247 lines
12 KiB
Markdown
247 lines
12 KiB
Markdown
# Pull request reviewing process
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## Labels
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Labels are carefully picked to optimize for:
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- Readability: maintainers must immediately know the state of a PR
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- Filtering simplicity: different labels represent many different aspects of
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the reviewing work, and can even be targeted at different maintainers groups.
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A pull request should only be attributed labels documented in this section: other labels that may
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exist on the repository should apply to issues.
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### DCO labels
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* `dco/no`: automatically set by a bot when one of the commits lacks proper signature
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### Status labels
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* `status/0-triage`
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* `status/1-design-review`
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* `status/2-code-review`
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* `status/3-docs-review`
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* `status/4-merge`
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Special status labels:
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* `status/failing-ci`: indicates that the PR in its current state fails the test suite
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* `status/needs-attention`: calls for a collective discussion during a review session
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### Impact labels (apply to merged pull requests)
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* `impact/api`
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* `impact/changelog`
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* `impact/cli`
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* `impact/deprecation`
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* `impact/distribution`
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* `impact/dockerfile`
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### Process labels (apply to merged pull requests)
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Process labels are to assist in preparing (patch) releases. These labels should only be used for pull requests.
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Label | Use for
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------------------------------- | -------------------------------------------------------------------------
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`process/cherry-pick` | PRs that should be cherry-picked in the bump/release branch. These pull-requests must also be assigned to a milestone.
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`process/cherry-picked` | PRs that have been cherry-picked. This label is helpful to find PR's that have been added to release-candidates, and to update the change log
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`process/docs-cherry-pick` | PRs that should be cherry-picked in the docs branch. Only apply this label for changes that apply to the *current* release, and generic documentation fixes, such as Markdown and spelling fixes.
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`process/docs-cherry-picked` | PRs that have been cherry-picked in the docs branch
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`process/merge-to-master` | PRs that are opened directly on the bump/release branch, but also need to be merged back to "master"
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`process/merged-to-master` | PRs that have been merged back to "master"
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## Workflow
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An opened pull request can be in 1 of 5 distinct states, for each of which there is a corresponding
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label that needs to be applied.
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### Triage - `status/0-triage`
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Maintainers are expected to triage new incoming pull requests by removing the `status/0-triage`
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label and adding the correct labels (e.g. `status/1-design-review`) before any other interaction
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with the PR. The starting label may potentially skip some steps depending on the kind of pull
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request: use your best judgement.
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Maintainers should perform an initial, high-level, overview of the pull request before moving it to
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the next appropriate stage:
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- Has DCO
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- Contains sufficient justification (e.g., usecases) for the proposed change
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- References the GitHub issue it fixes (if any) in the commit or the first GitHub comment
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Possible transitions from this state:
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* Close: e.g., unresponsive contributor without DCO
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* `status/1-design-review`: general case
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* `status/2-code-review`: e.g. trivial bugfix
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* `status/3-docs-review`: non-proposal documentation-only change
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### Design review - `status/1-design-review`
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Maintainers are expected to comment on the design of the pull request. Review of documentation is
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expected only in the context of design validation, not for stylistic changes.
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Ideally, documentation should reflect the expected behavior of the code. No code review should
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take place in this step.
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There are no strict rules on the way a design is validated: we usually aim for a consensus,
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although a single maintainer approval is often sufficient for obviously reasonable changes. In
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general, strong disagreement expressed by any of the maintainers should not be taken lightly.
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Once design is approved, a maintainer should make sure to remove this label and add the next one.
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Possible transitions from this state:
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* Close: design rejected
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* `status/2-code-review`: general case
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* `status/3-docs-review`: proposals with only documentation changes
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### Code review - `status/2-code-review`
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Maintainers are expected to review the code and ensure that it is good quality and in accordance
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with the documentation in the PR.
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New testcases are expected to be added. Ideally, those testcases should fail when the new code is
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absent, and pass when present. The testcases should strive to test as many variants, code paths, as
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possible to ensure maximum coverage.
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Changes to code must be reviewed and approved (LGTM'd) by a minimum of two code maintainers. When
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the author of a PR is a maintainer, he still needs the approval of two other maintainers.
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Once code is approved according to the rules of the subsystem, a maintainer should make sure to
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remove this label and add the next one. If documentation is absent but expected, maintainers should
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ask for documentation and move to status `status/3-docs-review` for docs maintainer to follow.
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Possible transitions from this state:
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* Close
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* `status/1-design-review`: new design concerns are raised
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* `status/3-docs-review`: general case
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* `status/4-ready-to-merge`: change not impacting documentation
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### Docs review - `status/3-docs-review`
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Maintainers are expected to review the documentation in its bigger context, ensuring consistency,
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completeness, validity, and breadth of coverage across all existing and new documentation.
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They should ask for any editorial change that makes the documentation more consistent and easier to
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understand.
