* bpo-34130: Fix test_signal.test_socket() (GH-8326)
test_signal.test_socket(): On Windows, sometimes even if the C signal handler
succeed to write the signal number into the write end of the socketpair, the
test fails with a BlockingIOError on the non-blocking read.recv(1) because the
read end of the socketpair didn't receive the byte yet.
Fix the race condition on Windows by setting the read end as blocking.
(cherry picked from commit 99bb6df66a)
* bpo-34130: Fix test_signal.test_warn_on_full_buffer() (GH-8327)
On Windows, sometimes test_signal.test_warn_on_full_buffer() fails to
fill the socketpair buffer. In that case, the C signal handler
succeed to write into the socket, it doesn't log the expected send
error, and so the test fail.
On Windows, the test now uses a timeout of 50 ms to fill the
socketpair buffer to fix this race condition.
Other changes:
* Begin with large chunk size to fill the buffer to speed up the
test.
* Add error messages to assertion errors to more easily identify
which assertion failed.
* Don't set the read end of the socketpair as non-blocking.
(cherry picked from commit 686b4b5ff2)
* bpo-30796: Fix failures in signal delivery stress test
setitimer() can have a poor minimum resolution on some machines,
this would make the test reach its deadline (and a stray signal
could then kill a subsequent test).
* Make sure to clear the itimer after the test
* Improve signal delivery
Avoid using Py_AddPendingCall from signal handler, to avoid calling signal-unsafe functions.
* Remove unused function
* Improve comments
* Add stress test
* Adapt for --without-threads
* Add second stress test
* Add NEWS blurb
* Address comments @haypo
* Add Lib/test/signalinterproctester.py
* Don't disable the garbage collector anymore
* Don't use os.fork() with a subprocess to not inherit existing signal handlers
or threads: start from a fresh process
* Don't use UNIX kill command to send a signal but Python os.kill()
* Use a timeout of 10 seconds to wait for the signal instead of 1 second
* Always use signal.pause(), instead of time.wait(1), to wait for a signal
* Use context manager on subprocess.Popen
* remove code to retry on EINTR: it's no more needed since the PEP 475
* remove unused function exit_subprocess()
* Cleanup the code
I have compared output between pre- and post-patch runs of these tests
to make sure there's nothing missing and nothing broken, on both
Windows and Linux. The only differences I found were actually tests
that were previously *not* run.
when interrupted by a signal not in the *sigset* parameter, if the signal
handler does not raise an exception. signal.sigtimedwait() recomputes the
timeout with a monotonic clock when it is retried.
Remove test_signal.test_sigwaitinfo_interrupted() because sigwaitinfo() doesn't
raise InterruptedError anymore if it is interrupted by a signal not in its
sigset parameter.
retried with the recomputed delay, except if the signal handler raises an
exception (PEP 475).
Modify also test_signal to use a monotonic clock instead of the system clock.
- Use _testcapi.raise_signal() in test_signal
- close also os.pipe() file descriptors in some test_signal tests where they
were not closed properly
- Remove faulthandler._sigill() and faulthandler._sigbus(): reuse
_testcapi.raise_signal() in test_faulthandler