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Patina Rust and Toolchain Version Update Process

TL;DR

  • Cadence: Update at least once per quarter. Do not jump to a new stable release the day it ships.
  • Toolchain are specified in: rust-toolchain.toml (nightly channel) and the rust-version field in each crate's Cargo.toml.
  • Nightly selection: Use the "Branched from master" date for the target stable release from releases.rs.
  • Review: Open the PR against main, add the OpenDevicePartnership/patina-contributors team, and leave it open for at least three full business days.

Rust is released on a regular six week cadence. The Rust project maintains a site with dates for upcoming releases. While there is no hard requirement to update the Rust version used by Patina in a given timeframe, it is recommended to do so at least once per quarter. Updates to the latest stable version should not happen immediately after the stable version release as Patina consumers may need time to update their internal toolchains to migrate to the latest stable version.

A pull request that updates the Rust version should always be created against the main branch. The pull request should include the OpenDevicePartnership/patina-contributors team as reviewers and remain open for at least three full business days to ensure that stakeholders have an opportunity to review and provide feedback.

Updating the Minimum Supported Rust Version

The Rust toolchain used in this repo is specified in rust-toolchain.toml. The minimum supported Rust version for the crates in the workspace is specified in the rust-version field of each crate's Cargo.toml file. When updating the Rust toolchain version, the minimum supported Rust version should be evaluated to determine if it also needs to be updated.

A non-exhaustive list of reasons the minimum version might need to change includes:

  1. An unstable feature has been stabilized and the corresponding #![feature(...)] has been removed
  2. A feature introduced in the release is immediately being used in the repository

Note

If the minimum supported Rust version does need to change, please add a comment explaining why. Note that formatting and linting changes to satisfy tools like rustfmt or clippy do not alone necessitate a minimum Rust version change.

A quick way to check if the minimum supported Rust version needs to change is to keep the changes made for the new release in your workspace and then revert the Rust toolchain to the previous version. If the project fails to build, then the minimum supported Rust version needs to be updated.

Choosing a Nightly Version

Patina currently builds against nightly Rust since the project depends on a small number of unstable features. Unless there is a compelling reason to update the nightly version, it is recommended to continue using the same nightly version until the next stable release. The project typically takes the nightly version listed as the "Branched from master" date for the release on releases.rs. For example, the 1.97.0 release has a "branched from master on" date of "22 May, 2026".

Tip

If you need to find the commit that the stable release was branched from, you can use git to find the commit hash working within the https://github.com/rust-lang/rust repository. For example, git merge-base main 1.95.0 returns 67aec36df76a7b67b71a8ee47684467e16f1847e. git show 67aec36df76a7b67b71a8ee47684467e16f1847e returns:

commit 67aec36df76a7b67b71a8ee47684467e16f1847e
Merge: 3a70d0349fa 70da8044517
Author: bors <bors@rust-lang.org>
Date:   Fri Feb 27 22:04:20 2026 +0000

releases.rs - 1.95.0 also lists the "Branched from master on" date as "27 Feb, 2026".