :issue:`5630`.
+
+
.. ======================================================================
Port-Specific Changes: Windows
and :data:`LIBRARIES_ASSEMBLY_NAME_PREFIX`.
(Contributed by David Cournapeau; :issue:`4365`.)
+* The :mod:`_winreg` module for accessing the registry now implements
+ the :func:`CreateKeyEx` and :func:`DeleteKeyEx` functions, extended
+ versions of previously-supported functions that take several extra
+ arguments. The :func:`DisableReflectionKey`,
+ :func:`EnableReflectionKey`, and :func:`QueryReflectionKey` were also
+ tested and documented.
+ (Implemented by Brian Curtin: :issue:`7347`.)
+
* The new :cfunc:`_beginthreadex` API is used to start threads, and
the native thread-local storage functions are now used.
- (Contributed by Kristjan Valur Jonsson; :issue:`3582`.)
+ (Contributed by Kristján Valur Jónsson; :issue:`3582`.)
* The :func:`os.kill` function now works on Windows. The signal value
can be the constants :const:`CTRL_C_EVENT`,
- :const:`CTRL_BREAK_EVENT`, or any integer. The Control-C and
- Control-Break keystroke events can be sent to subprocesses; any
- other value will use the :cfunc:`TerminateProcess` API.
- (Contributed by Miki Tebeka; :issue:`1220212`.)
+ :const:`CTRL_BREAK_EVENT`, or any integer. The first two constants
+ will send Control-C and Control-Break keystroke events to
+ subprocesses; any other value will use the :cfunc:`TerminateProcess`
+ API. (Contributed by Miki Tebeka; :issue:`1220212`.)
* The :func:`os.listdir` function now correctly fails
for an empty path. (Fixed by Hirokazu Yamamoto; :issue:`5913`.)
installation and a user-installed copy of the same version.
(Changed by Ronald Oussoren; :issue:`4865`.)
+Port-Specific Changes: FreeBSD
+-----------------------------------
+
+* FreeBSD 7.1's :const:`SO_SETFIB` constant, used with
+ :func:`~socket.getsockopt`/:func:`~socket.setsockopt` to select an
+ alternate routing table, is now available in the :mod:`socket`
+ module. (Added by Kyle VanderBeek; :issue:`8235`.)
Other Changes and Fixes
=======================
* Two benchmark scripts, :file:`iobench` and :file:`ccbench`, were
added to the :file:`Tools` directory. :file:`iobench` measures the
- speed of built-in file I/O objects (as returned by :func:`open`)
+ speed of the built-in file I/O objects returned by :func:`open`
while performing various operations, and :file:`ccbench` is a
concurrency benchmark that tries to measure computing throughput,
thread switching latency, and IO processing bandwidth when
performing several tasks using a varying number of threads.
+* The :file:`Tools/i18n/msgfmt.py` script now understands plural
+ forms in :file:`.po` files. (Fixed by Martin von Löwis;
+ :issue:`5464`.)
+
* When importing a module from a :file:`.pyc` or :file:`.pyo` file
with an existing :file:`.py` counterpart, the :attr:`co_filename`
attributes of the resulting code objects are overwritten when the
This section lists previously described changes and other bugfixes
that may require changes to your code:
-* When using :class:`Decimal` instances with a string's
- :meth:`format` method, the default alignment was previously
- left-alignment. This has been changed to right-alignment, which might
- change the output of your programs.
- (Changed by Mark Dickinson; :issue:`6857`.)
+* The :func:`range` function processes its arguments more
+ consistently; it will now call :meth:`__int__` on non-float,
+ non-integer arguments that are supplied to it. (Fixed by Alexander
+ Belopolsky; :issue:`1533`.)
- Another :meth:`format`-related change: the default precision used
- for floating-point and complex numbers was changed from 6 decimal
+* The string :meth:`format` method changed the default precision used
+ for floating-point and complex numbers from 6 decimal
places to 12, which matches the precision used by :func:`str`.
(Changed by Eric Smith; :issue:`5920`.)
affects new-style classes (derived from :class:`object`) and C extension
types. (:issue:`6101`.)
-* The :meth:`readline` method of :class:`StringIO` objects now does
- nothing when a negative length is requested, as other file-like
- objects do. (:issue:`7348`).
