node/COLLABORATOR_GUIDE.md

Node.js Collaborator Guide

Contents

• Issues and Pull Requests
• Accepting Modifications

• Involving the CTC

• Landing Pull Requests

• Technical HOWTO
• I Just Made a Mistake
• Long Term Support

This document contains information for Collaborators of the Node.js project regarding maintaining the code, documentation and issues.

Collaborators should be familiar with the guidelines for new contributors in CONTRIBUTING.md and also understand the project governance model as outlined in GOVERNANCE.md.

Issues and Pull Requests

Courtesy should always be shown to individuals submitting issues and pull requests to the Node.js project.

Collaborators should feel free to take full responsibility for managing issues and pull requests they feel qualified to handle, as long as this is done while being mindful of these guidelines, the opinions of other Collaborators and guidance of the CTC.

Collaborators may close any issue or pull request they believe is not relevant for the future of the Node.js project. Where this is unclear, the issue should be left open for several days to allow for additional discussion. Where this does not yield input from Node.js Collaborators or additional evidence that the issue has relevance, the issue may be closed. Remember that issues can always be re-opened if necessary.

See "Who to CC in issues"

Accepting Modifications

All modifications to the Node.js code and documentation should be performed via GitHub pull requests, including modifications by Collaborators and CTC members.

All pull requests must be reviewed and accepted by a Collaborator with sufficient expertise who is able to take full responsibility for the change. In the case of pull requests proposed by an existing Collaborator, an additional Collaborator is required for sign-off.

In some cases, it may be necessary to summon a qualified Collaborator to a pull request for review by @-mention.

If you are unsure about the modification and are not prepared to take full responsibility for the change, defer to another Collaborator.

Before landing pull requests, sufficient time should be left for input from other Collaborators. Leave at least 48 hours during the week and 72 hours over weekends to account for international time differences and work schedules. Trivial changes (e.g. those which fix minor bugs or improve performance without affecting API or causing other wide-reaching impact) may be landed after a shorter delay.

For non-breaking changes, if there is no disagreement amongst Collaborators, a pull request may be landed given appropriate review. Where there is discussion amongst Collaborators, consensus should be sought if possible. The lack of consensus may indicate the need to elevate discussion to the CTC for resolution (see below).

Breaking changes (that is, pull requests that require an increase in the major version number, known as semver-major changes) must be elevated for review by the CTC. This does not necessarily mean that the PR must be put onto the CTC meeting agenda. If multiple CTC members approve (LGTM) the PR and no Collaborators oppose the PR, it can be landed. Where there is disagreement among CTC members or objections from one or more Collaborators, semver-major pull requests should be put on the CTC meeting agenda.

All bugfixes require a test case which demonstrates the defect. The test should fail before the change, and pass after the change.

All pull requests that modify executable code should be subjected to continuous integration tests on the project CI server.

Involving the CTC

Collaborators may opt to elevate pull requests or issues to the CTC for discussion by assigning the ctc-review label. This should be done where a pull request:

• has a significant impact on the codebase,
• is inherently controversial; or
• has failed to reach consensus amongst the Collaborators who are actively participating in the discussion.

The CTC should serve as the final arbiter where required.

Landing Pull Requests

• Please never use GitHub's green "Merge Pull Request" button.
  • If you do, please force-push removing the merge.
  • Reasons for not using the web interface button:
    • The merge method will add an unnecessary merge commit.
    • The rebase & merge method adds metadata to the commit title.
    • The rebase method changes the author.
    • The squash & merge method has been known to add metadata to the commit title.
    • If more than one author has contributed to the PR, only the latest author will be considered during the squashing.

Always modify the original commit message to include additional meta information regarding the change process:

• A PR-URL: line that references the full GitHub URL of the original pull request being merged so it's easy to trace a commit back to the conversation that led up to that change.
• A Fixes: X line, where X either includes the full GitHub URL for an issue, and/or the hash and commit message if the commit fixes a bug in a previous commit. Multiple Fixes: lines may be added if appropriate.
• A Refs: line referencing a URL for any relevant background.
• A Reviewed-By: Name <email> line for yourself and any other Collaborators who have reviewed the change.
  • Useful for @mentions / contact list if something goes wrong in the PR.
  • Protects against the assumption that GitHub will be around forever.

Review the commit message to ensure that it adheres to the guidelines outlined in the contributing guide.

See the commit log for examples such as this one if unsure exactly how to format your commit messages.

Additionally:

• Double check PRs to make sure the person's full name and email address are correct before merging.
• Except when updating dependencies, all commits should be self contained (meaning every commit should pass all tests). This makes it much easier when bisecting to find a breaking change.

Technical HOWTO

Optional: ensure that you are not in a borked am/rebase state

$ git am --abort
$ git rebase --abort

Checkout proper target branch

$ git checkout master

Update the tree

$ git fetch origin
$ git merge --ff-only origin/master

Apply external patches

$ curl -L https://github.com/nodejs/node/pull/xxx.patch | git am --whitespace=fix

Check and re-review the changes

$ git diff origin/master

Check number of commits and commit messages

$ git log origin/master...master

If there are multiple commits that relate to the same feature or one with a feature and separate with a test for that feature, you'll need to use squash or fixup:

$ git rebase -i origin/master

This will open a screen like this (in the default shell editor):

pick 6928fc1 crypto: add feature A
pick 8120c4c add test for feature A
pick 51759dc feature B
pick 7d6f433 test for feature B

