[yt-dev] Issue #765: ('gas', 'Dark_Matter_Density') fails to load (yt_analysis/yt)

[Nathan Goldbaum]

New issue 765: ('gas', 'Dark_Matter_Density') fails to load
https://bitbucket.org/yt_analysis/yt/issue/765/gas-dark_matter_density-fails-to-load

Nathan Goldbaum:

I ran into this while trying to load all of the fields in `pf.h.field_list`.  The following script illustrates the issue:

```
from yt.mods import *
pf = load("IsolatedGalaxy/galaxy0030/galaxy0030")
print pf.h.field_list[0]
pf.h.all_data()[pf.h.field_list[0]]
```

on the current tip of yt-3.0 (b3e969705199), this outputs:

```
('gas', 'Dark_Matter_Density')
Traceback (most recent call last):
  File "test2.py", line 4, in <module>
    pf.h.all_data()[pf.h.field_list[0]]
  File "/Users/goldbaum/Documents/yt-hg/yt/data_objects/data_containers.py", line 191, in __getitem__
    self.get_data(f)
  File "/Users/goldbaum/Documents/yt-hg/yt/data_objects/data_containers.py", line 582, in get_data
    self._generate_fields(fields_to_generate)
  File "/Users/goldbaum/Documents/yt-hg/yt/data_objects/data_containers.py", line 598, in _generate_fields
    self.field_data[field] = self._generate_field(field)
  File "/Users/goldbaum/Documents/yt-hg/yt/data_objects/data_containers.py", line 221, in _generate_field
    tr = self._generate_fluid_field(field)
  File "/Users/goldbaum/Documents/yt-hg/yt/data_objects/data_containers.py", line 239, in _generate_fluid_field
    rv = self._generate_spatial_fluid(field, ngt_exception.ghost_zones)
  File "/Users/goldbaum/Documents/yt-hg/yt/data_objects/data_containers.py", line 252, in _generate_spatial_fluid
    preload_fields = deps)):
  File "/Users/goldbaum/Documents/yt-hg/yt/data_objects/data_containers.py", line 486, in chunks
    for chunk in self.hierarchy._chunk(self, chunking_style, **kwargs):
  File "/Users/goldbaum/Documents/yt-hg/yt/geometry/grid_geometry_handler.py", line 280, in _chunk_spatial
    for i, og in enumerate(giter):
  File "/Users/goldbaum/Documents/yt-hg/yt/geometry/geometry_handler.py", line 694, in next
    chunk, self.preload_fields) or {}
  File "/Users/goldbaum/Documents/yt-hg/yt/frontends/enzo/io.py", line 175, in _read_chunk_data
    dg = h5py.h5d.open(fid, "/Grid%08i/%s" % (g.id, fname))
  File "h5d.pyx", line 80, in h5py.h5d.open (h5py/h5d.c:1728)
KeyError: 'not found (Dataset: Object not found)'
```

This issue appears to be fixed in the unitrefactor, so it may not be worth worrying about too much.  Something to keep in mind though.