+* Due to a bug in Python 2.6, the *exc_value* parameter to
+ :meth:`__exit__` methods was often the string representation of the
+ exception, not an instance. This was fixed in 2.7, so *exc_value*
+ will be an instance as expected. (Fixed by Florent Xicluna;
+ :issue:`7853`.)
+
+* When a restricted set of attributes were set using ``__slots__``,
+ deleting an unset attribute would not raise :exc:`AttributeError`
+ as you would expect. Fixed by Benjamin Peterson; :issue:`7604`.)
In the standard library:
+* Operations with :class:`datetime` instances that resulted in a year
+ falling outside the supported range didn't always raise
+ :exc:`OverflowError`. Such errors are now checked more carefully
+ and will now raise the exception. (Reported by Mark Leander, patch
+ by Anand B. Pillai and Alexander Belopolsky; :issue:`7150`.)
+
+* When using :class:`Decimal` instances with a string's
+ :meth:`format` method, the default alignment was previously
+ left-alignment. This has been changed to right-alignment, which might
+ change the output of your programs.
+ (Changed by Mark Dickinson; :issue:`6857`.)
+
+ Comparisons involving a signaling NaN value (or ``sNAN``) now signal
+ :const:`InvalidOperation` instead of silently returning a true or
+ false value depending on the comparison operator. Quiet NaN values
+ (or ``NaN``) are now hashable. (Fixed by Mark Dickinson;
+ :issue:`7279`.)
+
* The ElementTree library, :mod:`xml.etree`, no longer escapes
ampersands and angle brackets when outputting an XML processing
instruction (which looks like `<?xml-stylesheet href="#style1"?>`)
or comment (which looks like `<!-- comment -->`).
(Patch by Neil Muller; :issue:`2746`.)
+* The :meth:`readline` method of :class:`StringIO` objects now does
+ nothing when a negative length is requested, as other file-like
+ objects do. (:issue:`7348`).
+
+* The :mod:`syslog` module will now use the value of ``sys.argv[0]`` as the
+ identifier instead of the previous default value of ``'python'``.
+ (Changed by Sean Reifschneider; :issue:`8451`.)
+
+* The :mod:`tarfile` module's default error handling has changed, to
+ no longer suppress fatal errors. The default error level was previously 0,
+ which meant that errors would only result in a message being written to the
+ debug log, but because the debug log is not activated by default,
+ these errors go unnoticed. The default error level is now 1,
+ which raises an exception if there's an error.
+ (Changed by Lars Gustäbel; :issue:`7357`.)
+
+* The :mod:`urlparse` module's :func:`~urlparse.urlsplit` now handles
+ unknown URL schemes in a fashion compliant with :rfc:`3986`: if the
+ URL is of the form ``"<something>://..."``, the text before the
+ ``://`` is treated as the scheme, even if it's a made-up scheme that
+ the module doesn't know about. This change may break code that
+ worked around the old behaviour. For example, Python 2.6.4 or 2.5
+ will return the following:
+
+ >>> import urlparse
+ >>> urlparse.urlsplit('invented://host/filename?query')
+ ('invented', '', '//host/filename?query', '', '')
+
+ Python 2.7 (and Python 2.6.5) will return:
+
+ >>> import urlparse
+ >>> urlparse.urlsplit('invented://host/filename?query')
+ ('invented', 'host', '/filename?query', '', '')
+
+ (Python 2.7 actually produces slightly different output, since it
+ returns a named tuple instead of a standard tuple.)
+
For C extensions:
* C extensions that use integer format codes with the ``PyArg_Parse*``
:cfunc:`PyOS_ascii_strtod` and :cfunc:`PyOS_ascii_atof` functions,
which are now deprecated.
+For applications that embed Python:
+
+* The :cfunc:`PySys_SetArgvEx` function was added, letting
+ applications close a security hole when the existing
+ :cfunc:`PySys_SetArgv` function was used. Check whether you're
+ calling :cfunc:`PySys_SetArgv` and carefully consider whether the
+ application should be using :cfunc:`PySys_SetArgvEx` with
+ *updatepath* set to false.
.. ======================================================================
The author would like to thank the following people for offering
suggestions, corrections and assistance with various drafts of this
-article: Ryan Lovett, R. David Murray, Hugh Secker-Walker.
+article: Nick Coghlan, Philip Jenvey, Ryan Lovett, R. David Murray,
+Hugh Secker-Walker.
projects / python / commitdiff