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astropy.constants doesn't import in python3.3 - #603

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astrofrog:fix-constants-python3.3
Jan 11, 2013
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astropy.constants doesn't import in python3.3#603
astrofrog merged 1 commit into
astropy:masterfrom
astrofrog:fix-constants-python3.3

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@astrofrog

@astrofrog astrofrog commented Jan 11, 2013

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In the 0.2b1 release, astropy.constants doesn't import in python 3.3,
although they do in python 3.2. This was also the case for pre-beta
versions of 0.2.

/sw/lib/python3.3/site-packages/astropy/constants/cgs.py in <module>()
     19 for nm, val in sorted(_cgs.__dict__.items()):
     20     if isinstance(val, ConstantDefinition):
---> 21         _c = Constant(val.value, val.units, val.uncertainty, val.name, val.reference)
     22         locals()[nm] = _c
     23 

/sw/lib/python3.3/site-packages/astropy/constants/constant.py in __new__(cls, value, uncertainty, name, reference, units)
     31 
     32     def __new__(cls, value, uncertainty, name, reference, units):
---> 33         return super(Constant, cls).__new__(cls, value)
     34 
     35     def __repr__(self):

TypeError: object.__new__() takes no parameters

In python3.2, this works correctly.

This problem affects importing pretty much all of the other sub-packages, many of
which do a

from .core import *

resulting in

from ..constants import cgs

This is the current fink version of python33 (3.3.0-3), if that is any help.

@astrofrog astrofrog mentioned this pull request Jan 5, 2013
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@embray

embray commented Jan 10, 2013

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Ah, this just just be super(Constant, cls).__new__(cls); this is subtle but in Python...2.7 I think (?) the object type was changed to not accept any arguments in its constructor. But I guess in Python 3.3 they made that strictly the case. So at the top level of any super call chain in either __new__ or __init__ should be one that doesn't pass on any arguments.

In this case, althought Constant's superclass is actually Quantity, Quantity doesn't implement a custom __new__, so super() resolves straight to object.__new__ and doesn't throw away the arguments passed in on the way.

@embray

embray commented Jan 11, 2013

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In fact, apparently that __new__ is an artifact from what is now the ConstantDefinition class. It can just be removed. It serves no purpose.

@astrofrog

astrofrog commented Jan 11, 2013

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Oh yes, right - I just did that, so once Travis passes I'll merge.

@embray

embray commented Jan 11, 2013

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Is Travis b0rked or something? It doesn't seem to have even put this PR on its queue.

@astrofrog

astrofrog commented Jan 11, 2013

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Yeah, it's in the queue, but no nodes are being fired up. However, given that this is a relatively simple change, I'm just going to go ahead and merge. If there are any issues, Jenkins will pick them up.

astrofrog added a commit that referenced this pull request Jan 11, 2013
@astrofrog
Merge pull request #603 from astrofrog/fix-constants-python3.3
3b855c3 
astropy.constants doesn't import in python3.3
@astrofrog
astrofrog merged commit 3b855c3 into astropy:master Jan 11, 2013
@embray

embray commented Jan 11, 2013

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+1

astrofrog added a commit that referenced this pull request Jan 25, 2013
@astrofrog @embray
Merge pull request #603 from astrofrog/fix-constants-python3.3
6c004bd 
astropy.constants doesn't import in python3.3
embray added a commit that referenced this pull request Feb 13, 2013
@embray
This fixes the Constant class in Python 3.3. This is sort of a replay…
a6e554b 
… of #603 in that, because Quantity does not define a __new__ method super().__new__ in Constant.__new__ resolves directly to object.__new__() which is now strict in taking no arguments (would have caught this sooner using 'python -Wd').  This fix is fine because Constant.__init__ also bypasses Quantity.__init__ so there's no need to pass any of the __init__ arguments to the super()'s __new__ call.
embray added a commit that referenced this pull request Feb 13, 2013
@embray
This fixes the Constant class in Python 3.3. This is sort of a replay…
9820832 
… of #603 in that, because Quantity does not define a __new__ method super().__new__ in Constant.__new__ resolves directly to object.__new__() which is now strict in taking no arguments (would have caught this sooner using 'python -Wd').  This fix is fine because Constant.__init__ also bypasses Quantity.__init__ so there's no need to pass any of the __init__ arguments to the super()'s __new__ call.
keflavich pushed a commit to keflavich/astropy that referenced this pull request Oct 9, 2013
@astrofrog @embray
Merge pull request astropy#603 from astrofrog/fix-constants-python3.3
5283140 
astropy.constants doesn't import in python3.3
keflavich pushed a commit to keflavich/astropy that referenced this pull request Oct 9, 2013
@embray
This fixes the Constant class in Python 3.3. This is sort of a replay…
4ded78b 
… of astropy#603 in that, because Quantity does not define a __new__ method super().__new__ in Constant.__new__ resolves directly to object.__new__() which is now strict in taking no arguments (would have caught this sooner using 'python -Wd').  This fix is fine because Constant.__init__ also bypasses Quantity.__init__ so there's no need to pass any of the __init__ arguments to the super()'s __new__ call.
@astrofrog
astrofrog deleted the fix-constants-python3.3 branch July 5, 2016 18:46
jeffjennings pushed a commit to jeffjennings/astropy that referenced this pull request Jul 2, 2025
@pllim
Merge pull request astropy#603 from eteq/remove-my-maint
5226779 
Remove me from coordinates and utils maintainer role
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@astrofrog @embray