In Modules/selectmodule.c it is assumed that the kevent structure is defined on FreeBSD and NetBSD as: struct kevent { uintptr_t ident; short filter; u_short flags; u_int fflags; intptr_t data; uintptr_t udata; }; and on OpenBSD as: struct kevent { u_int ident; short filter; u_short flags; u_int fflags; intptr_t data; int udata; }; Actually it is defined on FreeBSD as: struct kevent { uintptr_t ident; short filter; u_short flags; u_int fflags; intptr_t data; void *udata; }; On OpenBSD as: struct kevent { uintptr_t ident; short filter; u_short flags; u_int fflags; int64_t data; void *udata; }; And on NetBSD as: struct kevent { uintptr_t ident; uint32_t filter; uint32_t flags; uint32_t fflags; int64_t data; intptr_t udata; }; Other issues are related to rich comparison. Due to integer overflows the ordering is not transitive. The rich comparison protocol is not properly supported, comparing a kevent_event object with a non-kevent_event object don't falls back to the rich comparison methods of the right arguments.

 New changeset b9052a0f91d2e83bbc27267247a5920c82b242a3 by Serhiy Storchaka in branch 'master': bpo-31893: Fixed select.kqueue(). (#4166) https://github.com/python/cpython/commit/b9052a0f91d2e83bbc27267247a5920c82b242a3 

 New changeset f9a639b97c760f40d022223c7655053c89752850 by Serhiy Storchaka (Miss Islington (bot)) in branch '3.6': bpo-31893: Fixed select.kqueue(). (GH-4166) (#4190) https://github.com/python/cpython/commit/f9a639b97c760f40d022223c7655053c89752850 

The commit b9052a0f91d2e83bbc27267247a5920c82b242a3 broke compilation on FreeBSD: building 'select' extension cc -pthread -fPIC -Wno-unused-result -Wsign-compare -g -O0 -Wall -Wstrict-prototypes -std=c99 -Wextra -Wno-unused-result -Wno-unused-parameter -Wno-missing-field-initializers -Werror=implicit-function-declaration -I./Include -I. -I/usr/local/include -I/usr/home/buildbot/python/3.x.koobs-freebsd10/build/Include -I/usr/home/buildbot/python/3.x.koobs-freebsd10/build -c /usr/home/buildbot/python/3.x.koobs-freebsd10/build/Modules/selectmodule.c -o build/temp.freebsd-10.3-STABLE-amd64-3.7-pydebug/usr/home/buildbot/python/3.x.koobs-freebsd10/build/Modules/selectmodule.o /usr/home/buildbot/python/3.x.koobs-freebsd10/build/Modules/selectmodule.c:1889:63: error: expected ';' at end of declaration FILTER_FMT_UNIT FLAGS_FMT_UNIT FFLAGS_FMT_UNIT DATA_FMT_UNIT ^ ; 1 error generated. *** WARNING: renaming "_asyncio" since importing it failed: No module named 'select' http://buildbot.python.org/all/#/builders/87/builds/95/steps/3/logs/stdio

 New changeset 8cbf4e10646c3f5b8f0d274c2d7dea5bb6305f57 by Serhiy Storchaka in branch '2.7': [2.7] bpo-31893: Fixed select.kqueue(). (GH-4166) (#4193) https://github.com/python/cpython/commit/8cbf4e10646c3f5b8f0d274c2d7dea5bb6305f57 

Oh, the commit also broke the "x86 Tiger 3.x buildbot: http://buildbot.python.org/all/#/builders/30/builds/93 ====================================================================== FAIL: test_create_event (test.test_kqueue.TestKQueue) ---------------------------------------------------------------------- Traceback (most recent call last): File "/Users/db3l/buildarea/3.x.bolen-tiger/build/Lib/test/test_kqueue.py", line 71, in test_create_event self.assertEqual(ev.data, 5) AssertionError: 25769803781 != 5

Oh, I forgot that Mac OS X also in the BSD family. Thank you Victor for signaling errors.

