Hello
I removed some assert calls in distutils some time ago because the
package was not behaving correctly when people were using Python with
the --optimize flag. In other words, assert became a full part of the
code logic and removing them via -O was changing the behavior.
In my opinion assert should be avoided completely anywhere else than
in the tests. If this is a wrong statement, please let me know why :)
So, I grepped the stdlib for assert calls, and I have found 177 of
them and many of them are making Python acts differently depending on
the -O flag,
Here's an example on a randomly picked assert in the threading module:
>>>>>>>>>>>>>>>>>>>>>>>>
import threading
class test(threading.Thread):
def __init__(self):
self.bla = 1
def run(self):
print('running')
t = test()
print(t)
<<<<<<<<<<<<<<<<<<<<<<
The __repr__ method is not behaving the same way depending on the O flag:
$ python3 -O test.py
Traceback (most recent call last):
File "test.py", line 12, in <module>
print(t)
File "/usr/local/lib/python3.2/threading.py", line 652, in __repr__
if self._started.is_set():
AttributeError: 'test' object has no attribute '_started'
$ python3 test.py
Traceback (most recent call last):
File "test.py", line 12, in <module>
print(t)
File "/usr/local/lib/python3.2/threading.py", line 650, in __repr__
assert self._initialized, "Thread.__init__() was not called"
AttributeError: 'test' object has no attribute '_initialized'
$ python test.py
Traceback (most recent call last):
File "test.py", line 12, in <module>
print(t)
File "/usr/lib/python2.6/threading.py", line 451, in __repr__
assert self.__initialized, "Thread.__init__() was not called"
AssertionError: Thread.__init__() was not called
<--- oops different error
$ python -O test.py
Traceback (most recent call last):
File "test.py", line 12, in <module>
print(t)
File "/usr/lib/python2.6/threading.py", line 453, in __repr__
if self.__started.is_set():
AttributeError: 'test' object has no attribute '_Thread__started'
I have seen some other places where thing would simply break with -O.
Am I right thinking we should do a pass on those and remove them or
turn them into exception that are triggered with -O as well ?
This flag is meant to "optimize generated bytecode slightly", but I am
not sure this involves also slightly changing the way the code behaves
Cheers
Tarek
--
Tarek Ziadé | http://ziade.org
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