PackageTemplate

A template for Swift packages on GitHub

It is a little opinionated, but mostly just stuff that I've found useful. Feel free to customize as needed. And if you have ideas for ways to improve this, open an issue or PR!

The golden rule: your package name should not be the same as a public type within your package. This can result in a ridiculous situation where the compiler cannot distinguish between the module name and type name, and has made my life difficult in the past. Someone please send me a blog post or something about this and I will link to it.

I'm a fan of CapitalCase. I don't think the word "Swift" should be in the name.

Neither of them currently apply to Swift

GitHub offers a lot of control here. I've started doing a bare minimum: protecting the main branch from accidental force pushes and deletion. You can do this easily with Settings > Code and automation > Branches. Add a rule for main with all check boxes unchecked and done.

This is non-optional. Many users, for very valid reasons, will not even look at a package without a license. GitHub makes this easy. I have been a long-time user of the BSD 3-clause license. It is very permissive, like MIT, but also specifically limits implicit endorsements from those involved.

I'm, in general, not a fan of viral licenses, especially when that virality applies to linking. However, I appreciate why that was designed the way it was. Preventing open source abuse and exploitation is important and your choice of license can really matter there.

"Let's be excellent to each other" is great! But, having a concrete set of rules about what that actually means, and what happens should those rules be broken is important. The Contributor Covenant has become popular and I think it is a great choice.

I like throwing a few badges up on my repos to provide some glanceable information. I think it is easy to go overboard here, but you should also feel good about making this your own!

Many people find explicit package installation instructions helpful, even just for convenient copy-paste into another Package.swift file. I like to include them, but you have to watch out for two things.

• you should regularly bump your version number
• packages that contain a library of a different name need a more-explicit dependency specification

dependencies: [
    .package(url: "https://github.com/ChimeHQ/PackageTemplate", from: "1.0.0")
],
targets: [
    .target(
        name: "UseCoreFunctionality",
        dependencies: ["PackageTemplate"]
    ),
    .target(
        name: "UsesDifferentProduct",
        dependencies: [.product(name: "AnotherProduct", package: "PackageTemplate")]
    ),
]

If you are using GitHub sponsorships, you know how this works. But just in case, please do not copy my .github/FUNDING.yml into your own project.

For a long time, I thought leaving platforms empty was the most compatible thing to do. However, this leaves the effective platform/version up to the compiler. And, that can produce surprising results that change over time. Being explicit is best.

This allows two things: better concurrency checking and visionOS support. Using concurrency without compiler checks is a bad idea. And you may be using it without even realizing it. I have this dialed all the way up for all targets. It is slightly ugly, but I prefer to have maximum checking without having to manually adjust if I add targets.

let swiftSettings: [SwiftSetting] = [
    .enableExperimentalFeature("StrictConcurrency"),
    .enableUpcomingFeature("DisableOutwardActorInference"),
    .enableUpcomingFeature("IsolatedDefaultValues"),
]

for target in package.targets {
    var settings = target.swiftSettings ?? []
    settings.append(contentsOf: swiftSettings)
    target.swiftSettings = settings
}

GitHub actions are mostly great. But there are two things that make them very un-great. GitHub is incredibly slow about bringing up new versions of macOS. This means "macOS-latest" is never the latest released version of macOS. That alone might be a problem for a package that supports macOS. But, it can also impact the default Xcode version.

The second problem is simulator names change and xcodebuild makes it very hard to not care.

I have given up relying on defaults here, and I always make things explicit. Unfortunately this means manual maintenance, especially around WWDC.

• Host OS
• Xcode version
• Simulators names

If you have tricks/hacks/custom actions to make this better, please let me know.

Note! If your package contains more than one entry it its products array, you'll need to append -Package to the scheme name to get xcodebuild tests to work.

The SPI is a no-brainer.

If I have an idea for a library, I always do some searching on SPI first.

Kind of like a mini CI. SPI will build your packages for many swift/platform combinations. I think making it clear up front what platforms your package supports is very useful.

Perhaps the most underrated feature. If you include DocC in your package, SPI will host it for you. You need a .spi.yml file for this to work.

For a very long time, I thought tabs vs spaces was a stupid thing to get worked up about. Then one day I learned that tabs can offer accessibility improvements for low-vision people. And that same advantage also helps to style code the way people prefer. So I switched to tabs and I encourage you to do same.

Despite Xcode not supporting it, I still think including editorconfig support is a good idea. I'm a dreamer.

I'd love to hear from you! Get in touch via mastodon, an issue, or a pull request.

By participating in this project you agree to abide by the Contributor Code of Conduct.