The Rust Release Process

Here’s how Rust is currently released:

Bump the stable version number (T-6 days, Friday the week before)

Open a PR bumping the version number in src/version. r+ rollup=never this PR.

Mark it as rollup=never, because if it lands in a rollup as not the first PR then other pull requests in that rollup will be incorrectly associated with the prior release.

This is effectively when the beta branch forks – when beta is promoted, it will be based off of the PR that landed just before this version number bump PR.

Promote branches (T-3 days, Monday)

Both promotions should happen on Monday. You can open both PRs at the same time, but make sure the stable promotion lands first.

Beta to stable

Obtain AWS CLI credentials and run this command from the simpleinfra repository:

./release-scripts/ branches

Once that’s done, send a PR to the freshly created beta branch of rust-lang/rust with two commits:

  • The changes caused by running ./ run replace-version-placeholder
  • An update of src/ci/channel to beta

The version placeholder replacement changes must be in a separate commit so that they can be cherry picked to the master branch.

Also send a PR to rust-lang/rust targeting the new stable branch making the following changes:

  • Update src/ci/channel to stable
  • Update release notes to the latest available copy
    • e.g., git checkout origin/master --

Once the PRs are sent, r+ both and give them a high p=1000 (for stable) and p=10 for beta.

After the PR is merged you’ll need to start a dev release. Obtain AWS CLI credentials and run this command from the simpleinfra repository:

# The date here is of the actual, production, stable release. Used for the blog post.
./release-scripts/ release dev stable --release-date YYYY-MM-DD

Master bootstrap update (T-2 day, Tuesday)

Send a PR to the master branch to:

  • Cherry pick the commit that ran ./ run replace-version-placeholder from the now merged beta branch PR. Do not re-run the tool as there might have been other stabilizations on master which were not included in the branched beta, so may not be attributed to the current release.

  • Run ./ run src/tools/bump-stage0 to update the bootstrap compiler to the beta you created yesterday.

  • Remove references to the bootstrap and not(bootstrap) conditional compilation attributes. You can find all of them by installing ripgrep and running this command:

    rg '#!?\[.*\(bootstrap' -t rust

    The general guidelines (both for #[] and #![]) are:

    • Remove any item annotated with #[cfg(bootstrap)].
    • Remove any #[cfg(not(bootstrap))] attribute while keeping the item.
    • Remove any #[cfg_attr(bootstrap, $attr)] attribute while keeping the item.
    • Replace any #[cfg_attr(not(bootstrap), doc="$doc")] with $doc in the relevant documentation block (or in a new documentation block).
    • Replace any #[cfg_attr(not(bootstrap), $attr)] with #[$attr].

Release day (Thursday)

Decide on a time to do the release, T.

  • T-50m - Run the following command in a shell with AWS credentials in the simpleinfra repository:

    ./release-scripts/ release prod stable

    That’ll, in the background, schedule the promote-release binary to run on the production secrets (not the dev secrets). That’ll sign everything, upload it, update the html index pages, and invalidate the CDN. Note that this takes about 30 minutes right now. This will also push a signed tag to rust-lang/rust.

  • T-2m - Merge blog post.

  • T - Tweet and post everything!

  • T+5m - Release and tag Cargo. From a rust-lang/rust checkout (script will checkout the stable branch automatically), run the following script from simpleinfra.

  • T+1hr Send a PR to the beta branch running ./ run src/tools/bump-stage0 to bump the boostrap compiler to the stable you just released.

Bask in your success.

Rebuilding stable pre-releases

If something goes wrong and we need to rebuild the stable artifacts, merge the PR on the stable branch of the rust-lang/rust repository. Once the commit is merged, issue the following command in a shell with AWS credentials on the simpleinfra repository:

./release-scripts/ release dev stable --bypass-startup-checks

You’ll also want to update the previously published blog post and internals post with the new information.

Publishing a nightly based off a try build

Sometimes a PR requires testing how it behaves when downloaded from rustup, for example after a manifest change. In those cases it’s possible to publish a new nightly based off that PR on

Once the try build finishes grab the merge commit SHA and run the following command in a shell with AWS credentials on the simpleinfra repository:

./release-scripts/ release dev nightly $MERGE_COMMIT_SHA

When the release process end you’ll be able to install the new nightly with:

RUSTUP_DIST_SERVER= rustup toolchain install nightly