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The docker/docker repository only contains _reference documentation_, all
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"narrative" documentation is kept in a [unified documentation
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repository](https://github.com/docker/docker.github.io). Reviewers must
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therefore verify which parts of the documentation need to be updated. Any
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contribution that may require changing the narrative should get the
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`impact/documentation` label: this is the signal for documentation maintainers
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that a change will likely need to happen on the unified documentation
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repository. When in doubt, it’s better to add the label and leave it to
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documentation maintainers to decide whether it’s ok to skip. In all cases,
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leave a comment to explain what documentation changes you think might be needed.
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- If the pull request does not impact the documentation at all, the docs review
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step is skipped, and the pull request is ready to merge.
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- If the changes in
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the pull request require changes to the reference documentation (either
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command-line reference, or API reference), those changes must be included as
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part of the pull request and will be reviewed now. Keep in mind that the
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narrative documentation may contain output examples of commands, so may need
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to be updated as well, in which case the `impact/documentation` label must
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be applied.
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- If the PR has the `impact/documentation` label, merging is delayed until a
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documentation maintainer acknowledges that a corresponding documentation PR
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(or issue) is opened on the documentation repository. Once a documentation
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maintainer acknowledges the change, she/he will move the PR to `status/4-merge`
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for a code maintainer to push the green button.
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Changes and additions to docs must be reviewed and approved (LGTM'd) by a minimum of two docs
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sub-project maintainers. If the docs change originates with a docs maintainer, only one additional
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LGTM is required (since we assume a docs maintainer approves of their own PR).
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Once documentation is approved, a maintainer should make sure to remove this label and
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add the next one.
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Possible transitions from this state:
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* Close
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* `status/1-design-review`: new design concerns are raised
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* `status/2-code-review`: requires more code changes
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* `status/4-ready-to-merge`: general case
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### Merge - `status/4-ready-to-merge`
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Maintainers are expected to merge this pull request as soon as possible. They can ask for a rebase
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or carry the pull request themselves.
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Possible transitions from this state:
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* Merge: general case
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* Close: carry PR
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After merging a pull request, the maintainer should consider applying one or multiple impact labels
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to ease future classification:
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* `impact/api` signifies the patch impacted the Engine API
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* `impact/changelog` signifies the change is significant enough to make it in the changelog
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* `impact/cli` signifies the patch impacted a CLI command
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* `impact/dockerfile` signifies the patch impacted the Dockerfile syntax
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* `impact/deprecation` signifies the patch participates in deprecating an existing feature
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### Close
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If a pull request is closed it is expected that sufficient justification will be provided. In
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particular, if there are alternative ways of achieving the same net result then those needs to be
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spelled out. If the pull request is trying to solve a use case that is not one that we (as a
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community) want to support then a justification for why should be provided.
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The number of maintainers it takes to decide and close a PR is deliberately left unspecified. We
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assume that the group of maintainers is bound by mutual trust and respect, and that opposition from
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any single maintainer should be taken into consideration. Similarly, we expect maintainers to
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justify their reasoning and to accept debating.
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## Escalation process
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Despite the previously described reviewing process, some PR might not show any progress for various
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reasons:
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- No strong opinion for or against the proposed patch
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- Debates about the proper way to solve the problem at hand
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- Lack of consensus
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- ...
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All these will eventually lead to stalled PR, where no apparent progress is made across several
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weeks, or even months.
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Maintainers should use their best judgement and apply the `status/needs-attention` label. It must
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be used sparingly, as each PR with such label will be discussed by a group of maintainers during a
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review session. The goal of that session is to agree on one of the following outcomes for the PR:
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* Close, explaining the rationale for not pursuing further
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* Continue, either by pushing the PR further in the workflow, or by deciding to carry the patch
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(ideally, a maintainer should be immediately assigned to make sure that the PR keeps continued
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attention)
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* Escalate to Solomon by formulating a few specific questions on which his answers will allow
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maintainers to decide.
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## Milestones
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Typically, every merged pull request get shipped naturally with the next release cut from the
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`master` branch (either the next minor or major version, as indicated by the
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[`VERSION`](https://github.com/docker/docker/blob/master/VERSION) file at the root of the
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repository). However, the time-based nature of the release process provides no guarantee that a
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given pull request will get merged in time. In other words, all open pull requests are implicitly
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considered part of the next minor or major release milestone, and this won't be materialized on
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GitHub.
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A merged pull request must be attached to the milestone corresponding to the release in which it
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will be shipped: this is both useful for tracking, and to help the release manager with the
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changelog generation.
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An open pull request may exceptionally get attached to a milestone to express a particular intent to
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get it merged in time for that release. This may for example be the case for an important feature to
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be included in a minor release, or a critical bugfix to be included in a patch release.
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Finally, and as documented by the [`PATCH-RELEASES.md`](PATCH-RELEASES.md) process, the existence of
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a milestone is not a guarantee that a release will happen, as some milestones will be created purely
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for the purpose of bookkeeping
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