Skip to content
Cargo

once_cell

Single assignment cells and lazy values.

About
lazy-evaluationrust
github.com/matklad/once_cellMITAlex Kladov27.5M / week2.1k · 126 forks · 59 contributors
Compare
Compares against 1.21.4 (latest stable)
Latest Stable1.21.4Mar 12, 2026
Latest RC1.16.0-pre.1Oct 22, 2022
Release cadenceEvery month
Last releaseMar 12, 2026
Open advisories0
Changelog quality80% curated
CHANGELOG, gaps for some releases
Release history SecurityYou're on
1.x
STABLE · RCPRE-RELEASEAprJulOct2024AprJulOct2025AprJulOct2026

55 older or filtered releases not shown.

Upgrade guides

Breaking changes and a migration checklist for each major version
once_cell 0.2 → 10.2.4 → 1.21.4Mar 12, 2026 BreakingBreaking6Security1Platform7Deprecated1New22Changed11Fixed12Other10once_cell 0.1 → 0.20.1.8 → 0.2.4Jul 21, 2019 BreakingBreaking1Platform1New5Changed4Fixed1Other1once_cell 0.0 → 0.10.0.3 → 0.1.8Feb 7, 2019 BreakingPlatform1New2Changed2Other1
VersionChannelDateChangesSecurity
1.21.4 StableMar 12, 2026Fixed11.21.3 StableMar 28, 2025Other11.21.2 StableMar 27, 2025Other11.21.1 StableMar 13, 2025Platform11.21.0 StableMar 10, 2025Platform1New2Other11.20.3 youStableFeb 6, 2025No notes published1.20.2 StableOct 5, 2024Breaking11.20.1 StableSep 29, 2024New11.20.0 YankedSep 13, 2024No notes published1.19.0 StableDec 7, 2023Other11.18.0 StableJun 4, 2023Platform11.17.2 StableMay 29, 2023Fixed11.17.1 StableFeb 14, 2023Fixed11.17.0 StableDec 29, 2022New11.16.0 StableOct 29, 2022Deprecated1New11.16.0-pre.1 RCOct 22, 2022No notes published1.15.0 StableSep 20, 2022Platform1Fixed11.15.0-pre.1 RCSep 15, 2022No notes published1.14.0 StableSep 2, 2022New11.13.1 StableAug 16, 2022Changed2