[Libevent-users] ANN: Libevent 2.1.3-alpha is released!

[Nick Mathewson <nickm@xxxxxxxxxxxxx>]

Announcing Libevent 2.1.3-alpha
===============================

Libevent 2.1.3-alpha is released!

This is the third release in the Libevent 2.1 series. As the "alpha"
should tell you, this is not a stable release: you should not run it
unless you're willing to debug together.  If you want a stable version
of Libevent, stick to the 2.0 series for now.

The package is available from the website, at http://libevent.org/

There are GPG signatures there too; you should probably verify them,
to make sure you get the software you think you are getting.

What's new in Libevent 2.1.3-alpha
==================================

This release has a bunch of stuff, including:

   * An experimental "finalization" feature to try to solve the
     deadlock in multithreaded bufferevent use.
   * Numerous bug and portability fixes.

For explanations of what's changed in 2.1 so far, see "What's New In
Libevent 2.1", available as "whatsnew-2.1.txt" in the source distribution,
or online at https://raw.github.com/libevent/libevent/master/whatsnew-2.1.txt

The whole darn ChangeLog
========================

 Libevent 2.1.3-alpha fixes various bugs, adds new unit tests, and cleans
 up the code in a couple of places. It has a new callback in evhttp for
 reporting errors during a request, a new feature for allowing evdns to
 not keep the event_base looping when there are no requests inflight, and
 example code for writing an https client.

 Libevent 2.1.3-alpha also has an important new (experimental) event
 finalization feature to allow safe event teardown in multithreaded
 programs. This ought to fix the longstanding bug with deadlocks in
 multithreaded use of SSL-based bufferevents that some people have been
 experiencing since Libevent 2.0.


 Core (event finalization)
   o Implement event_finalize() and related functions to avoid certain
     deadlocks (8eedeab)
   o Use finalization feature so bufferevents can avoid deadlocks (02fbf68)
   o Always run pending finalizers when event_base_free() is called (e9ebef8)
   o Remove bufferevent_del_generic_timeout_cbs as now unused (4ea4c6a)
   o More documentation for finalization feature (a800b91)
   o Make the event_finalize* functions return an error code (5d11f4f)
   o Mark the finalize stuff as experiemental in case it needs to
     change (23e2e29)

 Evdns
   o evdns: New flag to make evdns not prevent the event loop from
     exiting (6b7fa62 Azat Khuzhin)

 Bugfixes (Core)
   o Make event_remove_timer behave correctly with persistent timers (5623e80)
   o Unit test for event_remove_timer with EV_PERSIST. (96150dd)
   o Double-check next timeout when adding events (9443868 Nate Rosenblum)
   o event_base_update_cache_time should be a no-op if the loop isn't
     running (5e6fa2a)

 Bugfixes (evhttp, crash fix, from 2.0)
   o fix #73 and fix http_connection_fail_test to catch it (b618204 Greg Hazel)

 Bugfixes (compilation and portability, from 2.0)
   o Fix compilation with WIN32_HAVE_CONDITION_VARIABLES enabled (7e45739)
   o Fix missing AC_PROG_SED on older Autoconfs (9ab2b3f Tay Ray Chuan)
   o Backport libevent to vanilla Autoconf 2.59 (as used in RHEL5)
     (74d4c44 Kevin Bowling)
   o Use AC_CONFIG_HEADERS in place of AM_CONFIG_HEADERS for autmake
     1.13 compat (817ea36)
   o Rename configure.in to configure.ac to appease newer autoconfs (0c79787)
   o Avoid using top_srcdir in TESTS: new automakes do not like this (a55514e)

 Bugfixes (resource leaks/lock errors on error, from 2.0)
   o Avoid leaking fds on evconnlistener with no callback set (69db261)
   o Avoid double-close on getsockname error in evutil_ersatz_socketpair
     (0a822a6)
   o Fix a locking error in bufferevent_socket_get_dns_error. (0a5eb2e)

 Documentation Fixes (from 2.0)
   o Fix a mistake in evbuffer_remove() arguments in example http server code
     (c322c20 Gyepi Sam)
   o Fix a typo in a comment in buffer.h. Spotted by Alt_F4 (773b0a5)

 Documentation Fixes
   o minor documentation typos (809586a Patrick Pelletier)
   o Fix cut-and-paste err in whatsnew-2.1 (49905ac)
   o Fix comment to refer to sample/include.am correctly (9e8cdf3 Sebastian
     Hahn)
   o Fix typo : Dispatching instead of Dispaching (0c2bacc Volker Lendecke)
   o fix some hinky indentation in evhttp_make_request (80e220e Patrick
     Pelletier)
   o "buffer" spelling (a452811 Patrick Pelletier)
   o Specify return behavior in header for evbuffer_pullup() in corner case
     (cf8d1cd Dan Petro)
   o Clarify an important point about event_base_foreach_event() (920a5e6)

 Compilation Fixes/Tool Support
   o avoid valgrind false positive by zeroing epoll_event (1258614 Patrick
     Pelletier)
   o Fix harmless clang enum warning (b452a43 Sebastian Hahn)
   o remove all exes on "make clean", not just regress.exe (974bfa0 Patrick
     Pelletier)
   o Make --disable-libevent-regress work again (787fd74)
   o Do not build strlcpy.c when it will have no code. (4914620)

