neovim/CONTRIBUTING.md

Contributing to Neovim

Getting started

• Help us review open pull requests! See Reviewing for guidelines.
• Try an entry-level issue if you are wondering where to start.
• Or merge a Vim patch.

Reporting problems

• Check the FAQ.
• Search existing issues (including closed!)
• Update Neovim to the latest version to see if your problem persists.
• If you're using a plugin manager, comment out your plugins, then add them back in one by one, to narrow down the cause of the issue.
• Crash reports which include a stacktrace are 10x more valuable.
• Bisecting to the cause of a regression often leads to an immediate fix.

Pull requests ("PRs")

• To avoid duplicate work, you may want to create a [WIP] pull request so that others know what you are working on.
• Avoid cosmetic changes to unrelated files in the same commit: extra noise makes reviews more difficult.
• Use a feature branch instead of the master branch.
• Rebase your feature branch onto (upstream) master before opening the PR.
• After addressing the review comments, it's fine to rebase and force-push to your review.
• Try to tidy your history: combine related commits with interactive rebasing, separate monolithic commits, etc.

Stages: WIP, RFC

Pull requests are processed in two stages: WIP (Work In Progress) and RFC (Request For Comment).

• Untagged PRs are assumed to be RFC, meaning the work is ready for review and you would like feedback.
• Preprend [WIP] to the PR title if you are not ready for feedback and the work is still in flux. This saves time and confusion.

Commit messages

Follow commit message hygiene to make reviews easier and to make the VCS/git logs more valuable.

• Try to keep the first line under 72 characters.
• Prefix the commit subject with a scope: doc:, test:, foo.c:, runtime:, ...
  • For commits that contain only style/lint changes, a single-word subject line is preferred: style or lint.
• A blank line must separate the subject from the description.
• Use the imperative voice: "Fix bug" rather than "Fixed bug" or "Fixes bug."

Automated builds (CI)

Each pull request must pass the automated builds (travis CI and quickbuild).

• CI builds are compiled with -Werror, so if your PR introduces any compiler warnings, the build will fail.
• If any tests fail, the build will fail. See Building Neovim#running-tests to run tests locally. Passing locally doesn't guarantee passing the CI build, because of the different compilers and platforms tested against.
• CI runs ASan and other analyzers. To run valgrind locally: VALGRIND=1 make test
• The lint build (#3174) checks modified lines and their immediate neighbors. This is to encourage incrementally updating the legacy style to meet our style guidelines.
  • A single word (lint or style) is sufficient as the subject line of a commit that contains only style changes.
• How to investigate QuickBuild failures

Coverity

Coverity runs against the master build. If you want to view the defects, just request access at the Contributor level. An Admin will grant you permission.

Use this commit-message format for coverity fixes:

coverity/<id>: <description of what fixed the defect>

where <id> is the Coverity ID (CID). For example see #804.

Reviewing

To help review pull requests, start with this checklist.

Reviewing can be done on GitHub, but you may find it easier to do locally. Using hub, you can create a new branch with the contents of a pull request, e.g. #1820:

hub checkout https://github.com/neovim/neovim/pull/1820

Use git log -p master..FETCH_HEAD to list all commits in the feature branch which aren't in the master branch; -p shows each commit's diff. To show the whole surrounding function of a change as context, use the -W argument as well.