Bump Swift version

[Kyle-Ye]

Summary

Bump the Swift version Package.swift use to 5.4. And add a new 5.5 Package.swift file

Checklist

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

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

[Kyle-Ye]

Also upgrade the Swift version to make Markdown module to be able to use DocC for documentation

[Kyle-Ye]

Any idea on this PR @QuietMisdreavus ❤️

[Kyle-Ye]

Done, can we run tests on this PR?

[franklinsch]

@swift-ci please test

[franklinsch]

When I delete the Package@swift-5.5.swift file to force my toolchain to use Package.swift, I'm running into compiler errors I don't see on main, for example:

swift-markdown/Tests/MarkdownTests/Visitors/MarkupRewriterTests.swift:15:75: error: type 'Bundle' has no member 'module'
let everythingDocument = Document(parsing: try! String(contentsOf: Bundle.module.url(forResource: "Everything", withExtension: "md")!))
                                                                   ~~~~~~ ^~~~~~

[Kyle-Ye]

When I delete the Package@swift-5.5.swift file to force my toolchain to use Package.swift, I'm running into compiler errors I don't see on main, for example:

swift-markdown/Tests/MarkdownTests/Visitors/MarkupRewriterTests.swift:15:75: error: type 'Bundle' has no member 'module'
let everythingDocument = Document(parsing: try! String(contentsOf: Bundle.module.url(forResource: "Everything", withExtension: "md")!))
                                                                   ~~~~~~ ^~~~~~

It seems that Bundle.module is introduces on Swift 5.3 which is auto-generated for getting Package Resource.(You can check the file by recovering Package@swift-5.5.swift and Jump to Definition of module)

// Autogenerated: resource_bundle_accessor.swift
import class Foundation.Bundle

private class BundleFinder {}

extension Foundation.Bundle {
    /// Returns the resource bundle associated with the current Swift module.
    static var module: Bundle = {
        let bundleName = "swift-markdown_MarkdownTests"

        let candidates = [
            // Bundle should be present here when the package is linked into an App.
            Bundle.main.resourceURL,

            // Bundle should be present here when the package is linked into a framework.
            Bundle(for: BundleFinder.self).resourceURL,

            // For command-line tools.
            Bundle.main.bundleURL,
        ]

        for candidate in candidates {
            let bundlePath = candidate?.appendingPathComponent(bundleName + ".bundle")
            if let bundle = bundlePath.flatMap(Bundle.init(url:)) {
                return bundle
            }
        }
        fatalError("unable to find bundle named swift-markdown_MarkdownTests")
    }()
}

See https://developer.apple.com/documentation/swift_packages/bundling_resources_with_a_swift_package

https://github.com/apple/swift-package-manager/blob/77f7ac7dc49c921a5241f5e79b4bd6fa52795b25/Sources/Build/BuildPlan.swift#L661-L707

[Kyle-Ye]

I think that's why people are not using the content of "Everything.md" to init the everythindDocument properly since the original swift version was 4.2

[Kyle-Ye]

It seems we have 3 options to go, which one do you prefer? (Personally, I prefer option2, but option3 is also acceptable)

1. Delete the md file. use hard-coded text
2. Use md resource file. Update the Package.swift to 5.3 (Release on Sep 17, 2020)
3. Use md resource file. Add a fallback to provide Bundle.module before swift 5.3

[Kyle-Ye]

cc @franklinsch

[franklinsch]

Thanks for investigating these options! I think updating to 5.3 is reasonable (option 2) since it was released more than a year ago.

[Kyle-Ye]

Thanks for investigating these options! I think updating to 5.3 is reasonable (option 2) since it was released more than a year ago.

Done. Could you please help me run test on this?

[franklinsch]

@swift-ci please test this

[Kyle-Ye]

@swift-ci please test this

Looks like it does not trigger the Test check. Maybe it should be "@swift-ci please test"?

[franklinsch]

@swift-ci please test

[franklinsch]

@swift-ci please test this

Looks like it does not trigger the Test check. Maybe it should be "@swift-ci please test"?

Yes, just noticed this as well 😄

[Kyle-Ye]

Any other suggestion on this? Or could we merge it with your approval?

[franklinsch]

Looking at the CI logs, it looks like it's now emitting this warning:

FormatCommand.swift:133:19: note: use 'run' instead

Can we resolve this before merging this PR?

[franklinsch]

Actually, I see that warning happened before the changes of this PR, so we can resolve this as part of another PR.

[franklinsch]

Thanks @Kyle-Ye for another awesome PR! 🙌

[Kyle-Ye]

Looking at the CI logs, it looks like it's now emitting this warning:

FormatCommand.swift:133:19: note: use 'run' instead

Can we resolve this before merging this PR?

It seems to be fixed by this PR.(Which is blocked by this PR before) #3