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How to contribute

We'd love to accept your patches and contributions to this project. There are a just a few small guidelines you need to follow.

Contributor License Agreement

Contributions to any Google project must be accompanied by a Contributor License Agreement. This is not a copyright assignment, it simply gives Google permission to use and redistribute your contributions as part of the project. Head over to https://cla.developers.google.com/ to see your current agreements on file or to sign a new one.

You generally only need to submit a CLA once, so if you've already submitted one (even if it was for a different project), you probably don't need to do it again.

Reporting issues

Bugs, feature requests, and development-related questions should be directed to our GitHub issue tracker. If reporting a bug, please try and provide as much context as possible such as your operating system, Go version, and anything else that might be relevant to the bug. For feature requests, please explain what you're trying to do, and how the requested feature would help you do that.

Security related bugs can either be reported in the issue tracker, or if they are more sensitive, emailed to opensource@google.com.

Submitting a patch

  1. It's generally best to start by opening a new issue describing the bug or feature you're intending to fix. Even if you think it's relatively minor, it's helpful to know what people are working on. Mention in the initial issue that you are planning to work on that bug or feature so that it can be assigned to you.

  2. Follow the normal process of forking the project, and set up a new branch to work in. It's important that each group of changes be done in separate branches in order to ensure that a pull request only includes the commits related to that bug or feature.

  3. Any significant changes should almost always be accompanied by tests. The project already has good test coverage, so look at some of the existing tests if you're unsure how to go about it. Coverage is monitored by codecov.io, which flags pull requests that decrease test coverage. This doesn't necessarily mean that PRs with decreased coverage won't be merged. Sometimes a decrease in coverage makes sense, but if your PR is flagged, you should either add tests to cover those lines or add a PR comment explaining the untested lines.

  4. Run script/fmt.sh, script/test.sh and script/lint.sh to format your code and check that it passes all tests and linters. script/lint.sh may also tell you that generated files need to be updated. If so, run script/generate.sh to update them.

  5. Do your best to have well-formed commit messages for each change. This provides consistency throughout the project, and ensures that commit messages are able to be formatted properly by various git tools.

  6. Finally, push the commits to your fork and submit a pull request. NOTE: Please do not use force-push on PRs in this repo, as it makes it more difficult for reviewers to see what has changed since the last code review. We always perform "squash and merge" actions on PRs in this repo, so it doesn't matter how many commits your PR has, as they will end up being a single commit after merging. This is done to make a much cleaner git log history and helps to find regressions in the code using existing tools such as git bisect.

Code Comments

Every exported method needs to have code comments that follow Go Doc Comments. A typical method's comments will look like this:

// Get fetches a repository.
//
// GitHub API docs: https://docs.github.com/rest/repos/repos#get-a-repository
//
//meta:operation GET /repos/{owner}/{repo}
func (s *RepositoriesService) Get(ctx context.Context, owner, repo string) (*Repository, *Response, error) {
u := fmt.Sprintf("repos/%v/%v", owner, repo)
req, err := s.client.NewRequest("GET", u, nil)
...
}

The first line is the name of the method followed by a short description. This could also be a longer description if needed, but there is no need to repeat any details that are documented in GitHub's documentation because users are expected to follow the documentation links to learn more.

After the description comes a link to the GitHub API documentation. This is added or fixed automatically when you run script/generate.sh, so you won't need to set this yourself.

Finally, the //meta:operation comment is a directive to the code generator that maps the method to the corresponding OpenAPI operation. Once again, there can be multiple directives for methods that call multiple endpoints. script/generate.sh will normalize these directives for you, so if you are adding a new method you can use the pattern from the u := fmt.Sprintf line instead of looking up what the url parameters are called in the OpenAPI description.

Metadata

GitHub publishes OpenAPI descriptions of their API. We use these descriptions to keep documentation links up to date and to keep track of which methods call which endpoints via the //meta:operation comments described above. GitHub's descriptions are far too large to keep in this repository or to pull down every time we generate code, so we keep only the metadata we need in openapi_operations.yaml.

openapi_operations.yaml

Most contributors won't need to interact with openapi_operations.yaml, but it may be useful to know what it is. Its sections are:

  • openapi_operations - is the metadata that comes from GitHub's OpenAPI descriptions. It is generated by script/metadata.sh update-openapi and should not be edited by hand. In the rare case where it needs to be overridden, use the operation_overrides section instead.

