Inexplicable Swift Package Resolution Error

I have a large old macOS app project (15 targets, 15 years old) in a workspace. It was building fine until yesterday afternoon, when I attempted to do a Git Stash in Xcode. This caused Xcode 16.1 Beta which I was using to crash, and after that this Xcode crashed on launch. Trying Xcode 15.4, 16.0 Beta 6 and 16.1 Beta, in macOS 15 Beta, the only Xcode I can get to launch now is 16.0 Beta (further details of that are available upon request, but not my problem at this time).

My current problem is that the first Build task, Package Resolution, now fails with this error message:

Failed to resolve dependencies
Dependencies could not be resolved because root depends on 'swift-argument-parser' 1.3.0..<2.0.0 and root depends on 'swift-argument-parser' 0.4.3..<1.0.0.

Indeed, the project has a Package Dependency on swift-argument-parser 1.3.0 < 2.0.0. But I have no idea where Xcode is getting the other version string "0.4.3" from. And I don't know what "root" is being referred to, and whether or not it is the same "root" in both clauses of that error message. I have searched the relevant .pbxproj file, and indeed the whole project folder using BBEdit's Multi-File Search, and it could not find the text string "0.4.3" in this context anywhere. Where might that "0.4.3" be coming from?

Thank you.

Clean Build Folder does not change the error. Nor does trashing the project's DerivedData folder in Finder.

Eureka, probably. My workspace includes the Sparkle updater (sparkle-project.org), which is in a different project folder, and depends on swift-argument-parser 0.4.3. Maybe updating Sparkle will fix the problem.

Yes, if I change the swift-argument-parser in the Sparkle project to match that in my project, the problem is solved.

But my project does indeed need swift-argument-parser version 2.x. I suppose I could test Sparkle with swift-argument-parser 2.x and submit a pull request to Sparkle if it passes. But I kind of think I should file a bug against Xcode or Swift Package Manager: Should these tools not be able to handle different projects in a workspace requiring different versions of the same remote package? Or is there a better way to fix this of which I am not aware?

Inexplicable Swift Package Resolution Error
 
 
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