Backport fix for #835.

changelog.rst

@@ -10,6 +10,9 @@
 - Python 2: ``sendall`` on a non-blocking socket could spuriously fail
   with a timeout.
 - Fix :issue:`825`.
+- :class:`selectors.SelectSelector` is properly monkey-patched
+  regardless of the order of imports. Reported in :issue:`835` by
+  Przemysław Węgrzyn.
 
 1.1.1 (Apr 4, 2016)
 ===================

gevent/monkey.py

@@ -468,12 +468,18 @@ def patch_select(aggressive=True):
         # not a builtin and doesn't get the magic auto-static that they do)
         #    r, w, _ = self._select(self._readers, self._writers, [], timeout)
         #    TypeError: select() takes from 3 to 4 positional arguments but 5 were given
-        select = __import__('select')
+        # Note that this obviously only happens if selectors was imported after we had patched
+        # select; but there is a code path that leads to it being imported first (but now we've
+        # patched select---so we can't compare them identically)
+        select = __import__('select') # Should be gevent-patched now
+        orig_select_select = get_original('select', 'select')
+        assert select.select is not orig_select_select
         selectors = __import__('selectors')
-        if selectors.SelectSelector._select is select.select:
-            def _select(self, *args, **kwargs):
-                return select.select(*args, **kwargs)
-            selectors.SelectSelector._select = _select
+        if selectors.SelectSelector._select in (select.select, orig_select_select):
+             def _select(self, *args, **kwargs): # pylint:disable=unused-argument
+                 return select.select(*args, **kwargs)
+             selectors.SelectSelector._select = _select
+             _select._gevent_monkey = True
 
         if aggressive:
             # If `selectors` had already been imported before we removed

greentest/test__monkey_selectors.py

+import sys
+import greentest
+try:
+    import selectors # Do this before the patch, just to force it
+except ImportError:
+    pass
+from gevent.monkey import patch_all
+patch_all()
+
+if sys.platform != 'win32' and sys.version_info[:2] >= (3, 4):
+
+    class TestSelectors(greentest.TestCase):
+
+        def test_selectors_select_is_patched(self):
+            # https://github.com/gevent/gevent/issues/835
+            _select = selectors.SelectSelector._select
+            self.assertTrue(hasattr(_select, '_gevent_monkey'), dir(_select))
+
+
+if __name__ == '__main__':
+    greentest.main()