tabulate fails on empty data with `headers` and `colalign`

It’s possible to pass an empty tabular_data value to tabulate along with headers and this works as expected:

>>> import tabulate
>>> print(tabulate.tabulate([], headers=['foo', 'bar']))
foo    bar
-----  -----
>>> 

However, if colalign values are provided as well, it causes an exception:

>>> print(tabulate.tabulate([], headers=['foo', 'bar'], colalign=('left', 'right')))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/ssd/debian-next/venv/lib/python3.8/site-packages/tabulate.py", line 1494, in tabulate
    aligns[idx] = align
IndexError: list assignment index out of range
>>> 

My expectation is that this would behave as if colalign wasn’t passed since there’s no data to align. I encountered this using tabulate 0.8.7.

[Fifty-Nine]

Regarding @Fifty-Nine’s problem, it is fixed in #221 using directlyheadersalign:

Thanks for implementing this! I’ll try it out when I get a chance.

[eliegoudout]

@alexwlchan answered to @AlexanderStein already. Regarding @Fifty-Nine’s problem, it is fixed in #221 using directlyheadersalign:

>>> print(tabulate.tabulate([], headers=['foo', 'bar'], headersalign=('left', 'right')))
foo      bar
-----  -----