Awkward

Updated Awkward <--> Arrow conversion to preserve nullability in type (PRs 602, 606). Preemptively avoiding warnings from NumPy 1.20 (599) and fixed 32-bit Linux cases in the tests (604).

henryiii fixed hardcoded threads in MacOS compilation target (for deploying to conda-forge).

Fixed 597 with PR 598. Otherwise identical to 1.0.1rc3.

DeprecationWarning -> FutureWarning, add test samples to sdist, and do one last release candidate (1.0.1rc3).

If the source tarball for this (on PyPI) can run all tests, then we're good and I can release 1.0.1. Hopefully, that will happen today.

jrueb implemented the `ak.unflatten` function (583).

jpivarski fixed segfault int `ak.to_numpy(ak.layout.NumpyArray(cupy.array([1, 2, 3]))` (591), changed the definition of RegularArray to accept `size == 0` (590), which was inspired by a corner-case revealed in testing `ak.unflatten`, and that, in turn, required the `ak.to_arrayset`/`ak.from_arrayset` serialization to be overhauled (592). Because any interface changes should be formally deprecated now, these functions must be renamed: `ak.to_buffers`/`ak.from_buffers`; why this had to be changed (with RegularArray examples) is described here: https://github.com/scikit-hep/awkward-1.0/pull/592#issuecomment-743430896

If no one finds any problems with this release candidate, it will be released as 1.0.1 on Monday. All other features will now target 1.0.2rc1. After 1.0.1 is out, the release candidates leading up to it will be deleted from PyPI.

Actually removed the features that were supposed to be removed in 1.0.0 (576).

Fixed the `setup.py --record` argument, needed for `bdist_rpm` (577).

Implemented `ak.Array.ndim` in the Numba context (578).

Updated the internal `broadcast_and_apply` and `recursively_apply` interfaces to support `axis < 0` for some functions (582). Used that to add an `axis` parameter to `ak.is_none` (587). Also fixed a corner-case in `ak.flatten`'s `axis` handling (586).

First version 1.0.0 (non release candidate)! From now on, when users

bash
pip install awkward


(without any version qualification) they will get Awkward 1.x, not Awkward 0.x.

This release also has a few bug-fixes: a memory leak in ArrayBuilder and `ak.combinations` (570) and converting Awkward 0 `Table` with non-trivial `_view` into Awkward 1 `RecordArray`, which would sometimes be wrapped in an `IndexedArray` for the `_view` (573).

This version of Awkward Array is compiled against [pybind11 version 2.6.0](https://github.com/pybind/pybind11/releases/tag/v2.6.0) and [RapidJSON version 1.1.0](https://github.com/Tencent/rapidjson/releases/tag/v1.1.0) (though RapidJSON is not part of the public interface the way pybind11 is: only pybind11 might have to be version-matched, not RapidJSON).