runtime failure seems to trace to astropy 5.0 reorganization

[jrthorstensen]

I'm trying to run a python 3 script calling APLpy from a conda python 3.9 environment on Linux. It fails with:

  File "/home/thorsten/bin/makeNotionCharts.py", line 39, in <module>
    from aplpy import *
  File "/usr/local/anaconda3/envs/py3/lib/python3.9/site-packages/aplpy/__init__.py", line 14, in <module>
    from .core import FITSFigure  # noqa
  File "/usr/local/anaconda3/envs/py3/lib/python3.9/site-packages/aplpy/core.py", line 20, in <module>
    from astropy.nddata.utils import block_reduce
ImportError: cannot import name 'block_reduce' from 'astropy.nddata.utils' (/usr/local/anaconda3/envs/py3/lib/python3.9/site-packages/astropy/nddata/utils.py)

I looked at this and it appears that block_reduce is now in astropy/nddata, not in astropy/nddata/utils:

>>> import astropy
>>> astropy.__version__
'5.0'
>>> 
>>> import astropy.nddata as nd
>>> dir(nd)
['BitFlagNameMap', 'CCDData', 'Conf', 'Cutout2D', 'FlagCollection', 'IncompatibleUncertaintiesException', 'InvalidBitFlag', 'InverseVariance', 'MissingDataAssociationException', 'NDArithmeticMixin', 'NDData', 'NDDataArray', 'NDDataBase', 'NDDataRef', 'NDIOMixin', 'NDSlicingMixin', 'NDUncertainty', 'NoOverlapError', 'PartialOverlapError', 'StdDevUncertainty', 'UnknownUncertainty', 'VarianceUncertainty', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__path__', '__spec__', '_config', 'add_array', 'bitfield_to_boolean_mask', 'bitmask', 'block_reduce', 'block_replicate', 'blocks', 'ccddata', 'compat', 'conf', 'decorators', 'extend_bit_flag_map', 'extract_array', 'fits_ccddata_reader', 'fits_ccddata_writer', 'flag_collection', 'interpret_bit_flags', 'mixins', 'nddata', 'nddata_base', 'nddata_withmixins', 'nduncertainty', 'overlap_slices', 'reshape_as_blocks', 'subpixel_indices', 'support_nddata', 'utils']
>>> dir(nd.utils)
['Cutout2D', 'NoOverlapError', 'PartialOverlapError', 'Sip', 'SkyCoord', '__all__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', 'add_array', 'deepcopy', 'extract_array', 'lazyproperty', 'np', 'overlap_slices', 'proj_plane_pixel_scales', 'skycoord_to_pixel', 'subpixel_indices', 'u']

I suppose I could try to fix my own code by taking out the blanket-import and importing just the part of aplpy I need, which might work, but in the meatime I figured the maintainers would want to know about this. -- John Thorstensen

[jrthorstensen]

Tiny update -- I think everything I'm doing here is with FITSFigure, so I tried changing the import to

from aplpy import FITSFigure

and it fails in the same way.

[jrthorstensen]

Sure enough, I got it running by changing the import line in aplpy's "core.py" from

from astropy.nddata.utils import block_reduce

to

from astropy.nddata import block_reduce

I'm only using FITSFigure, so I haven't run any extensive tests. - John

[dhomeier]

Thanks for reporting this. This is actually the incompatibility fixed in e8c72f0 for the 2.1 release, but the conda channels might need a little more time yet to update to the newest version. In urgent cases you may already install the current release using pip install 'aplpy>=2.1.0'.

[jrthorstensen]

Thanks! I forced the upgrade as you suggested and it now runs without complaining.

[cgobat]

Just an FYI @dhomeier @astrofrog, I just did a brand new install of aplpy via conda-forge today and it seems 2.0.3 is still the latest version available there.

