docs(dev-guide): update release-process.md to match the new workflow based on GitHub Merge Queue

doc/dev-guide/src/release-process.md

@@ -3,33 +3,65 @@
 Before making a release, ensure that `rustup-init.sh` is behaving correctly,
 and that you're satisfied that nothing in the ecosystem is breaking because
 of the update. A useful set of things to check includes verifying that
-real-world toolchains install okay, and that `rls-vscode` isn't broken by
+real-world toolchains install okay, and that `rust-analyzer` isn't broken by
 the release. While it's not our responsibility if they depend on non-stable
 APIs, we should behave well if we can.
 
+As a maintainer, you have two options to choose from when cutting a new
+release: a beta release or an official release.
+The main difference between the two is that they use different values for
+the `RUSTUP_UPDATE_ROOT` environment variable:
+- A beta release is deployed on `https://dev-static.rust-lang.org/rustup`.
+- An official release is deployed on `https://static.rust-lang.org/rustup`.
+
+By switching between those two values, Rustup effectively provides two "self
+update channels", making beta testing possible with `rustup self update`.
+
 Producing the final release artifacts is a bit involved because of the way
-Rustup is distributed. The steps for a release are:
+Rustup is distributed.
+Below is a list of things to be done in order to cut a new [b]eta release
+or an official [r]elease:
 
-1. Update `Cargo.toml` and `download/Cargo.toml`to have the same new version
-   (optionally make a commit)
-2. Run `cargo build` and review `Cargo.lock` changes
-   if all looks well, make a commit
-3. Update `rustup-init.sh` version to match the commit
-   details for `Cargo.lock`
-4. Push this to the `stable` branch (git push origin HEAD:stable)
-5. While you wait for green CI, double-check the `rustup-init.sh` functionality
-   and `rustup-init` just in case.
-6. Ensure all of CI is green on the `stable` branch.
+1. [b/r] In a separate PR:
+   1. If the version strings in `Cargo.toml`s haven't been updated:
+      - Decide what the new version number `$VER_NUM` should be.
+        > **Note:** We always increment the *minor* number unless:
+        > - A major incompatibility has been introduced in this release:
+        >   increment the *major* number instead.
+        > - This release is a hotfix because the last one had a defect:
+        >   increment the *patch* number instead.
+      - Update `Cargo.toml` and `download/Cargo.toml` to have that same new
+        version number, then run `cargo build` and review `Cargo.lock` changes.
+      If all looks well, make a commit.
+   2. Update `CHANGELOG.md` accordingly if necessary.
+2. [b/r] After merging the PR made in step 1, in a separate PR:
+   1. Update the commit shasum in `rustup-init.sh` to match the latest commit
+      on `master`.
+3. [b/r] After merging the PR made in step 2, sync `master` to `stable` using
+   `--ff-only`:
+   - `git fetch origin master:master`
+   - `git checkout stable && git merge --ff-only master`
+   - `git push origin HEAD:stable`
+4. [b/r] While you wait for green CI on `stable`, double-check the
+   functionality of `rustup-init.sh` and `rustup-init` just in case.
+5. [b/r] Ensure all of CI is green on the `stable` branch.
    Once it is, check through a representative proportion of the builds looking
-   for the reported version statements to ensure that we definitely built something
-   cleanly which reports as the right version number when run `--version`.
-7. Ping someone in the release team to perform the actual release.
-   They can find instructions in `ci/sync-dist.py`
-   Note: Some manual testing occurs here, so hopefully they'll catch
-   anything egregious in which case abort the change and roll back.
-8. Once the official release has happened, prepare and push a tag
-   of that commit, and also push the content to master
-   - `git tag -as $VER_NUM -m $VER_NUM` (optionally without -s if not GPG
+   for the reported version statements to ensure that
+   we definitely built something cleanly which reports as the right version
+   number when run `--version`.
+6. [r] Make a new PR to the [Rust Blog] adding a new release announcement post.
+7. [b/r] Ping someone in the release team to perform the actual release.
+   They can find instructions in `ci/sync-dist.py`.
+   > **Note:** Some manual testing occurs here, so hopefully they'll catch
+     anything egregious in which case abort the change and roll back.
+8. [b] Once the beta release has happened, post a new topic named "Seeking beta
+   testers for Rustup $VER_NUM" on the [Internals Forum].
+9. [r] Once the official release has happened, prepare and push a tag on the
+   latest `stable` commit.
+   - `git tag -as $VER_NUM -m $VER_NUM` (optionally without `-s` if not GPG
      signing the tag)
    - `git push origin HEAD:master`
    - `git push origin $VER_NUM`
+
+[Rust Blog]: https://github.com/rust-lang/blog.rust-lang.org
+[Internals Forum]: https://internals.rust-lang.org