Issue #16641: Fix default values of sched.scheduler.enter arguments were modifiable.
diff --git a/Doc/library/sched.rst b/Doc/library/sched.rst
index f6bd43f..e73ba40 100644
--- a/Doc/library/sched.rst
+++ b/Doc/library/sched.rst
@@ -36,19 +36,22 @@
>>> import sched, time
>>> s = sched.scheduler(time.time, time.sleep)
- >>> def print_time(): print("From print_time", time.time())
+ >>> def print_time(a='default'):
+ ... print("From print_time", time.time(), a)
...
>>> def print_some_times():
... print(time.time())
- ... s.enter(5, 1, print_time, ())
- ... s.enter(10, 1, print_time, ())
+ ... s.enter(10, 1, print_time)
+ ... s.enter(5, 2, print_time, argument=('positional',))
+ ... s.enter(5, 1, print_time, kwargs={'a': 'keyword'})
... s.run()
... print(time.time())
...
>>> print_some_times()
930343690.257
- From print_time 930343695.274
- From print_time 930343700.273
+ From print_time 930343695.274 positional
+ From print_time 930343695.275 keyword
+ From print_time 930343700.273 default
930343700.276
.. _scheduler-objects:
@@ -59,7 +62,7 @@
:class:`scheduler` instances have the following methods and attributes:
-.. method:: scheduler.enterabs(time, priority, action, argument=[], kwargs={})
+.. method:: scheduler.enterabs(time, priority, action, argument=(), kwargs={})
Schedule a new event. The *time* argument should be a numeric type compatible
with the return value of the *timefunc* function passed to the constructor.
@@ -67,8 +70,10 @@
*priority*.
Executing the event means executing ``action(*argument, **kwargs)``.
- *argument* must be a sequence holding the parameters for *action*.
- *kwargs* must be a dictionary holding the keyword parameters for *action*.
+ Optional *argument* argument must be a sequence holding the parameters
+ for *action* if any used.
+ Optional *kwargs* argument must be a dictionary holding the keyword
+ parameters for *action* if any used.
Return value is an event which may be used for later cancellation of the event
(see :meth:`cancel`).
@@ -80,7 +85,7 @@
*kwargs* parameter was added.
-.. method:: scheduler.enter(delay, priority, action, argument=[], kwargs={})
+.. method:: scheduler.enter(delay, priority, action, argument=(), kwargs={})
Schedule an event for *delay* more time units. Other than the relative time, the
other arguments, the effect and the return value are the same as those for
diff --git a/Lib/sched.py b/Lib/sched.py
index e523bc1..4b1f7ac 100644
--- a/Lib/sched.py
+++ b/Lib/sched.py
@@ -50,6 +50,8 @@
def __gt__(s, o): return (s.time, s.priority) > (o.time, o.priority)
def __ge__(s, o): return (s.time, s.priority) >= (o.time, o.priority)
+_sentinel = object()
+
class scheduler:
def __init__(self, timefunc=_time, delayfunc=time.sleep):
@@ -60,19 +62,21 @@
self.timefunc = timefunc
self.delayfunc = delayfunc
- def enterabs(self, time, priority, action, argument=[], kwargs={}):
+ def enterabs(self, time, priority, action, argument=(), kwargs=_sentinel):
"""Enter a new event in the queue at an absolute time.
Returns an ID for the event which can be used to remove it,
if necessary.
"""
+ if kwargs is _sentinel:
+ kwargs = {}
with self._lock:
event = Event(time, priority, action, argument, kwargs)
heapq.heappush(self._queue, event)
return event # The ID
- def enter(self, delay, priority, action, argument=[], kwargs={}):
+ def enter(self, delay, priority, action, argument=(), kwargs=_sentinel):
"""A variant that specifies the time as a relative time.
This is actually the more commonly used interface.
diff --git a/Misc/NEWS b/Misc/NEWS
index ce906a0..3317f68 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -124,6 +124,9 @@
Library
-------
+- Issue #16641: Fix default values of sched.scheduler.enter arguments were
+ modifiable.
+
- Issue #16504: IDLE now catches SyntaxErrors raised by tokenizer. Patch by
Roger Serwy.