[SR-5693] SemVer variant incompatible with SwiftPM

[BasThomas]

Previous ID	SR-5693
Radar	rdar://problem/40205279
Original Reporter	@BasThomas
Type	Bug

Environment

Apple Swift version 3.1 (swiftlang-802.0.53 clang-802.0.42)
Target: x86_64-apple-macosx10.9
/Library/Developer/CommandLineTools/usr/bin/lldb "--repl=-enable-objc-interop -sdk /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -color-diagnostics"
Welcome to Apple Swift version 3.1 (swiftlang-802.0.53 clang-802.0.42).

Additional Detail from JIRA

Votes	0
Component/s	Package Manager
Labels	Bug
Assignee	None
Priority	Medium

md5: 8fa4044d8e9412f2d3bde2d32cebba5f

Issue Description:

Although a version like 9.0.0-alpha.1 is compatible with SemVer, it is not supported in SwiftPM, which errors with "unsatisfiable". More information can be found in this issue over at Moya.

[aciidgh]

unsatisfiable means that the resolver was not able to find a valid solution. The dependency resolution around prerelease tags in Swift 3 toolchain is broken. Can you try the same thing with a swift 4 toolchain? You don't need to update the manifest, just the toolchain.

If that also fails, can you also post the exact manifest you're having problems with?

Thanks!

[BasThomas]

If I can find the time I'd gladly test with the Swift 4 toolchain. In the meantime, it seems like the specific issue was actually a git bug, wherein the tag name and branch name are the same, causing the resolver to fail. I'd guess we can close the issue then.

If this is something that can be resolved via SwiftPM, that would be awesome. If not, improving the error messaging (again, if possible) would be another improvement.

Thanks for the update, Ankit!

[aciidgh]

@swift-ci create

[krzyzanowskim]

It's been almost 5 years now since it's broken, I wonder whether SwiftPM documentation at https://www.swift.org/package-manager/ should still state that it follows SemVer, while it's not. wdyt?

[WowbaggersLiquidLunch]

The version string "9.0.0-alpha.1" in the original bug report should be parsed correctly since #3486 and swiftlang/swift-tools-support-core#214. There are still some bugs in the parsing logic that deviates form SemVer's (but I forgot what exactly). Last year I had planned to first fix DocC SymbolKit's SemVer implementation swiftlang/swift-docc-symbolkit#36, then carry the same change into DocC's, then adapt it to fix SwiftPM/TSC's. I just haven't gotten around to it yet. (Maybe I can pick it up this weekend or next week, but no promises)

[krzyzanowskim]

thanks!

btw. I just tried "2.0-beta.1" and "2.0.0-beta.1" and it didn't work in Xcode SwiftPM

[WowbaggersLiquidLunch]

Are you using the version string in an Xcode project or a Swift package? If it's the former, then I guess the bug might be because Xcode doesn't use SwiftPM/TSC's version parser, as discovered by @SDGGiesbrecht in #6143.

[tomerd]

cc @abertelrud if this is an Xcode specific issue, lets track it as such.