SPM cannot resolve dependency graph


I have an issue where, in one package I forked, I modified Package.swift so that one dependency points to the master branch of another package I forked.

.package(url: "https://github.com/adtrevor/http.git", .branch("master")),

Unfortunately, the package resolution errors with an unclear message:

websocket$ swift package show-dependencies

Fetching https://github.com/adtrevor/http.git

Updating https://github.com/apple/swift-nio-ssl.git

Updating https://github.com/vapor/core.git

Updating https://github.com/apple/swift-nio.git

Updating https://github.com/vapor/crypto.git

Updating https://github.com/apple/swift-nio-zlib-support.git

Updating https://github.com/apple/swift-nio-ssl-support.git

Updating https://github.com/apple/swift-nio-http2.git

Updating https://github.com/apple/swift-nio-extras.git

Updating https://github.com/apple/swift-log.git

error: dependency graph is unresolvable; found these conflicting requirements:


https://github.com/adtrevor/http.git @ master

I don't understand at all what is happening. Is this a bug or am I doing something wrong?

Thank you

cc: @Aciid Is this something that will get better error messages similar to SwiftPM: what's the conflict? ? I can't find at all the cause with the current error :confused:

There is work going on in SwiftPM that will dramatically improve the dependency resolution error messages. It's not all there yet but I just ran the new resolver on your package and got this:

because http @master depends on swift-nio-ssl ^2.0.0 and websocket depends on http @master, websocket requires swift-nio-ssl.
And because websocket depends on swift-nio-ssl ^1.3.1 and root depends on websocket, version solving failed.

To pin point, here are the conflicts:


Thanks a lot! Nice to see the improvement for the messages! :)

@kiliankoe might be encouraged to see that his work already came in useful. (You too Ankit, but you already know.)


This also not working properly on my iOS device. It is showing iTunes has an invalid signature. Please help me to fix this properly.

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