# Rebase f9456a2..7d6f433 onto f9456a2
#
# Commands:
#  p, pick = use commit
#  r, reword = use commit, but edit the commit message
#  e, edit = use commit, but stop for amending
#  s, squash = use commit, but meld into previous commit
#  f, fixup = like "squash", but discard this commit's log message
#  x, exec = run command (the rest of the line) using shell
#
# These lines can be re-ordered; they are executed from top to bottom.
#
# If you remove a line here THAT COMMIT WILL BE LOST.
#
# However, if you remove everything, the rebase will be aborted.
#
# Note that empty commits are commented out

Replace a couple of picks with fixup to squash them into a previous commit:

pick 6928fc1 crypto: add feature A
fixup 8120c4c add test for feature A
pick 51759dc feature B
fixup 7d6f433 test for feature B

Replace pick with reword to change the commit message:

reword 6928fc1 crypto: add feature A
fixup 8120c4c add test for feature A
reword 51759dc feature B
fixup 7d6f433 test for feature B

Save the file and close the editor. You'll be asked to enter a new commit message for that commit. This is a good moment to fix incorrect commit logs, ensure that they are properly formatted, and add Reviewed-By lines.

• The commit message text must conform to the commit message guidelines.

Time to push it:

$ git push origin master

• Optional: Force push the amended commit to the branch you used to open the pull request. If your branch is called bugfix, then the command would be git push --force-with-lease origin master:bugfix. When the pull request is closed, this will cause the pull request to show the purple merged status rather than the red closed status that is usually used for pull requests that weren't merged. Only do this when landing your own contributions.

• Close the pull request with a "Landed in <commit hash>" comment. If your pull request shows the purple merged status then you should still add the "Landed in .." comment if you added multiple commits.

• ./configure && make -j8 test

  • -j8 builds node in parallel with 8 threads. Adjust to the number of cores or processor-level threads your processor has (or slightly more) for best results.

I Just Made a Mistake

• Ping a CTC member.
• #node-dev on freenode
• With git, there's a way to override remote trees by force pushing (git push -f). This should generally be seen as forbidden (since you're rewriting history on a repository other people are working against) but is allowed for simpler slip-ups such as typos in commit messages. However, you are only allowed to force push to any Node.js branch within 10 minutes from your original push. If someone else pushes to the branch or the 10 minute period passes, consider the commit final.
  • Use --force-with-lease to minimize the chance of overwriting someone else's change.
  • Post to #node-dev (IRC) if you force push.

Long Term Support

What is LTS?

Long Term Support (often referred to as LTS) guarantees application developers a 30 month support cycle with specific versions of Node.js.

You can find more information in the full LTS plan.

How does LTS work?

Once a stable branch enters LTS, changes in that branch are limited to bug fixes, security updates, possible npm updates, documentation updates, and certain performance improvements that can be demonstrated to not break existing applications. Semver-minor changes are only permitted if required for bug fixes and then only on a case-by-case basis with LTS WG and possibly Core Technical Committee (CTC) review. Semver-major changes are permitted only if required for security related fixes.

Once a stable branch moves into Maintenance mode, only critical bugs, critical security fixes, and documentation updates will be permitted.

Landing semver-minor commits in LTS

The default policy is to not land semver-minor or higher commits in any LTS branch. However, the LTS WG or CTC can evaluate any individual semver-minor commit and decide whether a special exception ought to be made. It is expected that such exceptions would be evaluated, in part, on the scope and impact of the changes on the code, the risk to ecosystem stability incurred by accepting the change, and the expected benefit that landing the commit will have for the ecosystem.

Any collaborator who feels a semver-minor commit should be landed in an LTS branch should attach the lts-agenda label to the pull request. The LTS WG will discuss the issue and, if necessary, will escalate the issue up to the CTC for further discussion.

How are LTS Branches Managed?

There are currently three LTS branches: v4.x, v0.10, and v0.12. Each of these is paired with a "staging" branch: v4.x-staging, v0.10-staging, and v0.12-staging.

As commits land in master, they are cherry-picked back to each staging branch as appropriate. If the commit applies only to the LTS branch, the PR must be opened against the staging branch. Commits are selectively pulled from the staging branch into the LTS branch only when a release is being prepared and may be pulled into the LTS branch in a different order than they were landed in staging.

Any collaborator may land commits into a staging branch, but only the release team should land commits into the LTS branch while preparing a new LTS release.

How can I help?

When you send your pull request, consider including information about whether your change is breaking. If you think your patch can be backported, please feel free to include that information in the PR thread.

Several LTS related issue and PR labels have been provided:

• lts-watch-v4.x - tells the LTS WG that the issue/PR needs to be considered for landing in the v4.x-staging branch.
• lts-watch-v0.10 - tells the LTS WG that the issue/PR needs to be considered for landing in the v0.10-staging branch.
• lts-watch-v0.12 - tells the LTS WG that the issue/PR needs to be considered for landing in the v0.12-staging branch.
• land-on-v4.x - tells the release team that the commit should be landed in a future v4.x release
• land-on-v0.10 - tells the release team that the commit should be landed in a future v0.10 release
• land-on-v0.12 - tells the release team that the commit should be landed in a future v0.12 release

Any collaborator can attach these labels to any PR/issue. As commits are landed into the staging branches, the lts-watch- label will be removed. Likewise, as commits are landed in a LTS release, the land-on- label will be removed.

Collaborators are encouraged to help the LTS WG by attaching the appropriate lts-watch- label to any PR that may impact an LTS release.

How is an LTS release cut?

When the LTS working group determines that a new LTS release is required, selected commits will be picked from the staging branch to be included in the release. This process of making a release will be a collaboration between the LTS working group and the Release team.