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changeset: 95315:76d297869859 user: Victor Stinner victor.stinner@gmail.com date: Tue Mar 31 12:08:09 2015 +0200 files: Doc/library/selectors.rst Lib/test/test_selectors.py description: Issue #23485: Enhance and update selectors doc and test_selectors Selector.select() is now retried with the recomputed timeout when interrupted by a signal. Write an unit test with a signal handler raising an exception, and a unit with a signal handler which does not raise an exception (it does nothing). diff -r f54bc2c52dfd -r 76d297869859 Doc/library/selectors.rst --- a/Doc/library/selectors.rst Tue Mar 31 12:10:33 2015 +0200 +++ b/Doc/library/selectors.rst Tue Mar 31 12:08:09 2015 +0200 @@ -159,6 +159,12 @@ timeout has elapsed if the current process receives a signal: in this case, an empty list will be returned. + .. versionchanged:: 3.5 + The selector is now retried with a recomputed timeout when interrupted + by a signal if the signal handler did not raise an exception (see + :pep:`475` for the rationale), instead of returning an empty list + of events before the timeout. + .. method:: close() Close the selector. diff -r f54bc2c52dfd -r 76d297869859 Lib/test/test_selectors.py --- a/Lib/test/test_selectors.py Tue Mar 31 12:10:33 2015 +0200 +++ b/Lib/test/test_selectors.py Tue Mar 31 12:08:09 2015 +0200 @@ -357,7 +357,35 @@ @unittest.skipUnless(hasattr(signal, "alarm"), "signal.alarm() required for this test") - def test_select_interrupt(self): + def test_select_interrupt_exc(self): + s = self.SELECTOR() + self.addCleanup(s.close) + + rd, wr = self.make_socketpair() + + class InterruptSelect(Exception): + pass + + def handler(*args): + raise InterruptSelect + + orig_alrm_handler = signal.signal(signal.SIGALRM, handler) + self.addCleanup(signal.signal, signal.SIGALRM, orig_alrm_handler) + self.addCleanup(signal.alarm, 0) + + signal.alarm(1) + + s.register(rd, selectors.EVENT_READ) + t = time() + # select() is interrupted by a signal which raises an exception + with self.assertRaises(InterruptSelect): + s.select(30) + # select() was interrupted before the timeout of 30 seconds + self.assertLess(time() - t, 5.0) + + @unittest.skipUnless(hasattr(signal, "alarm"), + "signal.alarm() required for this test") + def test_select_interrupt_noraise(self): s = self.SELECTOR() self.addCleanup(s.close) @@ -371,8 +399,11 @@ s.register(rd, selectors.EVENT_READ) t = time() - self.assertFalse(s.select(2)) - self.assertLess(time() - t, 2.5) + # select() is interrupted by a signal, but the signal handler doesn't + # raise an exception, so select() should by retries with a recomputed + # timeout + self.assertFalse(s.select(1.5)) + self.assertGreaterEqual(time() - t, 1.0) class ScalableSelectorMixIn: /victor.stinner@gmail.com