New submission from Kay F. Jahnke <k_...@web.de>:
scheduler uses heapq to schedule it's events. Heapq uses plain >/<
comparisons on the events. Now that comparisons of incomparable data
are no longer valid, the comparison fails if two events are scheduled
for the same time with the same priority, since the comparison
continues with comparing the 'action' components ov the event's tuple.
I suppose this behaviour is unwanted - at least I did not expect it and
it took me some time to figure out what it was due to. I worked around
it by assigning comparison functions to the event data type - since
this is part of the standard library, maybe a general fix should be
considered? Here's my humble snippet of code:
def evtlt ( self , other ):
if self.time < other.time:
return True
elif self.time == other.time:
return self.priority < other.priority
return False
sched.Event.__lt__ = evtlt
def evtgt ( self , other ):
if self.time > other.time:
return True
elif self.time == other.time:
return self.priority > other.priority
return False
sched.Event.__gt__ = evtgt
If anyone would care to reproduce the (?)bug, try:
import sched
def foo():
pass
def bar():
pass
s = sched.scheduler(None, None)
s.enterabs ( 0 , 0 , foo , () )
s.enterabs ( 0 , 0 , bar , () )
this produces the following output:
Traceback (most recent call last):
File "./schedbug.py", line 12, in <module>
s.enterabs ( 0 , 0 , bar , () )
File "c:\Programme\Python3.0\lib\sched.py", line 54, in enterabs
heapq.heappush(self._queue, event)
TypeError: unorderable types: function() < function()
----------
components: Library (Lib)
messages: 86408
nosy: kfj
severity: normal
status: open
title: heapq item comparison problematic with sched's events
type: behavior
versions: Python 3.0
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Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue5830>
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