Python 3.4.0 正式版发布

Python 3.4.0 发布，此版本包括一系列 3.x 系列的改进，数百个小的改进和 bug 修复。

值得注意的更新内容如下：

新语法特性:

• Python 3.4 并未添加任何新的语法特性

其他新特性:

• pip should always be available (PEP 453).

• Newly created file descriptors are non-inheritable(PEP 446).

• command line option for isolated mode(issue 16499).

• improvements in the handling of codecsthat are not text encodings (multiple issues).

• A ModuleSpec Type for the Import System (PEP 451).  (Affects importer authors.)

• The marshal format has been made more compact and efficient (issue 16475).

新的库模块:

• asyncio: New provisional API for asynchronous IO (PEP 3156).

• ensurepip: Bootstrapping the pip installer(PEP 453).

• enum: Support for enumeration types(PEP 435).

• pathlib: Object-oriented filesystem paths(PEP 428).

• selectors: High-level and efficient I/O multiplexing, built upon the selectmodule primitives (part of PEP 3156).

• statistics: A basic numerically stable statistics library (PEP 450).

• tracemalloc: Trace Python memory allocations (PEP 454).

库模块中重大的改进:

• Single-dispatch generic functions infunctools (PEP 443).

• New pickle protocol 4 (PEP 3154).

• multiprocessing now has an option to avoid using os.fork on Unix (issue 8713).

• email has a new submodule, contentmanager, and a new Message subclass (EmailMessage) that simplify MIME handling (issue 18891).

• The inspect and pydoc modules are now capable of correct introspection of a much wider variety of callable objects, which improves the output of the Python help() system.

• The ipaddress module API has been declared stable

安全改进:

• Secure and interchangeable hash algorithm(PEP 456).

• Make newly created file descriptors non-inheritable(PEP 446) to avoid leaking file descriptors to child processes.

• New command line option for isolated mode, (issue 16499).

• multiprocessing now has an option to avoid using os.fork on Unix.  spawn andforkserver are more secure because they avoid sharing data with child processes.

• multiprocessing child processes on Windows no longer inherit all of the parent’s inheritable handles, only the necessary ones.

• A new hashlib.pbkdf2_hmac() function provides the PKCS#5 password-based key derivation function 2.

• TLSv1.1 and TLSv1.2 support for ssl.

• Retrieving certificates from the Windows system cert store support for ssl.

• Server-side SNI (Server Name Indication) support for ssl.

• The ssl.SSLContext class has a lot of improvements.

• All modules in the standard library that support SSL now support server certificate verification, including hostname matching (ssl.match_hostname()) and CRLs (Certificate Revocation lists, seessl.SSLContext.load_verify_locations()).

CPython 实现改进:

• Safe object finalization ().

• Leveraging PEP 442, in most cases module globals are no longer set to None during finalization (issue 18214).

• Configurable memory allocators (PEP 445).

• Argument Clinic (PEP 436).