Column name prevents use of Table.where()

[ljleppan]

Using "where" as a column name gives no indication of anything being wrong while creating/filling table, but produces an ValueError when filtering by said column.

Code to demonstrate issue:

from tables import *

class Thing(IsDescription):
    where = StringCol(1)
    where_ = StringCol(1)

h5file = open_file('test.h5', mode='w', title='Test file')
group = h5file.create_group('/', 'test', 'Test')
table = h5file.create_table(group, 'readout', Thing, 'Test')

print("{!r}".format(h5file))

table.row['where'] = "A"
table.row['where_'] = "B"
table.row.append()
table.flush()

table = h5file.root.test.readout

for result in table.where("where_ == b'B'"):
    print(result['where'], result['where_'], "\n") # As expected

for result in table.where("where == b'A'"): # Raises ValueError
    print(result['where'], result['where_']) 

Output:

$ python test.py 
File(filename=test.h5, title='Test file', mode='w', root_uep='/', filters=Filters(complevel=0, shuffle=False, bitshuffle=False, fletcher32=False, least_significant_digit=None))
/ (RootGroup) 'Test file'
/test (Group) 'Test'
/test/readout (Table(0,)) 'Test'
  description := {
  "where": StringCol(itemsize=1, shape=(), dflt=b'', pos=0),
  "where_": StringCol(itemsize=1, shape=(), dflt=b'', pos=1)}
  byteorder := 'little'
  chunkshape := (32768,)

b'A' b'B' 

Traceback (most recent call last):
  File "test.py", line 23, in <module>
    for result in table.where("where == b'A'"):
  File "/home/ljleppan/venv/lib/python3.5/site-packages/tables/table.py", line 1483, in where
    return self._where(condition, condvars, start, stop, step)
  File "/home/ljleppan/venv/lib/python3.5/site-packages/tables/table.py", line 1501, in _where
    compiled = self._compile_condition(condition, condvars)
  File "/home/ljleppan/venv/lib/python3.5/site-packages/tables/table.py", line 1361, in _compile_condition
    "in condition ``%s``" % (condition,))
ValueError: there are no columns taking part in condition ``where == b'A'``
Closing remaining open files:test.h5...done

Python version: 3.5.2
PyTables version: 3.4.2

It's understandable if this is a "wontfix" in terms of allowing the column name, but even then I'd hope for a slightly more informative error message.