Diff for socket.connect_ex to returning EALREADY when a socket connection is already in progress

socket-EALREADY.diff

diff -r 03f797ecd7ea Lib/_socket.py
--- a/Lib/_socket.py	Thu Nov 12 13:47:41 2015 +1100
+++ b/Lib/_socket.py	Fri Nov 13 15:08:47 2015 -0700
@@ -28,7 +28,8 @@
 from java.util import NoSuchElementException
 from java.util.concurrent import (
     ArrayBlockingQueue, CopyOnWriteArrayList, CountDownLatch, LinkedBlockingQueue,
-    RejectedExecutionException, ThreadFactory, TimeUnit)
+    ExecutionException, RejectedExecutionException, ThreadFactory,
+    TimeoutException, TimeUnit)
 from java.util.concurrent.atomic import AtomicBoolean, AtomicLong
 from javax.net.ssl import SSLPeerUnverifiedException, SSLException
 
@@ -852,7 +853,7 @@
 
         if self.bind_addr:
             log.debug("Connect %s to %s", self.bind_addr, addr, extra={"sock": self})
-            bind_future = bootstrap.bind(self.bind_addr)
+            bind_future = bootstrap.bind(self.bind_addr).sync()
             self._handle_channel_future(bind_future, "local bind")
             self.channel = bind_future.channel()
         else:
@@ -888,16 +889,39 @@
             log.debug("Completed connection to %s", addr, extra={"sock": self})
 
     def connect_ex(self, addr):
+        was_connecting = self.connected  # actually means self.connecting if
+                                         # not blocking
         if not self.connected:
             try:
                 self.connect(addr)
             except error as e:
                 return e.errno
         if not self.connect_future.isDone():
-            return errno.EINPROGRESS
+            if was_connecting:
+                try:
+                    # Timing is based on CPython and was empirically
+                    # guestimated. Of course this means user code is
+                    # polling, so the the best we can do is wait like
+                    # this in supposedly nonblocking mode without
+                    # completely busy waiting!
+                    self.connect_future.get(1500, TimeUnit.MICROSECONDS)
+                except ExecutionException:
+                    # generally raised if closed; pick up the state
+                    # when testing for success
+                    pass
+                except TimeoutException:
+                    # more than 1.5ms, will report EALREADY below
+                    pass
+
+        if not self.connect_future.isDone():
+            if was_connecting:
+                return errno.EALREADY
+            else:
+                return errno.EINPROGRESS
         elif self.connect_future.isSuccess():
             return errno.EISCONN
         else:
+            print self.connect_future.cause()
             return errno.ENOTCONN
 
     # SERVER METHODS