2026 Feature Update 4

[mdekstrand]

Fourth feature update release in 2026! Mostly smaller features, but some useful ones.

See the release notes at https://lenskit.org/stable/releases/2026.html for highlights.

What's Changed

• Improve test coverage and coverage measurement by @mdekstrand in Improve test coverage and coverage measurement #1185
• Add power measurement to doctor by @mdekstrand in Add power measurement to doctor #1189
• Make pipeline schemas strict by @mdekstrand in Make pipeline schemas strict #1193
• Add GitHub Actions group markers to CLI test output by @mdekstrand in Add GitHub Actions group markers to CLI test output #1195
• Add AMBAR music dataset to Lenskit by @sushobhan2024 in Add AMBAR music dataset to Lenskit #1187
• Make power doctor robust to empty returns by @mdekstrand in Make power doctor robust to empty returns #1197
• Export JSON schemas into the documentation site by @mdekstrand in Export JSON schemas into the documentation site #1194
• Warn about a missing history component only when one could be missing by @appleweiping in Warn about a missing history component only when one could be missing #1209
• add query-time pooling for flexMF by @samiravaez in add query-time pooling for flexMF #1201
• Convert numeric interaction timestamps by @appleweiping in Convert numeric interaction timestamps #1210
• Add CUDA tests to the test matrix by @mdekstrand in Add CUDA tests to the test matrix #1188
• Add pre-commit/prek file again, update Ruff, and fix lints by @mdekstrand in Add pre-commit/prek file again, update Ruff, and fix lints #1216
• Correct ItemList.top_n to generate new ranks by @mdekstrand in Correct ItemList.top_n to generate new ranks #1221
• Refactor CLI tests without Perl by @mdekstrand in Refactor CLI tests without Perl #1219
• Rework build scripts to use shell + Just instead of Mise by @mdekstrand in Rework build scripts to use shell + Just instead of Mise #1220
• Remove remaining mise definitions + doc references by @mdekstrand in Remove remaining mise definitions + doc references #1223
• Exclude rank from fields when loading Arrow tables by @mdekstrand in Exclude rank from fields when loading Arrow tables #1226
• Update dependencies by @mdekstrand in Update dependencies #1225

New Contributors

• @appleweiping made their first contribution in Warn about a missing history component only when one could be missing #1209

Full Changelog: v2026.3.0...v2026.4.0

---

This discussion was created from the release 2026 Feature Update 4.