Add a public initializer to RenderContentMetadata

[patshaughnessy]

Bug/issue #, if applicable: rdar://164210651

Summary

RenderContentMetadata, which is part of the Render JSON schema, doesn’t have a public initializer. This prevents other applications linking to Swift DocC from creating new metadata instances. This change adds a public initializer.

Dependencies

None.

Testing

Write a small Swift CLI executable program that links to Swift DocC, and then test that you can create an instance of RenderContentMetadata using this new public initializer.

let package = Package(
    name: "CreateRenderMetadata",
    platforms: [.macOS(.v15) ],
    dependencies: [
      .package(url: "git@github.com:patshaughnessy/swift-docc.git", branch: "r164210651-add-public-initializer-RenderContentMetadata"),
    ],
    targets: [
        .executableTarget(
            name: "CreateRenderMetadata",
            dependencies: [
                .product(name: "SwiftDocC", package: "swift-docc")
            ]
        ),
    ]
)

import SwiftDocC

@main
struct CreateRenderMetadata {
    static func main() {
        print("Hello, world!")
        let metadata = RenderContentMetadata()
        print(metadata)
    }
}

Checklist

Make sure you check off the following items. If they cannot be completed, provide a reason.

• Added tests
• Ran the ./bin/test script and it succeeded

[d-ronnqvist]

It's fine to have this test but I don't find it important to test that initializers set the properties of a structure because the compiler will already enforce that the initializer assigns a value to every property.

[patshaughnessy]

Thinking about this unit test some more, I've decided to rename & move the Swift file and test class to something more generic. I think this test file could be generally useful in the future for testing public access to various DocC API.

See: c587ac9

[d-ronnqvist]

I don't think running a test is a good mechanism for verifying that a piece of API is public. To my knowledge we don't do that for any other public API.

I personally don't think that having this test will meaningfully help us remember to make other future API in other types public and I think that the odds that this test protects us against unintentionally removing this API or changing it to a lower access level is abysmal.

I don't think it's harmful to have this test but I think the value it adds is fairly close to zero.

[d-ronnqvist]

To clarify; I'm not requesting that we remove this test, but I feel that the discussion around adding it has already cost more time and productivity that we'll ever regain from having this test.