Issue #26604:
* Add a new optional source parameter to _warnings.warn() and warnings.warn()
* Modify asyncore, asyncio and _pyio modules to set the source parameter when
logging a ResourceWarning warning
getaddrinfo takes an exclusive lock on some platforms, causing clients to queue
up waiting for the lock if many names are being resolved concurrently. Users
may want to handle name resolution in their own code, for the sake of caching,
using an alternate resolver, or to measure DNS duration separately from
connection duration. Skip getaddrinfo if the "host" passed into
create_connection is already resolved.
See https://github.com/python/asyncio/pull/302 for details.
Patch by A. Jesse Jiryu Davis.
Previous approach of installing coroutine wrapper in loop.set_debug() and
uninstalling it in loop.close() was very fragile. Most of asyncio tests
do not call loop.close() at all. Since coroutine wrapper is a global
setting, we have to make sure that it's only set when the loop is
running, and is automatically unset when it stops running.
Issue #24017.
* _check_resolved_address() is implemented with getaddrinfo() which is slow
* If available, use socket.inet_pton() instead of socket.getaddrinfo(), because
it is much faster
Microbenchmark (timeit) on Fedora 21 (Python 3.4, Linux 3.17, glibc 2.20) to
validate the IPV4 address "127.0.0.1" or the IPv6 address "::1":
* getaddrinfo() 10.4 usec per loop
* inet_pton(): 0.285 usec per loop
On glibc older than 2.14, getaddrinfo() always requests the list of all local
IP addresses to the kernel (using a NETLINK socket). getaddrinfo() has other
known issues, it's better to avoid it when it is possible.
* Remove unused SSLProtocol._closing attribute
* test_sslproto: skip test if ssl module is missing
* Python issue #23208: Don't use the traceback of the current handle if we
already know the traceback of the source. The handle may be more revelant,
but having 3 tracebacks (handle, source, exception) becomes more difficult to
read. The handle may be preferred later but it requires more work to make
this choice.
In debug mode, BaseEventLoop._run_once() now sets the
BaseEventLoop._current_handle attribute to the handle currently executed.
In release mode or when no handle is executed, the attribute is None.
BaseEventLoop.default_exception_handler() displays the traceback of the current
handle if available.