Fix built-in gevent tests for Python 3.10

docs/changes/1790.feature

@@ -3,3 +3,5 @@ Add support for Python 3.10.
 As part of this, the minimum required greenlet version was increased
 to 1.1.0 (on CPython), and the minimum version of Cython needed to
 build gevent from a source checkout is 3.0a9.
+
+Note that the dnspython resolver is not available on Python 3.10.

docs/install.rst

@@ -71,7 +71,10 @@ supported.
 |       |       |
 |       |       |
 +-------+-------+
-
+|3.5.x  | 20.9.0|
+|       |       |
+|       |       |
++-------+-------+
 
 Installation
 ============
@@ -145,11 +148,13 @@ events
     will be removed in gevent 21.0.
 
 dnspython
-    Enables the new pure-Python resolver, backed by `dnspython
+    Enables a pure-Python resolver, backed by `dnspython
     <https://pypi.org/project/dnspython>`_. On Python 2, this also
     includes `idna <https://pypi.org/project/idna>`_. They can be
     installed with the ``dnspython`` extra.
 
+    .. note:: This is not compatible with Python 3.10 or dnspython 2.
+
 monitor
     Enhancements to gevent's self-monitoring capabilities. This
     includes the `psutil <https://pypi.org/project/psutil>`_ library

setup.py

@@ -299,8 +299,10 @@ del _to_cythonize
 ## Extras
 
 EXTRA_DNSPYTHON = [
-    'dnspython >= 1.16.0, < 2.0',
-    'idna',
+    # We're not currently compatible with 2.0, and dnspython 1.x isn't
+    # compatible weth Python 3.10 because of the removal of ``collections.MutableMapping``.
+    'dnspython >= 1.16.0, < 2.0; python_version < "3.10"',
+    'idna; python_version < "3.10"',
 ]
 EXTRA_EVENTS = [
     # No longer does anything, but the extra must stay around

src/gevent/testing/__init__.py

@@ -82,6 +82,7 @@ from .sysinfo import RUNNING_ON_CI
 from .sysinfo import RESOLVER_NOT_SYSTEM
 from .sysinfo import RESOLVER_DNSPYTHON
 from .sysinfo import RESOLVER_ARES
+from .sysinfo import resolver_dnspython_available
 
 from .sysinfo import EXPECT_POOR_TIMER_RESOLUTION
 
@@ -107,6 +108,7 @@ from .skipping import skipOnPurePython
 from .skipping import skipWithCExtensions
 from .skipping import skipOnLibuvOnTravisOnCPython27
 from .skipping import skipOnPy37
+from .skipping import skipOnPy310
 from .skipping import skipOnPy3
 from .skipping import skipWithoutResource
 from .skipping import skipWithoutExternalNetwork

src/gevent/testing/skipping.py

@@ -48,6 +48,7 @@ skipOnPyPyOnWindows = _do_not_skip
 skipOnPy2 = unittest.skip if sysinfo.PY2 else _do_not_skip
 skipOnPy3 = unittest.skip if sysinfo.PY3 else _do_not_skip
 skipOnPy37 = unittest.skip if sysinfo.PY37 else _do_not_skip
+skipOnPy310 = unittest.skip if sysinfo.PY310 else _do_not_skip
 
 skipOnPurePython = unittest.skip if sysinfo.PURE_PYTHON else _do_not_skip
 skipWithCExtensions = unittest.skip if not sysinfo.PURE_PYTHON else _do_not_skip

src/gevent/testing/sysinfo.py

@@ -66,6 +66,7 @@ PY36 = None
 PY37 = None
 PY38 = None
 PY39 = None
+PY310 = None
 
 NON_APPLICABLE_SUFFIXES = ()
 if sys.version_info[0] >= 3:
@@ -83,6 +84,8 @@ if sys.version_info[0] >= 3:
         PY38 = True
     if sys.version_info[1] >= 9:
         PY39 = True
+    if sys.version_info[1] >= 10:
+        PY310 = True
 
 elif sys.version_info[0] == 2:
     # Any python 2
@@ -188,3 +191,12 @@ def libev_supports_linux_iouring():
     from platform import release
 
     return system() == 'Linux' and LooseVersion(release() or '0') >= LooseVersion('5.3')
+
+def resolver_dnspython_available():
+    # Try hard not to leave around junk we don't have to.
+    import pkg_resources
+    try:
+        pkg_resources.get_distribution('dnspython')
+    except pkg_resources.DistributionNotFound:
+        return False
+    return True

src/gevent/testing/util.py

@@ -246,7 +246,7 @@ def start(command, quiet=False, **kwargs):
     if timeout is not None:
         t = get_original('threading', 'Timer')(timeout, kill, args=(popen, ))
         popen.timer = t
-        t.setDaemon(True)
+        t.daemon = True
         t.start()
         popen.timer = t
     return popen

src/gevent/tests/test__hub.py

@@ -146,6 +146,8 @@ class TestPeriodicMonitoringThread(greentest.TestCase):
         super(TestPeriodicMonitoringThread, self).setUp()
         self.monitor_thread = gevent.config.monitor_thread
         gevent.config.monitor_thread = True
+        from gevent.monkey import get_original
+        self.lock = get_original('threading', 'Lock')()
         self.monitor_fired = 0
         self.monitored_hubs = set()
         self._reset_hub()
@@ -162,9 +164,10 @@ class TestPeriodicMonitoringThread(greentest.TestCase):
         super(TestPeriodicMonitoringThread, self).tearDown()
 
