node/doc/contributing/backporting-to-release-line...

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# How to backport a pull request to a release line
## Staging branches
Each release line has a staging branch that serves as a workspace for preparing releases.
The branch format is `vN.x-staging`, where `N` is the major release number.
For active staging branches, refer to the [Release Schedule][].
## Identifying changes that require a backport
If a cherry-pick from `main` doesn't apply cleanly on a staging branch, the pull request
will be labeled for the release line (e.g., `backport-requested-vN.x`). This indicates
that manual backporting is required.
## Criteria for backporting
The "Current" release line is more flexible than LTS lines. LTS branches, detailed in the [Release Plan][],
require commits to mature in the Current release for at least two weeks before backporting.
## Labeling backport issues and PRs
Use the following labels, with `N` in `vN.x` denoting the major release number:
| Label | Description |
| ----------------------- | ------------------------------------------------------------------- |
| backport-blocked-vN.x | PRs for `vN.x-staging` blocked by pending backports from other PRs. |
| backport-open-vN.x | Indicates an open backport for the PR. |
| backport-requested-vN.x | PR awaiting manual backport to `vN.x-staging`. |
| backported-to-vN.x | PR successfully backported to `vN.x-staging`. |
| baking-for-lts | PRs awaiting LTS release after maturation in Current. |
| lts-watch-vN.x | PRs possibly included in `vN.x` LTS releases. |
| vN.x | Issues or PRs impacting `vN.x-staging` (or reproducible on vN.x). |
## Submitting a backport pull request
For the following steps, let's assume that you need to backport PR `123`
to the vN.x release line. All commands will use the `vN.x-staging` branch
as the target branch. In order to submit a backport pull request to another
branch, simply replace `N` with the version number for the targeted release
line.
### Automated process
1. Ensure [`@node-core/utils`][] is installed.
2. Execute [`git node backport`][] command:
```bash
# Example: Backport PR 123 to vN.x-staging
git node backport 123 --to=N
```
3. Proceed to step 5 in the Manual section below.
### Manual process
1. Checkout the `vN.x-staging` branch.
2. Verify that the local staging branch is up to date with the remote.
3. Create a new branch based on `vN.x-staging`:
```bash
git fetch upstream vN.x-staging:vN.x-staging -f
git checkout -b backport-123-to-vN.x vN.x-staging
```
4. Cherry-pick the desired commit(s):
```bash
git cherry-pick <commit hash>
```
5. Resolve conflicts using `git add` and `git cherry-pick --continue`.
6. Leave the commit message as is. If you think it should be modified, comment
in the pull request. The `Backport-PR-URL` metadata does need to be added to
the commit, but this will be done later.
7. Verify that `make -j4 test` passes.
8. Push the changes to your fork.
9. Open a pull request:
* Target `vN.x-staging`.
* Title format: `[vN.x backport] <commit title>` (e.g., `[v20.x backport] process: improve performance of nextTick`).
* Reference the original PR in the description.
10. Update the `backport-requested-vN.x` label on the original pull request to `backport-open-vN.x`.
11. If conflicts arise during the review process, the following command be used to rebase:
```bash
git pull --rebase upstream vN.x-staging
```
Once merged, update the original PR's label from `backport-open-vN.x` to `backported-to-vN.x`.
[Release Plan]: https://github.com/nodejs/Release#release-plan
[Release Schedule]: https://github.com/nodejs/Release#release-schedule
[`@node-core/utils`]: https://github.com/nodejs/node-core-utils
[`git node backport`]: https://github.com/nodejs/node-core-utils/blob/main/docs/git-node.md#git-node-backport