Fix #841

changelog.rst

@@ -85,6 +85,11 @@ Stdlib Compatibility
   and generally only exposes methods appropriate to the mode it is in.
 - ``FileObjectPosix`` supports a *bufsize* of 0 in binary write modes.
   Reported in :issue:`840` by Mike Lang.
+- Python 3: meth:`gevent.socket.connect_ex` was letting
+  ``BlockingIOError`` (and possibly others) get raised instead of
+  returning the errno due to the refactoring of the exception
+  hierarchy in Python 3.3. Now the errno is returned. Reported in
+  :issue:`841` by Dana Powers.
 
 Other Changes
 -------------

src/gevent/_socket3.py

@@ -307,11 +307,17 @@ class socket(object):
             return self.connect(address) or 0
         except timeout:
             return EAGAIN
+        except gaierror:
+            # gaierror/overflowerror/typerror is not silented by connect_ex;
+            # gaierror extends OSError (aka error) so catch it first
+            raise
         except error as ex:
-            if type(ex) is error: # pylint:disable=unidiomatic-typecheck
-                return ex.args[0]
-            else:
-                raise  # gaierror is not silented by connect_ex
+            # error is now OSError and it has various subclasses.
+            # Only those that apply to actually connecting are silenced by
+            # connect_ex.
+            if ex.errno:
+                return ex.errno
+            raise # pragma: no cover
 
     def recv(self, *args):
         while True:

src/greentest/test__socket.py

@@ -12,6 +12,7 @@ import _six as six
 # we use threading on purpose so that we can test both regular and gevent sockets with the same code
 from threading import Thread as _Thread
 
+errno_types = int
 
 def wrap_error(func):
 
@@ -261,6 +262,28 @@ class TestTCP(greentest.TestCase):
 
         s.close()
 
+    def test_connect_ex_nonblocking_bad_connection(self):
+        # Issue 841
+        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        s.setblocking(False)
+        ret = s.connect_ex(('localhost', get_port()))
+        self.assertIsInstance(ret, errno_types)
+        s.close()
+
+    def test_connect_ex_gaierror(self):
+        # Issue 841
+        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        with self.assertRaises(socket.gaierror):
+            s.connect_ex(('foo.bar.fizzbuzz', get_port()))
+        s.close()
+
+    def test_connect_ex_nonblocking_overflow(self):
+        # Issue 841
+        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        s.setblocking(False)
+        with self.assertRaises(OverflowError):
+            s.connect_ex(('localhost', 65539))
+        s.close()
 
 def get_port():
     tempsock = socket.socket()