[IronPython] very strange dictionnary bug

[Stanislas Pinte]

Dino Viehland a écrit :
> Could something like this be happening?
> 
> x = {2:3, 4:5}
> for a in x.keys():
>     if a == 2:
>         del x[2]
>         x[3] = 'abc'
>     assert x.has_key(a)

Both CPython and IPython raise an AssertionError with that snippet. And
they should, IMHO. I don't think it is simimar to the following, because
the has_key(...) call must reflect the current state of the keys.

> 
> 
> This is similar to:
> 
> x = {2:3, 4:5}
> keys = x.keys()
> del x[4]
> x[7] = 23
> for a in keys:
>  print a
> 
> where both CPython and IronPython print 2 and 4 (there is a snapshot of keys saved after the call to x.keys() and any modifications that don't alter the size of the dictionary aren't caught).
> 
> 
> IronPython prints
> ________________________________________
> From: users-bounces at lists.ironpython.com On Behalf Of Stanislas Pinte
> Sent: Friday, August 18, 2006 8:26 AM
> To: Discussion of IronPython
> Subject: Re: [IronPython] very strange dictionnary bug
> 
> Dino Viehland a écrit :
>> I haven't seen anything like this before... But I have a couple of questions:  Are the keys always strings when it repros?  And is the dictionary always created using the {} syntax?
> 
> the keys are always strings, and the dict is instantiated only once,
> with the {} syntax.
> 
> Thanks,
> 
> Stan.
>> I ask because we have a lot of different dictionary implementations, or there could be a bug where we have different instances of some basic object that are hashing differently for some reason (although given the code below, that seems strange).
>>
>> -----Original Message-----
>> From: users-bounces at lists.ironpython.com [mailto:users-bounces at lists.ironpython.com] On Behalf Of Stanislas Pinte
>> Sent: Friday, August 18, 2006 7:38 AM
>> To: Discussion of IronPython
>> Subject: Re: [IronPython] very strange dictionnary bug
>>
>> By the way, the environment in which the bug shows up is single-threaded, so I do not suspect any concurrent access problem.
>>
>> Stan.
>>
>> Stanislas Pinte a écrit :
>>> Hello,
>>>
>>> We are just seeing a very strange bug in the following code:
>>>
>>> myDictionnary = {}
>>> .
>>> for key in myDictionnary.keys():
>>>   assert myDictionnary.has_key(key) --> throw AssertionError
>>>
>>> this is fixed by the following change:
>>>
>>> for key, value in myDictionnary.iteritems():
>>>   ...
>>>
>>> Ever seen this?
>>>
>>> Too bad I cannot reproduce this...a very simple test case like the one
>>> below doesn't do the trick...
>>>
>>> thanks,
>>>
>>> Stan.
>>>
>>> [sim-ironpython]> ironpython/ipy.exe
>>> IronPython 1.0.60816 on .NET 2.0.50727.42 Copyright (c) Microsoft
>>> Corporation. All rights reserved.
>>>>>> a = {"one": 1, "two": 2, "three": 3} a["one"]
>>> 1
>>>>>> a.pop("one")
>>> 1
>>>>>> a
>>> {'two': 2, 'three': 3}
>>>>>> a.keys()
>>> ['two', 'three']
>>>>>> for k in a.keys():
>>> .     print k
>>> .
>>> two
>>> three
>>>
>>
>> --
>> -----------------------------------------------------------------
>>    Stanislas Pinte             e-mail: stan at ertmssolutions.com
>>    ERTMS Solutions               http://www.ertmssolutions.com
>>    Rue de l'Autonomie, 1             Tel:    + 322 - 522.06.63
>>    1070        Bruxelles              Fax:   + 322 - 522.09.30
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>>
> 
> 
> --
> -----------------------------------------------------------------
>    Stanislas Pinte             e-mail: stan at ertmssolutions.com
>    ERTMS Solutions               http://www.ertmssolutions.com
>    Rue de l'Autonomie, 1             Tel:    + 322 - 522.06.63
>    1070        Bruxelles              Fax:   + 322 - 522.09.30
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-- 
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   Stanislas Pinte             e-mail: stan at ertmssolutions.com
   ERTMS Solutions               http://www.ertmssolutions.com
   Rue de l'Autonomie, 1             Tel:    + 322 - 522.06.63
   1070        Bruxelles              Fax:   + 322 - 522.09.30
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   Skype (http://www.skype.com) id:                  stanpinte
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