There’s a steady trickle of patches that need to be ported to the beta branch. Only a few people are even aware of the process, but this is actually something anybody can do.
When somebody identifies a PR that should be backported to beta they
means they want one of the teams to evaluate whether the patch should
be backported. I also suggest applying the
I-nominated and and a
T- (team) tag as appropriate: that’ll really get their
attention. Anybody with triage access is free to make these
tags. Backports are mostly done to fix regressions. If the team thinks
it should be backported they’ll then additionally tag it
At that point the PR is ready to be backported. So the list of patches
ready for a backport is those tagged both
So now somebody needs to go through those PR’s and cherry-pick their
commits to the beta branch. Those cherry-picks are then submitted as a
PR against the beta branch, with a title started with
reviewers can see its specialness). The OP of that PR should contain
links to all the PRs being backported. Here’s an
example. Anybody can
make these PRs!
After that a reviewer needs to verify that the backport looks correct,
that it’s submitted to the beta branch, and then approve via
Finally, they need to follow the links to the original PRs and remove the
beta-nominated tag (people forget to do this a lot). This last step indicates
that the backport has been completed, so the
beta-accepted tags have three states.
The procedure for backporting fixes to Cargo is similar bug slightly more
extended than the
rust-lang/rust repo’s procedure. Currently there aren’t
backport tags in the Cargo repository, but you’ll initiate the backport process
by commenting on an associated PR, requesting a backport. Once a Cargo team
member has approved the backport to happen you’re good to start sending PRs!
First you’ll send a PR to the
rust-1.21.0branch of Cargo (replace 1.21 with the current rustc beta version number). Like with
rust-lang/rustyou’ll prefix the title of your PR with
[beta]and ensure it’s flagged as going to beta.
Next a Cargo reviewer will
@bors: r+the PR and put it into the queue. Eventually bors will automatically merge the PR (when tests are passing) to the appropriate Cargo branch.
Finally you’ll send a PR to the
betabranch, updating the Cargo submodule. The Cargo submodule should be updated to the tip of the
rust-1.21.0branch (the branch your Cargo PR was merged to). As like before, ensure you’ve got
[beta]in the PR title.
After that’s all said and done the Cargo change is ready to get scheduled onto the beta release!