Added clear_sysy_exc_info to eventlet.common.

Portable clearing of last exception information - No-op in 3.x and ys.exc_clear in 2.x

eventlet/common.py

@@ -1,3 +1,4 @@
+import sys
 def get_errno(exc):
     """ Get the error code out of socket.error objects.
     socket.error in <2.5 does not have errno attribute
@@ -17,3 +18,11 @@ def get_errno(exc):
     except IndexError:
         return None
 
+if sys.version_info[0]<3:
+    clear_sys_exc_info = sys.exc_clear
+else:
+    def clear_sys_exc_info():
+        """No-op In py3k. 
+        Exception information is not visible outside of except statements.
+        sys.exc_clear became obsolete and removed."""
+        pass

eventlet/hubs/hub.py

@@ -2,18 +2,12 @@ import heapq
 import sys
 import traceback
 
+from eventlet.common import clear_sys_exc_info
 from eventlet.support import greenlets as greenlet
 from eventlet.hubs import timer
 from eventlet import patcher
 time = patcher.original('time')
 
-# In py3k exception information is not visible outside of except statements
-# so sys.exc_clear become obsolete and removed.
-try:
-   sys_exc_clear = sys.exc_clear
-except AttributeError:
-   sys_exc_clear = lambda: None
-
 READ="read"
 WRITE="write"
 
@@ -110,7 +104,7 @@ class BaseHub(object):
                 switch_out()
             except:
                 self.squelch_generic_exception(sys.exc_info())
-                sys.exc_clear()
+                clear_sys_exc_info()
         if self.greenlet.dead:
             self.greenlet = greenlet.greenlet(self.run)
         try:
@@ -118,7 +112,7 @@ class BaseHub(object):
                 cur.parent = self.greenlet
         except ValueError:
             pass  # gets raised if there is a greenlet parent cycle
-        sys_exc_clear()
+        clear_sys_exc_info()
         return self.greenlet.switch()
 
     def squelch_exception(self, fileno, exc_info):
@@ -257,7 +251,7 @@ class BaseHub(object):
                     raise
                 except:
                     self.squelch_timer_exception(timer, sys.exc_info())
-                    sys.exc_clear()
+                    clear_sys_exc_info()
             finally:
                 self.timer_finished(timer)
 

eventlet/hubs/selects.py

@@ -1,7 +1,7 @@
 import sys
 import errno
 from eventlet import patcher
-from eventlet.common import get_errno
+from eventlet.common import get_errno, clear_sys_exc_info
 select = patcher.original('select')
 time = patcher.original('time')
 
@@ -58,4 +58,4 @@ class Hub(BaseHub):
                     raise
                 except:
                     self.squelch_exception(fileno, sys.exc_info())
-                    sys.exc_clear()
+                    clear_sys_exc_info()

tests/test__refcount.py

@@ -4,6 +4,7 @@ are not leaked by the hub.
 import sys
 import unittest
 from pprint import pformat
+from eventlet.common import clear_sys_exc_info
 from eventlet.green import socket
 from eventlet.green.thread import start_new_thread
 from eventlet.green.time import sleep
@@ -61,7 +62,7 @@ def run_interaction(run_client):
 
 def run_and_check(run_client):
     w = run_interaction(run_client=run_client)
-    sys.exc_clear()
+    clear_sys_exc_info()
     if w():
         print pformat(gc.get_referrers(w()))
         for x in gc.get_referrers(w()):