[Python-checkins] python/dist/src/Lib threading.py,1.43,1.44

Wed Jul 21 04:22:00 CEST 2004

Update of /cvsroot/python/python/dist/src/Lib
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv25825/Lib
Modified Files:
	threading.py 
Log Message:
Fix bug where a KeyError was raised if -O was being used for the interpreter
and Thread.__delete() was called after a Thread instance was created. Problem
resulted from a currentThread() call in an 'assert' statement being optimized
out and dummy_thread.get_ident() always returning -1 and thus overwriting the
entry for the _MainThread() instance created in 'threading' at import time.
Closes bug #993394.
Index: threading.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/threading.py,v
retrieving revision 1.43
retrieving revision 1.44
diff -C2 -d -r1.43 -r1.44
*** threading.py	14 Jul 2004 19:07:15 -0000	1.43
--- threading.py	21 Jul 2004 02:21:57 -0000	1.44
***************
*** 494,499 ****

 def __delete(self):
 _active_limbo_lock.acquire()
! del _active[_get_ident()]
 _active_limbo_lock.release()

--- 494,531 ----

 def __delete(self):
+ """Remove the current thread from the dict of currently running
+ threads.
+ 
+ Must take care to not raise an exception if dummy_thread is being used
+ (and thus this module is being used as an instance of dummy_threading).
+ Since dummy_thread.get_ident() always returns -1 since there is only one
+ thread if dummy_thread is being used. This means that if any Thread
+ instances are created they will overwrite any other threads registered.
+ 
+ This is an issue with this method, though, since an instance of
+ _MainThread is always created by 'threading'. This gets overwritten the
+ instant an instance of Thread is created; both threads will have -1 as
+ their value from dummy_thread.get_ident() and thus have the same key in
+ the dict. This means that when the _MainThread instance created by
+ 'threading' tries to clean itself up when atexit calls this method it
+ gets a key error if another Thread instance was created since that
+ removed the only thing with the key of -1.
+ 
+ This all means that KeyError from trying to delete something from
+ _active if dummy_threading is being used is a red herring. But since
+ it isn't if dummy_threading is *not* being used then don't hide the
+ exception. Also don't need to worry about issues from interpreter
+ shutdown and sys not being defined because the call is protected by a
+ blanket try/except block where that could be a problem.
+ 
+ """
 _active_limbo_lock.acquire()
! if _sys.modules.has_key('dummy_threading'):
! try:
! del _active[_get_ident()]
! except KeyError:
! pass
! else:
! del _active[_get_ident()]
 _active_limbo_lock.release()