Use carthage xcframeworks

[yonaskolb]

This enables XcodeGen to look up the xcframeworks that Carthage 0.37 builds.
This PR is still a work in progress, but put up for reference.
Resolves #1006

For now it requires adding carthageXCFrameworks: true to the spec options

[freddi-kit]

Review Ongoing

[freddi-kit]

↓ may be correct?

Suggested change

	let directlyEmbedCarthage = target.directlyEmbedCarthageDependencies ?? project.options.carthageXCFrameworks || targetSupportsDirectEmbed
	let directlyEmbedCarthage = target.directlyEmbedCarthageDependencies ?? (project.options.carthageXCFrameworks || targetSupportsDirectEmbed)

This makes one failed test passing.

[kateinoigakukun]

IMHO we don't need to handle carthage dependency specially any more because XCFramework removed carthage copy-framework step. We can add carthage dependency as a normal framework dependency like: framework: Carthage/Build/Alamofire.xcframework.

Yeah, but making things simple often leads some redundancy, so I understand the demand of shorthand.

But even if we provide a shorthand for framework: Carthage/Build/Alamofire.xcframework, we should separate API completely in the aspect of backward compatibility, I think.
IIUC, carthage build will produce XCFramework by default in the near future. So we may need to set carthageXCFrameworks true by default.

However, in that case, it will not be compatible with the old project.yml which uses carthage: Alamofire without explicit carthageXCFrameworks and doesn't use xcframeworks. If that project will update XcodeGen to the future version which enables carthageXCFrameworks by default, xcodeproj can't be generated without explicit carthageXCFrameworks: false.

On the other hand, if we won't make carthageXCFrameworks true by default, we have to write carthageXCFrameworks: true for the rest of our life.

So we need to re-think we should provide a shorthand or not, and the shorthand API should be separated from the current API or not.

[CraigSiemens]

I tried this out with our project and an issue I'm noticing is that since carthage supports getting precompiled frameworks, it's possible to get a mix of xcframeworks and frameworks. This flag seems to assume everything will be available as a xcframework.

As far as I can tell, there isn't a great way to know whether a dependency will be a xcframework when the project is generated. The only ways I can think of would be:

• Use the currently added flag as a global default, allow each dependency to override that setting as needed with an isXCFramework: {true|false} or type option.
• At project generation time, look in the Carthage/Build folder to see whether it's a xcframework or a framework
  • May slow down the project generation a bit
  • Would require that the carthage dependencies are build before the project is generated, which isn't needed currently.

[lsh-silpion]

Hi there, is there any progress here?