fix: always check '.length' for 'unknown_length'

[jpivarski]

@pfackeldey, is this correct? Here are the matches, post-fix.

% fgrep -r '.length == ' src/
src/awkward/contents/bitmaskedarray.py:        if self._mask.length is not unknown_length and self._mask.length == 0:
src/awkward/contents/bitmaskedarray.py:        if self._mask.length is not unknown_length and self._mask.length == 0:
src/awkward/contents/bitmaskedarray.py:            if self._mask.length is not unknown_length and self._mask.length == excess_length:
src/awkward/contents/listarray.py:        if offsets.length is not unknown_length and offsets.length == 0:
src/awkward/contents/listarray.py:                advanced.length is not unknown_length and advanced.length == 0
src/awkward/contents/listarray.py:                advanced.length is not unknown_length and advanced.length == 0
src/awkward/contents/listarray.py:        if self._starts.length is not unknown_length and self._starts.length == 0:
src/awkward/contents/listarray.py:        if self._starts.length is not unknown_length and self._starts.length == 0:
src/awkward/contents/unmaskedarray.py:            if offsets.length is not unknown_length and offsets.length == 0:
src/awkward/contents/unmaskedarray.py:        if self._content.length is not unknown_length and self._content.length == 0:
src/awkward/contents/unmaskedarray.py:        if self._content.length is not unknown_length and self._content.length == 0:
src/awkward/contents/numpyarray.py:        if self.length is not unknown_length and self.length == 0:
src/awkward/contents/numpyarray.py:                return out.content.length is not unknown_length and out.content.length == self.length
src/awkward/contents/numpyarray.py:                return out.length is not unknown_length and out.length == self.length
src/awkward/contents/content.py:            if out.length is not unknown_length and out.length == 0:
src/awkward/contents/content.py:            if out.length is not unknown_length and out.length == 0:
src/awkward/contents/content.py:                or self.length == other.length
src/awkward/contents/indexedarray.py:        if self._index.length is not unknown_length and self._index.length == 0:
src/awkward/contents/indexedarray.py:        if self._index.length is not unknown_length and self._index.length == 0:
src/awkward/contents/indexedarray.py:            if self._content.length is not unknown_length and self._content.length == 0:
src/awkward/contents/indexedarray.py:                # every masked value is self._content[0], unless self._content.length == 0.
src/awkward/contents/indexedarray.py:        if self._content.length is not unknown_length and self._content.length == 0:
src/awkward/contents/indexedarray.py:            # every masked value is self._content[0], unless self._content.length == 0.
src/awkward/contents/indexedarray.py:        if not nplike.known_data or self._index.length == 0:
src/awkward/contents/unionarray.py:        if simplified.length is not unknown_length and simplified.length == 0:
src/awkward/contents/unionarray.py:        if self.length is not unknown_length and self.length == 0:
src/awkward/contents/unionarray.py:        if simplified.length is not unknown_length and simplified.length == 0:
src/awkward/contents/listoffsetarray.py:            and offsets.length == 0
src/awkward/contents/listoffsetarray.py:        if offsets.length is not unknown_length and offsets.length == 0:
src/awkward/contents/listoffsetarray.py:        if offsets.length is not unknown_length and offsets.length == 0:
src/awkward/contents/listoffsetarray.py:                advanced.length is not unknown_length and advanced.length == 0
src/awkward/contents/listoffsetarray.py:                advanced.length is not unknown_length and advanced.length == 0
src/awkward/contents/listoffsetarray.py:            if inneroffsets.length is not unknown_length and inneroffsets.length == 0:
src/awkward/contents/listoffsetarray.py:                self._offsets.length is not unknown_length and self._offsets.length == 1
src/awkward/contents/listoffsetarray.py:                return out2.length == self.length
src/awkward/contents/listoffsetarray.py:            if self.starts.length is not unknown_length and self.starts.length == 0:
src/awkward/contents/indexedoptionarray.py:        if self._content.length is not unknown_length and self._content.length == 0:
src/awkward/contents/indexedoptionarray.py:            if offsets.length is not unknown_length and offsets.length == 0:
src/awkward/contents/indexedoptionarray.py:        if self._index.length is not unknown_length and self._index.length == 0:
src/awkward/contents/indexedoptionarray.py:        if not nplike.known_data or self._index.length == 0:
src/awkward/contents/bytemaskedarray.py:            if offsets.length is not unknown_length and offsets.length == 0:
src/awkward/contents/bytemaskedarray.py:        if self._mask.length is not unknown_length and self._mask.length == 0:
src/awkward/contents/bytemaskedarray.py:        if self._mask.length is not unknown_length and self._mask.length == 0:
src/awkward/contents/emptyarray.py:        if not carry.nplike.known_data or carry.length == 0:
src/awkward/contents/emptyarray.py:            if not head.nplike.known_data or head.length == 0:
src/awkward/contents/regulararray.py:        if offsets.length is not unknown_length and offsets.length == 0:
src/awkward/contents/regulararray.py:                advanced.length is not unknown_length and advanced.length == 0
src/awkward/contents/regulararray.py:                advanced.length is not unknown_length and advanced.length == 0
src/awkward/contents/regulararray.py:                        or trimmed.length == self._size * outcontent.length
src/awkward/contents/recordarray.py:            or out.length == self._length
src/awkward/contents/recordarray.py:            (x if x.length == length else x[:length])._to_arrow(
src/awkward/_broadcasting.py:        if x.length is not unknown_length and x.length == 0:
src/awkward/_broadcasting.py:        if x.length is not unknown_length and x.length == 0:
src/awkward/record.py:        if self._array.length is not unknown_length and self._array.length == 1:
src/awkward/operations/ak_enforce_type.py:        if layout_regular.length is not unknown_length and layout_regular.length == 0:
src/awkward/operations/ak_firsts.py:        if layout.length is not unknown_length and layout.length == 0:

[pfackeldey]

These changes look reasonable to me 👍
I'm just confused why the JAX tests are failing for {ubuntu,macOS} with python 3.{10,11,12} ? This seems to be unrelated to this PR though...

[jpivarski]

It's hard to diagnose because of the JAX PyTrees control flow, but at least one of the errors was caused by this change:

awkward/src/awkward/contents/bytemaskedarray.py

Line 687 in b2d48e9

if offsets.length is not unknown_length and offsets.length == 0:

(from ak.unflatten). The pattern-match solution apparently doesn't work and we'll have to think carefully about each case. I'll make this a draft.

But this may be an indication that we need to rethink the JAX backend, too. (I'm still worried about that...)

[pfackeldey]

I tend to agree. Despite being a JAX fan, I think it is more important that awkward-array with typetracer backend works flawlessly.

[agoose77]

Yeah, unfortunately this kind of logic is not easy to pattern match. When I was reworking this handling, I started to make an effort to standardise unknown length handling, but I definitely think there's a long tail on this. Over time, though, we'll get them all :)