     def _monitor(self, hub):
-        self.monitor_fired += 1
-        if self.monitored_hubs is not None:
-            self.monitored_hubs.add(hub)
+        with self.lock:
+            self.monitor_fired += 1
+            if self.monitored_hubs is not None:
+                self.monitored_hubs.add(hub)
 
     def test_config(self):
         self.assertEqual(0.1, gevent.config.max_blocking_time)
@@ -177,7 +180,7 @@ class TestPeriodicMonitoringThread(greentest.TestCase):
 
         def monitor_cond(_hub):
             cond.acquire()
-            cond.notifyAll()
+            cond.notify_all()
             cond.release()
             if kill:
                 # Only run once. Especially helpful on PyPy, where
@@ -245,15 +248,29 @@ class TestPeriodicMonitoringThread(greentest.TestCase):
         threadpool = hub.threadpool
 
         worker_hub = threadpool.apply(get_hub)
-        stream = worker_hub.exception_stream = NativeStrIO()
+        assert hub is not worker_hub
+        stream = NativeStrIO()
 
         # It does not have a monitoring thread yet
         self.assertIsNone(worker_hub.periodic_monitoring_thread)
-        # So switch to it and give it one.
-        threadpool.apply(gevent.sleep, (0.01,))
-        self.assertIsNotNone(worker_hub.periodic_monitoring_thread)
-        worker_monitor = worker_hub.periodic_monitoring_thread
-        worker_monitor.add_monitoring_function(self._monitor, 0.1)
+        # So switch to it and give it one by letting it run.
+        # XXX: Python 3.10 appears to have made some changes in the memory model.
+        # Specifically, reading values from the background that are set in the
+        # background hub *from this thread* is flaky. It takes them awhile to show up.
+        # Really, that's correct and expected from a standard C point of view, as we
+        # don't insert any memory barriers or things like that. It just always used to
+        # work in the past. So now, rather than read them directly, we need to read them
+        # from the background thread itself. The same, apparently, goes for
+        # writing.
+        # Need to figure out what exactly the change was.
+        def task():
+            get_hub().exception_stream = stream
+            gevent.sleep(0.01)
+            mon = get_hub().periodic_monitoring_thread
+            mon.add_monitoring_function(self._monitor, 0.1)
+            return mon
+        worker_monitor = threadpool.apply(task)
+        self.assertIsNotNone(worker_monitor)
 
         return worker_hub, stream, worker_monitor
 
@@ -272,8 +289,9 @@ class TestPeriodicMonitoringThread(greentest.TestCase):
 
         # We did run the monitor in the worker thread, but it
         # did NOT report itself blocked by the worker thread sitting there.
-        self.assertIn(worker_hub, self.monitored_hubs)
-        self.assertEqual(stream.getvalue(), '')
+        with self.lock:
+            self.assertIn(worker_hub, self.monitored_hubs)
+            self.assertEqual(stream.getvalue(), '')
 
     @greentest.ignores_leakcheck
     def test_blocking_threadpool_thread_one_greenlet(self):
@@ -295,8 +313,9 @@ class TestPeriodicMonitoringThread(greentest.TestCase):
 
         # We did run the monitor in the worker thread, but it
         # did NOT report itself blocked by the worker thread
-        self.assertIn(worker_hub, self.monitored_hubs)
-        self.assertEqual(stream.getvalue(), '')
+        with self.lock:
+            self.assertIn(worker_hub, self.monitored_hubs)
+            self.assertEqual(stream.getvalue(), '')
 
 
     @greentest.ignores_leakcheck

src/gevent/tests/test__resolver_dnspython.py

@@ -14,6 +14,8 @@ import os
 
 from gevent import testing as greentest
 
+@unittest.skipUnless(greentest.resolver_dnspython_available(),
+                     "dnspython not available")
 class TestDnsPython(unittest.TestCase):
 
     def _run_one(self, mod_name):

src/gevent/tests/test__ssl.py

@@ -98,6 +98,7 @@ class TestSSL(test__socket.TestTCP):
     #         raise
 
     @greentest.ignores_leakcheck
+    @greentest.skipOnPy310("No longer raises SSLError")
     def test_empty_send(self):
         # Issue 719
         # Sending empty bytes with the 'send' method raises

src/gevent/tests/test__threading.py

@@ -13,7 +13,7 @@ import threading
 
 
 def helper():
-    threading.currentThread()
+    threading.current_thread()
     gevent.sleep(0.2)
 
 

src/gevent/tests/test__threading_2.py

@@ -145,13 +145,13 @@ class ThreadTests(unittest.TestCase):
         # The ident still must work for the main thread and dummy threads,
         # as must the repr and str.
 
-        t = threading.currentThread()
+        t = threading.current_thread()
         self.assertFalse(t.ident is None)
         str(t)
         repr(t)
 
         def f():
-            t = threading.currentThread()
+            t = threading.current_thread()
             ident.append(t.ident)
             str(t)
             repr(t)

src/gevent/tests/test__threading_vs_settrace.py

@@ -25,7 +25,7 @@ t.start()
 
 def trace(frame, event, arg):
     if threading is not None:
-        threading.currentThread()
+        threading.current_thread()
     return trace