Issue #22018: On Windows, signal.set_wakeup_fd() now also supports sockets.

A side effect is that Python depends to the WinSock library.

Lib/test/test_signal.py

@@ -6,6 +6,7 @@ import gc
 import pickle
 import select
 import signal
+import socket
 import struct
 import subprocess
 import traceback
@@ -255,6 +256,13 @@ class WakeupFDTests(unittest.TestCase):
         self.assertRaises((ValueError, OSError),
                           signal.set_wakeup_fd, fd)
 
+    def test_invalid_socket(self):
+        sock = socket.socket()
+        fd = sock.fileno()
+        sock.close()
+        self.assertRaises((ValueError, OSError),
+                          signal.set_wakeup_fd, fd)
+
     def test_set_wakeup_fd_result(self):
         r1, w1 = os.pipe()
         self.addCleanup(os.close, r1)
@@ -268,6 +276,20 @@ class WakeupFDTests(unittest.TestCase):
         self.assertEqual(signal.set_wakeup_fd(-1), w2)
         self.assertEqual(signal.set_wakeup_fd(-1), -1)
 
+    def test_set_wakeup_fd_socket_result(self):
+        sock1 = socket.socket()
+        self.addCleanup(sock1.close)
+        fd1 = sock1.fileno()
+
+        sock2 = socket.socket()
+        self.addCleanup(sock2.close)
+        fd2 = sock2.fileno()
+
+        signal.set_wakeup_fd(fd1)
+        self.assertIs(signal.set_wakeup_fd(fd2), fd1)
+        self.assertIs(signal.set_wakeup_fd(-1), fd2)
+        self.assertIs(signal.set_wakeup_fd(-1), -1)
+
 
 @unittest.skipIf(sys.platform == "win32", "Not valid on Windows")
 class WakeupSignalTests(unittest.TestCase):
@@ -435,6 +457,90 @@ class WakeupSignalTests(unittest.TestCase):
         """,  signal.SIGUSR1, signal.SIGUSR2, ordered=False)
 
 
+@unittest.skipUnless(hasattr(socket, 'socketpair'), 'need socket.socketpair')
+class WakeupSocketSignalTests(unittest.TestCase):
+
+    @unittest.skipIf(_testcapi is None, 'need _testcapi')
+    def test_socket(self):
+        # use a subprocess to have only one thread
+        code = """if 1:
+        import signal
+        import socket
+        import struct
+        import _testcapi
+
+        signum = signal.SIGINT
+        signals = (signum,)
+
+        def handler(signum, frame):
+            pass
+
+        signal.signal(signum, handler)
+
+        read, write = socket.socketpair()
+        read.setblocking(False)
+        write.setblocking(False)
+        signal.set_wakeup_fd(write.fileno())
+
+        _testcapi.raise_signal(signum)
+
+        data = read.recv(1)
+        if not data:
+            raise Exception("no signum written")
+        raised = struct.unpack('B', data)
+        if raised != signals:
+            raise Exception("%r != %r" % (raised, signals))
+
+        read.close()
+        write.close()
+        """
+
+        assert_python_ok('-c', code)
+
+    @unittest.skipIf(_testcapi is None, 'need _testcapi')
+    def test_send_error(self):
+        # Use a subprocess to have only one thread.
+        if os.name == 'nt':
+            action = 'send'
+        else:
+            action = 'write'
+        code = """if 1:
+        import errno
+        import signal
+        import socket
+        import sys
+        import time
+        import _testcapi
+        from test.support import captured_stderr
+
+        signum = signal.SIGINT
+
+        def handler(signum, frame):
+            pass
+
+        signal.signal(signum, handler)
+
+        read, write = socket.socketpair()
+        read.setblocking(False)
+        write.setblocking(False)
+
+        signal.set_wakeup_fd(write.fileno())
+
+        # Close sockets: send() will fail
+        read.close()
+        write.close()
+
+        with captured_stderr() as err:
+            _testcapi.raise_signal(signum)
+
+        err = err.getvalue()
+        if ('Exception ignored when trying to {action} to the signal wakeup fd'
+            not in err):
+            raise AssertionError(err)
+        """.format(action=action)
+        assert_python_ok('-c', code)
+
+
 @unittest.skipIf(sys.platform == "win32", "Not valid on Windows")
 class SiginterruptTest(unittest.TestCase):
 
@@ -984,6 +1090,7 @@ def test_main():
     try:
         support.run_unittest(GenericTests, PosixTests, InterProcessSignalTests,
                              WakeupFDTests, WakeupSignalTests,
+                             WakeupSocketSignalTests,
                              SiginterruptTest, ItimerTest, WindowsSignalTests,
                              PendingSignalsTests)
     finally: