Reviewing Pull Requests

As a community we believe in the value of code reviews for all contributions. Code reviews increase both the quality and readability of our code base, which in turn produces high quality software.

This document provides guidelines for how we review issues and merge pull requests (PRs).

• Pull requests welcome
• Code reviewers
• Reviewing changes
  • Holds
• Maintainers
• Merging PRs

Pull requests welcome

First and foremost: as a potential contributor, your changes and ideas are welcome at any hour of the day or night, weekdays, weekends, and holidays. Please do not ever hesitate to ask a question or send a PR.

Code reviewers

The code review process can introduce latency for contributors and additional work for reviewers that can frustrate both parties. Consequently, as a community we expect that all active participants in the community will also be active reviewers. We ask that active contributors to the project participate in the code review process in areas where that contributor has expertise.

Reviewing changes

Once a PR has been submitted, reviewers should attempt to do an initial review to do a quick "triage" (e.g. close duplicates, identify user errors, etc.), and potentially identify which maintainers should be the focal points for the review.

If a PR is closed, without accepting the changes, reviewers are expected to provide sufficient feedback to the originator to explain why it is being closed.

During a review, PR authors are expected to respond to comments and questions made within the PR - updating the proposed change as appropriate.

After a review of the proposed changes, reviewers may either approve or reject the PR. To approve they should add a LGTM comment to the PR. To reject they should add a NOT LGTM comment along with a full justification for why they are not in favor of the change. If a PR gets a NOT LGTM vote then this issue should be discussed among the group to try to resolve their differences.

Because reviewers are often the first points of contact between new members of the community and can therefore significantly impact the first impression of the Istio community, reviewers are especially important in shaping the community. Reviewers are highly encouraged to review the code of conduct and are strongly encouraged to go above and beyond the code of conduct to promote a collaborative and respectful community.

Reviewers are expected to respond in a timely fashion to PRs that are assigned to them. Reviewers are expected to respond to active PRs with reasonable latency, and if reviewers fail to respond, those PRs may be assigned to other reviewers. Active PRs are considered those which have a proper CLA (cla:yes) label and do not need rebase to be merged. PRs that do not have a proper CLA, or require a rebase are not considered active PRs.

Holds

Any member who wants to review a PR but does not have time immediately may put a hold on a PR simply by saying so on the PR discussion and offering an ETA measured in single-digit days at most. Any PR that has a hold shall not be merged until the person who requested the hold acks the review, withdraws their hold, or is overruled by a preponderance of maintainers.

Maintainers

Merging of PRs is executed by robots which are triggered by maintainer peer review.

Like many open source projects, becoming a maintainer is based on contributions to the project. Please see our community roles document for information on how this is done.

Merging PRs

PRs may only be merged after the following criteria are met:

1. It has no NO LGTM comment from a reviewer.
2. It has been LGTM-ed by at least one of the maintainers of that repository.
3. It has all appropriate corresponding documentation and tests.