Maintainer Guidelines

This guide is for maintainers. These special people have write access to Homebrew’s repository and help merge the contributions of others. You may find what is written here interesting, but it’s definitely not a beginner’s guide.

Maybe you were looking for the Formula Cookbook?

Quick checklist

This is all that really matters:

Checking dependencies is important, because they will probably stick around forever. Nobody really checks if they are necessary or not. Use the :optional and :recommended modifiers as appropriate.

Depend on as little stuff as possible. Disable X11 functionality by default. For example, we build Wireshark, but not the heavy GTK/Qt GUI by default.

Homebrew is about Unix software. Stuff that builds to an .app should probably be in Homebrew Cask instead.

Naming

The name is the strictest item, because avoiding a later name change is desirable.

Choose a name that’s the most common name for the project. For example, we initially chose objective-caml but we should have chosen ocaml. Choose what people say to each other when talking about the project.

Add other names as aliases as symlinks in Aliases in the tap root. Ensure the name referenced on the homepage is one of these, as it may be different and have underscores and hyphens and so on.

We mostly don’t allow versions in formula names (e.g. bash4.rb); these should be in the homebrew/versions tap. (python3.rb is a rare exception, because it’s basically a “new” language and installs no conflicting executables.)

For now, if someone submits a formula like this, we’ll leave them in their own tree.

Merging, rebasing, cherry-picking

Merging should be done in the Homebrew/brew repository to preserve history & GPG commit signing, and squash/merge via GitHub should be used for formulae where those formulae don’t need bottles or the change does not require new bottles to be pulled. Otherwise, you should use brew pull (or rebase/cherry-pick contributions).

Don’t rebase until you finally push. Once master is pushed, you can’t rebase: you’re a maintainer now!

Cherry-picking changes the date of the commit, which kind of sucks.

Don’t merge unclean branches. So if someone is still learning git and their branch is filled with nonsensical merges, then rebase and squash the commits. Our main branch history should be useful to other people, not confusing.

Testing

We need to at least check that it builds. Use the Brew Test Bot for this.

Verify the formula works if possible. If you can’t tell (e.g. if it’s a library) trust the original contributor, it worked for them, so chances are it is fine. If you aren’t an expert in the tool in question, you can’t really gauge if the formula installed the program correctly. At some point an expert will come along, cry blue murder that it doesn’t work, and fix it. This is how open source works. Ideally, request a test do block to test that functionality is consistently available.

If the formula uses a repository, then the url parameter should have a tag or revision. urls have versions and are stable (not yet implemented!).

Common “gotchas”

  1. Ensure you have set your username and email address properly
  2. Sign off cherry-picks if you amended them (GitX-dev can do this, otherwise there is a command-line flag for it)
  3. If the commit fixes a bug, use “Fixes #104” syntax to close the bug report and link to the commit

Duplicates

The main repository avoids duplicates as much as possible. The exception is libraries that macOS provides but have bugs, and the bugs are fixed in a newer version. Or libraries that macOS provides, but they are too old for some other formula. The rest should be in the homebrew/dupes tap.

Still determine if it’s possible to avoid the duplicate. Be thorough. Duped libraries and tools cause bugs that are tricky to solve. Once the formula is pulled, we can’t go back on that willy-nilly.

If it duplicates anything ask another maintainer first. Some dupes are okay, some can cause subtle issues we don’t want to have to deal with in the future.

Dupes we have allowed:

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It may be enough to refer to an issue ticket, but make sure changes are clear so that if you came to them unaware of the surrounding issues they would make sense to you. Many times on other projects I’ve seen code removed because the new guy didn’t know why it was there. Regressions suck.

Don’t allow bloated diffs

Amend a cherry-pick to remove commits that are only changes in whitespace. They are not acceptable because our history is important and git blame should be useful.

Whitespace corrections (to Ruby standard etc.) are allowed (in fact this is a good opportunity to do it) provided the line itself has some kind of modification that is not whitespace in it. But be careful about making changes to inline patches—make sure they still apply.

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