862909ee4f
Using codespell, went over the docs and fixed some typos. Refs: https://github.com/scylladb/scylladb/issues/16255 Signed-off-by: Yaniv Kaul <yaniv.kaul@scylladb.com> Closes scylladb/scylladb#16275
95 lines
4.1 KiB
Markdown
95 lines
4.1 KiB
Markdown
# Backport
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Backport queue is implemented using github issues and github label.
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1. All patches that fix things must come with a Fixes: #nnnn line; if a
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patchset it should be present on the cover letter as well. All patches
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with Fixes: should also include which branches need backport (perhaps
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none) by including Branches: w.x, y.z or Branches: none
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2. Maintainers will insist on rule 1
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3. After a patch with a Fixes #nnnn line gets promoted, a bot wakes up
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and assigns the label [Backport candidate] to that issue iff:
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- no Branches: was added
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- Branches: w.x was added
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In case the "Branches: none" was specified the label [Backport
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candidate] is not set
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4. Once a week or so a maintainer wakes up and filters the issue list of
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open [Backport candidate]s.
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5. The maintainer may take the following actions:
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5.1. Decide no branches need the fix, and remove the label
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5.2. Decide the fix does not merit a backport, and remove the label
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(explaining why in the issue)
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5.3. Backport to branches that require it, and remove the label
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5.4. Backport to some branches, but not others, noting which and keeping
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the label
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5.5. Decide that more time is needed to gain confidence in the fix, and
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keep the label
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5.6. Ask someone else (from QA, or the patch author, or anyone relevant)
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for assistance in selecting among the options
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## Contributor instructions
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When backporting the maintainer will try to cherry-pick the changes onto the branch with older version of Scylla,
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but sometimes additional changes are needed to make the change work with old code.
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In such case the maintainer can ask the contributor to prepare a change to work with this particular version.
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Here are the instructions for a contributor on how to properly prepare these changes.
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It's the easiest to show it by an example, so let's look at PR [#12031](https://github.com/scylladb/scylladb/pull/12031), which fixed issue [#12014](https://github.com/scylladb/scylladb/issues/12014).
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### Wait for the original change to get merged
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First the original PR should get merged.
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In the example the author wanted to merge the branch `cvybhu:filter_multi_bug` into `scylladb:master`.
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Each PR is submitted on its own branch, which the PR author wants to merge into the `master` branch.
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Before the changes end up on `master`, they are first added to the `next` branch to run some additional tests. Later the `next` branch is merged into `master` and the PR is officially merged.
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### A backport PR
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Released versions of `Scylla` live on their own branches - `branch-5.0`, `branch-4.6` etc.
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To backport the change we will have to put it on its own branch and merge it into the branch with the desired version.
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In the example, the PR with the backport [#12086](https://github.com/scylladb/scylladb/pull/12086) wants to merge `cvybhu:filter_multi_bug_5.0` into `scylladb:branch-5.0`.
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Before the changes end up on `branch-5.0`, they are first added to the `next-5.0` branch to run some additional tests. Later the `next-5.0` branch is merged into `branch-5.0` and the PR is officially backported.
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### Preparing the backport PR
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1. Go to the branch with the target backport version
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```bash
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git fetch origin branch-5.0
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git checkout -t origin/branch-5.0
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git submodule sync
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git pull origin branch-5.0
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git submodule update --recursive
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```
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2. Create a branch with the fix
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```bash
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git checkout -b my_fix_branch_5.0
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```
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3. Copy the changes to the branch, use the merge commit from `master`.
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This command will copy all commits to the branch at once, which might result in a lot conflicts to resolve. It's also possible to cherry-pick the commits individually in order to tackle the conflicts one at a time. Please use the `-x` option on cherry-pick so that's it's possible to tell where the commit came from.
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```bash
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git cherry-pick -m1 -x 2d2034ea28b8615a130146ad9780010d29d2fcc9
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```
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Resolve conflicts as necessary
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4. Build and run the tests using `dbuild`
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```bash
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./tools/toolchain/dbuild ./configure.py --disable-dpdk
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./tools/toolchain/dbuild ninja dev-test
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```
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4. Push the branch
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```bash
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git push <my-scylla-fork> my_fix_branch_5.0
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```
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5. Open the PR.
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Change the branch so that the merge target is the backport branch (e.g `branch-5.0`) instead of `master`
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