Conflicting dependency resolution

[diegomrsantos]

Consider the following nimble files

Project A:

version = "1.1.0"

requires "B >= 0.1.4", "C >= 0.0.5 & <= 0.1.0"

Project B:

version = "0.1.4"

requires "C"

Also consider Project C has versions 0.1.0 and 0.2.1 available.

If nimble install A is run, it fails with Error: Cannot satisfy the dependency on C 0.1.0 and C 0.2.1. The version 0.2.1 is installed first for B and later 0.1.0 for A.

Is it expected? When no version is specified, does it mean any version? If so, why hasn't only C 0.1.0 been installed, what would satisfy both A and B requirements?

[xTrayambak]

That's a fairly complicated problem right there. What should the behaviour be? I believe it's fine as it is right now, it's how most languages' package managers handle it.

[diegomrsantos]

I believe installing onlyC 0.1.0 would satisfy both project A and B constraints on C version.

[diegomrsantos]

It seems Nimble is satisfying the dependencies' version constraints (and their transitive dependencies) greedily and locally, instead of globally, considering the whole set of constraints.

[xTrayambak]

I'm fairly sure that's a bug. Nimble will choose any version it can find if none is explicitly provided.