Layout Record should have an 'axis_wrap_if_negative' method

[jpivarski]

Version of Awkward Array

HEAD

Description and code to reproduce

Otherwise, any method that takes an axis fails like this:

AttributeError: 'Record' object has no attribute 'axis_wrap_if_negative'

This affects both v1 and v2. It's a bug, so it should be fixed in both, but v2 is higher priority if there's only time to fix one of them. The fix in v2 can be in Python; the fix in v1 has to be C++ code.

Fields of a record don't count as an axis, so the implementation would be to just pass it to self._array.axis_wrap_if_negative.

However, if the axis that this function returns is equal to 0, that should be an error. The user is trying to compute something on a top-level array, but the top-level is a scalar, not an array. We don't want to pass that through self._array.axis_wrap_if_negative and have, for instance, ak.to_regular(record, axis=0) return an array, especially if that ignores the Record's _at attribute and returns an output containing what had been hidden data.

[agoose77]

Huh, I thought we had an issue tracking this, but apparently not!

[jpivarski]

I don't remember it. I just did a search and didn't find it. If it rings a bell, that's a good sign for consistency, at least.