JaggedArray.pad fails when content is empty

[benkrikler]

Jagged array's pad method has troubles when the array contents is empty (even if starts or stops is not). This is the case with the latest release at least, so version 0.12.9

To recreate:

from awkward import JaggedArray
vals = [[], []]
a = JaggedArray.fromiter(vals)
print(a.pad(1, clip=True))

output:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "~/.conda/envs/fast-carpenter/lib/python2.7/site-packages/awkward/array/jagged.py", line 1861, in pad
    content = self._content[index]
IndexError: index -1 is out of bounds for axis 0 with size 0

Same is true if clip=False or if vals=[[]]

[jpivarski]

Thanks for pointing this out!

Recently, the majority of bugs can be labeled, "Numpy corner cases," like this one. That's one of the main motivations for the C++ version: implementations of methods like pad will be more straightforward (internally as for loops) where this kind of gaffe would more likely be noticed.

[jpivarski]

This will be awkward 0.12.10.