    An operation consists of name, documentation_url, and openapi_files. openapi_files is the list of files where the operation is described. In order or preference, values can be "api.git.luolix.top.json" for operations available on the free plan, "ghec.json" for operations available on GitHub Enterprise Cloud or "ghes-.json" for operations available on GitHub Enterprise Server. When an operation is described in multiple ghes files, only the most recent version is included. documentation_url is the URL that should be linked from godoc. It is the documentation link found in the first file listed in openapi_files.

  • openapi_commit - is the git commit that script/metadata.sh update-openapi saw when it last updated openapi_operations. It is not necessarily the most recent commit seen because update-openapi doesn't update the file when there are no changes to openapi_operations.

  • operations - contains manually added metadata that is not in GitHub's OpenAPI descriptions. There are only a few of these. Some have documentation_urls that point to relevant GitHub documentation that is not in the OpenAPI descriptions. Others have no documentation_url and result in a note in the generated code that the documentation is missing.

  • operation_overrides - is where we override the documentation_url for operations where the link in the OpenAPI descriptions is wrong.

tools/metadata

The tools/metadata package is a command-line tool for working with metadata. In a typical workflow, you won't use it directly, but you will use it indirectly through script/generate.sh and script/lint.sh.

Its subcommands are:

  • update-openapi - updates openapi_operations.yaml with the latest information from GitHub's OpenAPI descriptions. With --validate it will validate that the descriptions are correct as of the commit in openapi_commit. update-openapi --validate is called by script/lint.sh.

  • update-go - updates Go files with documentation URLs and formats comments. It is used by script/generate.sh.

  • format - formats whitespace in openapi_operations.yaml and sorts its arrays. It is used by script/fmt.sh.

  • unused - lists operations from openapi_operations.yaml that are not mapped from any methods.

Scripts

The script directory has shell scripts that help with common development tasks.

script/fmt.sh formats all go code in the repository.

script/generate.sh runs code generators and go mod tidy on all modules. With --check it checks that the generated files are current.

script/lint.sh runs linters on the project and checks generated files are current.

script/metadata.sh runs tools/metadata. See the Metadata section for more information.

script/test.sh runs tests on all modules.

Other notes on code organization

Currently, everything is defined in the main github package, with API methods broken into separate service objects. These services map directly to how the GitHub API documentation is organized, so use that as your guide for where to put new methods.

Code is organized in files also based pretty closely on the GitHub API documentation, following the format {service}_{api}.go. For example, methods defined at https://docs.github.com/en/rest/webhooks/repos live in repos_hooks.go.

Maintainer's Guide

(These notes are mostly only for people merging in pull requests.)

Verify CLAs. CLAs must be on file for the pull request submitter and commit author(s). Google's CLA verification system should handle this automatically and will set commit statuses as appropriate. If there's ever any question about a pull request, ask willnorris.

Always try to maintain a clean, linear git history. With very few exceptions, running git log should not show a bunch of branching and merging.

Never use the GitHub "merge" button, since it always creates a merge commit. Instead, check out the pull request locally (these git aliases help), then cherry-pick or rebase them onto master. If there are small cleanup commits, especially as a result of addressing code review comments, these should almost always be squashed down to a single commit. Don't bother squashing commits that really deserve to be separate though. If needed, feel free to amend additional small changes to the code or commit message that aren't worth going through code review for.

If you made any changes like squashing commits, rebasing onto master, etc, then GitHub won't recognize that this is the same commit in order to mark the pull request as "merged". So instead, amend the commit message to include a line "Fixes #0", referencing the pull request number. This would be in addition to any other "Fixes" lines for closing related issues. If you forget to do this, you can also leave a comment on the pull request like this. If you made any other changes, it's worth noting that as well, like this.

When creating a release, don't forget to update the Version constant in github.go. This is used to send the version in the User-Agent header to identify clients to the GitHub API.