 Portability Fixes
   o When EWOULDBLOCK is not EAGAIN, treat it as equivalent to it (bf7a0ff)
   o Preliminary changes for Minix3. (0dda56a Nicholas Heath)
   o Use AC_CONFIG_HEADERS in place of AM_CONFIG_HEADERS for autmake 1.13
     compat (bf278b)
   o Avoid using $(top_srcdir) in TESTS. (2863c83)
   o build test/test-script.sh on systems with a less-featureful $< (f935e21)
   o Implement EVUTIL_ERR_IS_EAGAIN on windows. (42aaf4d)

 Evhttp changes:
   o Fix ipv6 support for http. When URL contain domain, not IP
     address. (71e709c Azat Khuzhin)
   o uri decode: fix for warning "use of uninitialised value" (64b6ece Azat
     Khuzhin)
   o uri decode: changed the test for the existence of the next character
     (e1903e3 Azat Khuzhin)
   o Move prototype of evhttp_decode_uri_internal() to http-internal.h
     (de8101a Azat Khuzhin)
   o Test: decoding just part of string with evhttp_decode_uri_internal()
     (1367653 Azat Khuzhin)
   o Add new error_cb for actual reporting of HTTP request errors. (7b07719
     Azat Khuzhin)
   o Add test for EVREQ_HTTP_REQUEST_CANCEL into http_cancel_test() (862c217
     Azat Khuzhin)
   o Drop extra header http_struct.h from regress_http.c (54cc800 Azat Khuzhin)

 Testing
   o Add regress test ipv6_for_domain. (9ec88bd Azat Khuzhin)
   o Add an environment variable (EVENT_DEBUG_MODE) to run unit tests in debug
     mode (2fad0f3)
   o Add a test with an active_later event at event_base_free time. (1c3147f)
   o Make all tests pass under EVENT_DEBUG_MODE=1 (b1b054f)
   o Add some verbose notes to bufferevent unit tests (9d893c9)
   o New test for active_later->active transition on event_active (a153874)
   o New tests for event_base_foreach_event() (0b096ef)
   o Unit tests for event_base_gettimeofday_cached() and
     event_base_update_cache_time() (30ea291)
   o A test for event_get_assignment() (f09629e)
   o More unit tests for initializing common timeouts. (d596739)
   o Fix a bug in the new main/event_foreach test (702c9aa)

 Windows:
   o use FormatMessage for winsock errors (0c6ec5d, 2078e9b, 4ccdd53, c9ad3af
     Patrick Pelletier)
   o a program to print out the error strings for winsock errors (7296512
     Patrick Pelletier)
   o Fix a warning introduced in 0c6ec5d8 (eeb700c)
   o Fix another warning introduced in 0c6ec5d8 (ed26561)

 Examples (http)
   o Add sample/https-client.c, an example of stacking evhttp as a client on
     top of bufferevent_ssl. (be46c99 Catalin Patulea)
   o use ${OPENSSL_LIBS} instead of -lssl -lcrypto (bf31fa5 Patrick Pelletier)
   o https-client was putting newlines at 256-byte boundaries (42d7441 Patrick
     Pelletier)
   o better handling of OpenSSL errors (5754d96 Patrick Pelletier)
   o use Debian's default root certificate location (aacd674 Patrick Pelletier)
   o use iSECPartners code to validate hostname in certificate (64d9f16
     Patrick Pelletier)
   o avoid sign mismatch warning in openssl_hostname_validation.c (6021cb5
     Patrick Pelletier)
   o pull in wildcard matching code from cURL (4db9da6 Patrick Pelletier)
   o Another tweak to https-client.c (95acdaa)
   o Remove http_struct.h usage in sample/https-client.c (8a90a85)


Plans for Libevent 2.1
======================

There are a bunch more features I'd like to get into Libevent 2.1, but I
understand that people would like a stable release soon, and so would I. So
I'm going to give myself the month of May to see if I can get any more done,
and then start putting out release candidates.

Some features I'd _like_ to get done in 2.1 are:
  * UDP bufferevents.
  * An improved win32 backend, based on chrisd's hybrid-select work.
  * Drop-in support for better resolvers.
  * An NSPR-backed bufferevent implementation for people who prefer
    their TLS to be NSS-flavored.
  * A unified callback system so that bufferevent callbacks, event callbacks,
    evdns callbacks, evbuffer callbacks (and so on) can all use the same
    callback logic.
But of course, there's no way I can get this all done myself in a month.

Since Libevent 2.1 is in alpha, I'm going to continue taking bugfix
patches for 2.0, but I'm going to be even more strict about what counts
as a bugfix. I'm going to let 2.1.3-alpha sit out there for a while before
releasing the next 2.0, to try to make sure that none of bugfixes currently
pending for 2.0 are really regressions.

I expect Libevent 2.1 to be much less disruptive than Libevent 2.0 for
people who want to upgrade.  Nevertheless, I'm going to continue
supporting 2.0 for a good while after 2.1 becomes stable.

Acknowledgments
===============

Thanks to everybody who helped with code, bug reports, and suggestions,
including but not limited to:

Kevin Bowling
Hing Cheung
Tay Ray Chuan
Sebastian Hahn
Greg Hazel
Nicholas Heath
Xiuqiang Jiang
Azat Khuzhin
Volker Lendecke
Catalin Patulea
Patrick Pelletier
Dan Petro
Nate Rosenblum
Gyepi Sam
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