[thatastroguy]

Chiming in here. I just upgraded my astropy to 5.2.2 and ran into this same conflict ImportError: cannot import name 'block_reduce' from 'astropy.nddata.utils' (/Users/ryan/anaconda3/lib/python3.9/site-packages/astropy/nddata/utils.py). Even after ensuring my aplpy version is 2.1.0 (via a forced upgrade), I hit the same error. I'm running Mac OS Monterey v12.4.

I attempted the quick fix provided above by @jrthorstensen above, but I then encounter a different error with a traceback:

---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
Cell In[1], line 10
      8 from astroquery.skyview import SkyView
      9 import matplotlib.pyplot as plt
---> 10 import aplpy
     11 import wget
     12 import urllib.request

File ~/anaconda3/lib/python3.9/site-packages/aplpy/__init__.py:14
     10 # ----------------------------------------------------------------------------
     12 if not _ASTROPY_SETUP_:  # noqa
---> 14     from .core import FITSFigure  # noqa
     15     from .rgb import make_rgb_image, make_rgb_cube  # noqa
     17     from .frame import Frame  # noqa

File ~/anaconda3/lib/python3.9/site-packages/aplpy/core.py:30
     27 from . import slicer
     29 from .compat import simple_norm
---> 30 from .layers import Layers
     31 from .grid import Grid
     32 from .ticks import Ticks

File ~/anaconda3/lib/python3.9/site-packages/aplpy/layers.py:9
      5 from matplotlib.contour import ContourSet
      6 from matplotlib.collections import RegularPolyCollection, \
      7     PatchCollection, CircleCollection, LineCollection
----> 9 from .regions import ArtistCollection
     10 from .decorators import auto_refresh
     13 class Layers(object):

File ~/anaconda3/lib/python3.9/site-packages/aplpy/regions.py:6
      3 from astropy import log
      4 from astropy import wcs
----> 6 from .decorators import auto_refresh
      9 class Regions(object):
     10     """
     11     Regions sub-class of APLpy.
     12 
   (...)
     41 
     42     """

File ~/anaconda3/lib/python3.9/site-packages/aplpy/decorators.py:5
      1 from __future__ import absolute_import, print_function, division
      3 import threading
----> 5 from astropy.utils.decorators import wraps
      7 mydata = threading.local()
      9 __all__ = ['auto_refresh', 'fixdocstring']

ImportError: cannot import name 'wraps' from 'astropy.utils.decorators' (/Users/ryan/anaconda3/lib/python3.9/site-packages/astropy/utils/decorators.py)

Other than trying to roll back my astropy installation, I'm not quite sure what to do. Correction: the solution outlined by bencooper1 in open issue #474 solved this additional issue. Aplpy can now be imported.

[dhomeier]

Both these issues have been fixed in 2.1.0 (#469 and #471); you could install the latest release through pip, but I am also only getting 2.0.3 from mambaforge. @astrofrog do you have an idea how to poke conda/condaforge to pull the current version?

[thatastroguy]

Thanks for the response, @dhomeier. I ran into these issues even after installing 2.1.0 through pip, which is why I was rather confused about running into these errors.

[dhomeier]

You mean you have an installation that reports aplpy.version.version == '2.1.0' and are still getting those errors?

[thatastroguy]

So I had thought. I attempted pip install 'aplpy>=2.1.0', and once I checked the version number using conda list, it appeared that I had the correct version number (2.1.0). But loading a python session, importing aplpy, and checking aplpy.version.version returned 2.0.3 just a moment ago. Using pip install --force-reinstall aplpy has now brought it up to the correct version number: aplpy.version.version=='2.1.0'.

I appreciate the help and I apologize for my confusion!

[dhomeier]

Thanks for the feedback; pip installs on top of conda can create confusion over what is already installed, so it is indeed regrettable condaforge has still not been able to update its package!

[thriveth]

Thanks, I have faced the same problem and fixed it installing via pip. I really wish the Conda folks would bump the version in the repositories so it would be, like, not broken.

[cgobat]

The merging of conda-forge/aplpy-feedstock#10 earlier this morning has now made APLpy v2.1.0 available through conda-forge. It seems that should likely resolve all of the issues discussed here.