 New changeset 2298fad5ff907dd48ea0fb5c71fa22334ef28c6b by Serhiy Storchaka in branch 'master': bpo-31893: Fix errors in b9052a0f91d2e83bbc27267247a5920c82b242a3. (#4196) https://github.com/python/cpython/commit/2298fad5ff907dd48ea0fb5c71fa22334ef28c6b 

 New changeset 84e252b79eed94bc9e9175f82191322c89e489ad by Serhiy Storchaka (Miss Islington (bot)) in branch '3.6': bpo-31893: Fix errors in b9052a0f91d2e83bbc27267247a5920c82b242a3. (GH-4196) (#4201) https://github.com/python/cpython/commit/84e252b79eed94bc9e9175f82191322c89e489ad 

 New changeset e7531e54bf195b8d3ed35b4138901c82f7ed794c by Serhiy Storchaka (Miss Islington (bot)) in branch '2.7': bpo-31893: Fix errors in b9052a0f91d2e83bbc27267247a5920c82b242a3. (GH-4196) (#4202) https://github.com/python/cpython/commit/e7531e54bf195b8d3ed35b4138901c82f7ed794c 

Tests on all buildbots are passed.

 New changeset ce51890894be46f8f9d991a1d0ea1455fc41ccdc by Serhiy Storchaka in branch '2.7': bpo-31893: Fix a backporting error in 8cbf4e10646c3f5b8f0d274c2d7dea5bb6305f57. (#4219) https://github.com/python/cpython/commit/ce51890894be46f8f9d991a1d0ea1455fc41ccdc 

Test fails on x86 Tiger 2.7: http://buildbot.python.org/all/#/builders/59/builds/17 ====================================================================== FAIL: test_create_event (test.test_kqueue.TestKQueue) ---------------------------------------------------------------------- Traceback (most recent call last): File "/Users/db3l/buildarea/2.7.bolen-tiger/build/Lib/test/test_kqueue.py", line 39, in test_create_event self.assertRaises(TypeError, cmp, ev, None) AssertionError: TypeError not raised

Same failure on x86-64 El Capitan 2.7/ http://buildbot.python.org/all/#builders/98/builds/17 ====================================================================== FAIL: test_create_event (test.test_kqueue.TestKQueue) ---------------------------------------------------------------------- Traceback (most recent call last): File "/Users/buildbot/buildarea/2.7.billenstein-elcapitan/build/Lib/test/test_kqueue.py", line 39, in test_create_event self.assertRaises(TypeError, cmp, ev, None) AssertionError: TypeError not raised

On also AMD64 FreeBSD 10.x Shared 2.7: http://buildbot.python.org/all/#/builders/97/builds/17 ====================================================================== FAIL: test_create_event (test.test_kqueue.TestKQueue) ---------------------------------------------------------------------- Traceback (most recent call last): File "/usr/home/buildbot/python/2.7.koobs-freebsd10/build/Lib/test/test_kqueue.py", line 39, in test_create_event self.assertRaises(TypeError, cmp, ev, None) AssertionError: TypeError not raised

Oh, I didn't test on 2.7. The old code contradicted the common comparison behavior. It allowed comparing select.kevent with other objects only for equality as for identity. `kevent == other` always returned False even if `other == kevent` returned True. `kevent < other` raised a TypeError. The new code uses the default behavior. `kevent == other` returns the same as `other == kevent` (False by default if types are not comparable, but may return True if `other.__eq__(kevent)` returns True). `kevent < other` returns the same as `other > kevent`. E.g. raises a TypeError by default in Python 3. But in Python 2 all objects are comparable by default, and this breaks a test which expects that select.kevent is not comparable. There are two ways to fix this: 1. Make select.kevent non-comparable again. This contradicts the default behavior and I don't know reasons why it should be non-comparable, but this was an existing behavior. 2. Remove the tests or change them to test that comparing select.kevent with other object doesn't raise an error.

kqueue_event_richcompare() returns NotImplemented if other is not an event: if (!kqueue_event_Check(o)) { Py_INCREF(Py_NotImplemented); return Py_NotImplemented; } So I don't understand why tests started to fail with the commit ce51890894be46f8f9d991a1d0ea1455fc41ccdc.

Because the default behavior is different in Python 2 and Python 3. In Python 3 this is a TypeError. In Python 2 all objects are comparable by default.

I suggest to fix the tests, the code looks good to me.

Fixed by PR 4349 (changeset 15e14538f90cabc87473a489316fdb81af76cfb2).