Version 2.13.0

Numba compatibility

numba 0.67.0 and llvmlite 0.49.0, both released on 2026-08-11, rewrote numba.core.cgutils.pointer_add, which broke Awkward Array's Numba integration: indexing an ak.Array inside a jitted function fails to compile with RuntimeError: LLVM IR parsing error (invalid cast opcode for cast from 'i64' to 'ptr'). Awkward Array 2.12.0 and earlier are affected, on every platform and Python version.

This release restores it (#4298). Users staying on an older Awkward Array can pin numba<0.67.

What's Changed

New features

• feat: fused centered sum-of-squares kernel for ak.var/ak.std at the innermost axis (CPU + CUDA) by @ianna in #4256
• feat: add the experimental-API mark (functions, methods, properties) by @TaiSakuma in #4279

Bug Fixes

• fix: flatten(axis=None) dropped data or raised on nested unions by @TaiSakuma in #4246
• fix: linear fit overflow by @ianna in #4257
• fix: nested zero-field RecordArray length in virtual from_buffers by @TaiSakuma in #4293
• fix: empty result for ak.ravel/ak.flatten(axis=None) with nothing to merge by @TaiSakuma in #4292
• fix: pass pointers, not raw addresses, to numba's cgutils.pointer_add by @ariostas in #4298

Documentation

• docs: add summary lines to 11 to_* array-library converter docstrings by @TaiSakuma in #4138
• docs: add summary lines to 13 to_* file/format converter docstrings by @TaiSakuma in #4139
• docs: note tests/properties naming in CONTRIBUTING.md by @TaiSakuma in #4273

Testing

• test: add no-raise property tests for ak.flatten and ak.all by @TaiSakuma in #4265
• test: add known-issue predicates for #4278 and #4280 to property tests by @TaiSakuma in #4281
• test: add known-issue predicates for #4255 and #4274 to property tests by @TaiSakuma in #4275
• test: add a no-raise property-test module for ak.ravel by @TaiSakuma in #4284

Build & CI

• chore: use scikit-build-core 1.0 for awkward-cpp by @henryiii in #4236
• chore: drop the over-broad files override on the zizmor hook by @TaiSakuma in #4266
• chore(deps): bump hypothesis-awkward from 0.19.0 to 0.19.1 by @dependabot[bot] in #4271
• chore(deps): bump the actions group with 5 updates by @dependabot[bot] in #4272
• chore: split generated release notes into finer categories by @TaiSakuma in #4267
• ci: limit thread pools in the coverage job by @henryiii in #4276
• ci: set the Dependabot cooldown to zero for hypothesis-awkward by @TaiSakuma in #4290
• chore: remove inert from __future__ import annotations imports by @TaiSakuma in #4296
• chore(deps): bump the actions group with 3 updates by @dependabot[bot] in #4295

Full Changelog: v2.12.0...v2.13.0