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<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>CPython does the exact same thing:<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>Python 2.6.3 (r263rc1:75186, Oct 2 2009, 20:40:30)
[MSC v.1500 32 bit (Intel)] on win32<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>Type "help", "copyright",
"credits" or "license" for more information.<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>>>> class my_exc(Exception):<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>... def __init__(self, message,
param):<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>...
super(my_exc, self).__init__(message)<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>...
self.param = param<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>...<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>>>><o:p> </o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>>>> e = my_exc('message','param')<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>>>> import pickle<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>>>> pickle.loads(pickle.dumps(e))<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>Traceback (most recent call last):<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'> File "<stdin>", line 1, in
<module><o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'> File "C:\Python26\lib\pickle.py", line
1374, in loads<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'> return Unpickler(file).load()<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'> File "C:\Python26\lib\pickle.py", line
858, in load<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'> dispatch[key](self)<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'> File "C:\Python26\lib\pickle.py", line
1133, in load_reduce<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'> value = func(*args)<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>TypeError: __init__() takes exactly 3 arguments (2 given)<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>>>><o:p> </o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>You can override __<i>reduce</i>_ex__ so that it’ll
match up with your __init__ method:<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>class my_exc(Exception):<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'> def __init__(self, message, param):<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>
super(my_exc, self).__init__(message)<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>
self.param = param<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'> def __reduce_ex__(self, protocol):<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>
return (my_exc, (self.message, self.param))<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>e = my_exc('message','param')<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>import pickle<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>pickle.loads(pickle.dumps(e))<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'>It looks like you should be able to just override
__reduce__ but it looks like IronPython calls __reduce_ex__ where CPython calls
__reduce__ for some reason. I’ve filed that as bug 25731 <a
href="http://ironpython.codeplex.com/WorkItem/View.aspx?WorkItemId=25731">http://ironpython.codeplex.com/WorkItem/View.aspx?WorkItemId=25731</a><o:p></o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span
style='color:#1F497D'><o:p> </o:p></span></p>
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<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> users-bounces@lists.ironpython.com
[mailto:users-bounces@lists.ironpython.com] <b>On Behalf Of </b>Idan Zaltzberg<br>
<b>Sent:</b> Sunday, December 20, 2009 2:57 AM<br>
<b>To:</b> users@lists.ironpython.com<br>
<b>Subject:</b> [IronPython] Bug in Ipy 2.6 when pickling exceptions<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><o:p> </o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>Hi,<o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>I'm
using IronPython 2.6 final. <o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>When
deriving from Exception class, and creating a constructor with a different
signature (not 1 argument), I get an exception when pickling and unpickling.<o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>Seems
like the pickling process "neglects" some of the information so the
unpickling fails.<o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>This
can be reproduced with:<o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'> <o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>>>>
class my_exc(Exception):<o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>...
def __init__(self, message, param):<o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>...
super(my_exc, self).__init__(message)<o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>...
self.param = param<o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>...<o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>>>>
e = my_exc('message','param')<o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>>>>
import pickle<o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>>>>
pickle.loads(pickle.dumps(e))<o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>Traceback
(most recent call last):<o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>
File "<stdin>", line 1, in <module><o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>
File "C:\Systems\3rd_party\IronPython\2.6\Lib\pickle.py", line 1374,
in loads<o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>
File "C:\Systems\3rd_party\IronPython\2.6\Lib\pickle.py", line 858,
in load<o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>
File "C:\Systems\3rd_party\IronPython\2.6\Lib\pickle.py", line 1133,
in load_reduce<o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>TypeError:
__init__() takes exactly 3 arguments (2 given)<o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'> <o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'> <o:p></o:p></p>
<p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>Thanks.<o:p></o:p></p>
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