admin.md

Admin Manual for Definitely Typed

Welcome! This is a resource for the person who is on call for Definitely Typed. The TypeScript team always has someone assigned to Definitely Typed duty, where they do a week on-call. You can see the schedule here.

When on-call, your goal is to try to keep on top of the many open PRs for Definitely Typed; they are categorized into different sections inside the Projects board on this repo.

You should scan from left to right through the boards, and ideally try to start at the oldest PR in a section and work your way through to the newest. There is a tool: focus-dt which can help with this.

Our goals are to provide a stable, high-quality ecosystem of type definitions and that requires the compiler team making sure that a PR does not break the ecosystem. This work isn't a code review in the usual sense, but an assessment of how well the changes fit the rest of the type definitions and if it could break builds for our users or our systems. With the impact understood, your job is to delegate to the people who actually know how to review the code: users of the library who have agreed to look after the types.

Looking at a PR

For a quick TLDR overview, you can read these slides.

Some key concepts:

• Popular packages can break more installs, and will need more time and focus
• There are a handful of authors who have shipped a lot of high-quality contributions who you can happily delegate to

Project board columns

• Needs Maintainer Action: PRs that cannot be dismissed with a blessing
• Needs Maintainer Review: Main maintainer queue column
• Other: Something went wrong, PRs can pop up there for a short time before the test results are in
• Waiting for Author to Merge: All good, and the owner can self-merge their PR
• Needs Author Action, Recently Merged, Waiting for Code Reviews: Self describing

"Blessing" a PR

You can control the life-cycle of PRs via "blessings", which are implicit operations done without providing a review that can be misinterpreted as an expert review.

TL;DR:

• To dismiss a PR in "Needs Maintainer Review", move it to "Waiting for Code Reviews".
• To dismiss a PR in "Needs Maintainer Action", move it to "Waiting for Author to Merge".
• To undo either of these, move them to any other column.

• If a PR requires a maintainer review, you can fulfill this requirement by a "review-blessing": you do that by moving the PR to the Waiting for Code Reviews column (using the drop-down in the "Projects" section on the right). This is especially relevant in cases where a maintainer review is needed because of a technical requirement like no tests, suspicious config edits etc.: in such cases you can review-bless the PR in case the config edit is fine, the change is small or doesn't modify types etc. Note that it only dismisses the maintainer review requirement, so the PR will continue the usual flow, and will wait for approvals as needed.

• If a PR requires a maintainer action, you can move it to the Waiting for Author to Merge column to "merge-bless" it: make the bot offer the author to self-merge. This is particularly useful in cases where a PR author is unsure about something, and is trying to solicit review from owners or library authors: it makes it possible to defer the decision when to merge to the author, instead of starting an "are you ready" discussion.

You can use either of these blessings in other cases too, the above are just the common use cases. A review-blessing is only good to satisfy a maintainer review requirement (so other reviews will be needed), and a merge-blessing will usually make a PR self-mergeable, but it will still wait until a PR is unconflicted and the CI is green.

Like a review, both kinds of blessings will be dismissed if the PR is updated. You can also undo a blessing by moving a PR to any other column.

Amending an existing Definitely Typed Package

An ideal PR to a DT package looks like:

• A link in the PR description to the API being added
• Only additions to the existing types
• Test code which covers the existing use case

Most of the PRs are like this, in which case a review for that PR should be pretty quick. Look through the code changes, then see if there are comments asking for the merge to be delayed. If not, then you're good to merge. You can then leave a thanks comment and hit the merge button.

Constraints which you should consider:

• Will the PR break existing code?

  • This can sometimes be hard to decipher from the diff, e.g., an addition-only PR may break superclasses of a class
  • We try to make sure that types are a semver match on major.min for the library they represent
  • A build breaking change therefore can be a trade-off where you have to talk with the library maintainer, and get their sign-offs that it is worth it

• Is it popular? (e.g., do you recognize it) if so, it should probably have two sign-offs

• The PR has merge conflicts, you can try edit the PR using the GitHub UI if it's a trivial change, then come back tomorrow

• The PR has no tests, possibly the package on DT hasn't got tests set up. You can decide if that's a blocker or not depending on how likely the code is going to break existing code

• The tslint.json does not have exceptions to the rules in it

• Strict mode is strict: true or equivalent four (five?) settings in tsconfig.json

• Make sure export default is actually default in the source.

  // Cannot have `export default` in the dts
  module.exports = {
    thing: () => "hello world"
  }

  vs

  // Can import via `export default`
  module.exports.default = {
    thing: () => "hello world"
  }

  react-* packages get a pass on this. Their tsconfig.json should never have esModuleInterop: true, which would hide the above issue.

New Definitely Typed Package

• Is the author also a maintainer of the library? If so, they could use --declaration and --allowJs in TypeScript to generate their types.

Useful Repos and Links

The process of handling PRs:

• DT projects — an automated board saying where open PRs live
• dt-merge-bot — the bot which sets the labels on PRs, and update's project status
• focus-dt — a tool which controls chrome to load up the next PR to review, so you can focus
• dtslint — the CLI tool used to validate PRs on Definitely Typed

The process of deploying changes:

• types-publisher — when a PR is merged, types-publisher moves the contents to npm/GitHub Package Repository
• CI — the build pipelines on Azure which does most of the work

Recommendations we make:

• dts-gen — a tool for creating a DT folder automatically