Fix EPROTOTYPE race condition on macOS [supersedes #1033]

src/gevent/_socket2.py

@@ -322,7 +322,7 @@ class socket(object):
         try:
             return sock.send(data, flags)
         except error as ex:
-            if ex.args[0] != EWOULDBLOCK or timeout == 0.0:
+            if ex.args[0] not in _socketcommon.GSENDAGAIN or timeout == 0.0:
                 raise
             sys.exc_clear()
             self._wait(self._write_event)

src/gevent/_socket3.py

@@ -389,7 +389,7 @@ class socket(object):
         try:
             return _socket.socket.send(self._sock, data, flags)
         except error as ex:
-            if ex.args[0] != EWOULDBLOCK or timeout == 0.0:
+            if ex.args[0] not in _socketcommon.GSENDAGAIN or timeout == 0.0:
                 raise
             self._wait(self._write_event)
             try:

src/gevent/_socketcommon.py

@@ -78,6 +78,8 @@ from gevent._util import copy_globals
 from gevent._util import _NONE
 
 is_windows = sys.platform == 'win32'
+is_macos = sys.platform == 'darwin'
+
 # pylint:disable=no-name-in-module,unused-import
 if is_windows:
     # no such thing as WSAEPERM or error code 10001 according to winsock.h or MSDN
@@ -102,6 +104,17 @@ try:
 except ImportError:
     EBADF = 9
 
+# macOS can return EPROTOTYPE when writing to a socket that is shutting
+# Down. Retrying the write should return the expected EPIPE error.
+# Downstream classes (like pywsgi) know how to handle/ignore EPIPE.
+# This set is used by socket.send() to decide whether the write should
+# be retried. The default is to retry only on EWOULDBLOCK. Here we add
+# EPROTOTYPE on macOS to handle this platform-specific race condition.
+GSENDAGAIN = (EWOULDBLOCK,)
+if is_macos:
+    from errno import EPROTOTYPE
+    GSENDAGAIN += (EPROTOTYPE,)
+
 import _socket
 _realsocket = _socket.socket
 import socket as __socket__