Build fail due to optional dependency

[andre2007]

Background information to understand the issue: I am creating a XMake build infrastructure for the D Programming Language. There are some "golden rules" which I have to follow. I am not allowed to access the internet (code.dlang.org) during the build.

The consequence is, all dependencies have to be included. In my dub project I use the dub package "d-unit" which has an optional dependency to "unit-threaded" (https://github.com/linkrope/dunit/blob/master/dub.json#L24)

I extracted the d-unit zip file (https://github.com/linkrope/dunit/archive/v0.8.1.zip) into the main dub folder and added the dependency with "path" information.

"dependencies": {
		"d-unit": {"path":"dunit-0.8.1"}
	},

As mentioned, the dub build command is not allowed to use the internet and therefore has the skip argument:

dub build --skip-registry=all

The build fails due to the optional dependency to unit-threaded

Could not find a valid dependency tree configuration: Package d-unit contains invalid dependency
unit-threaded (no version candidates)

My proposal is to have a lazy dependency resolvement. As long as a configuration is not used, the dependencies should not be downloaded.

[andre2007]

I just learned there is a parameter --nodeps (Do not check/update dependencies before building) for dub build. Although I use this parameter, the same error message is shown. Is this the correct behavior of --nodeps? I understand the description, that the check which causes the error message should not occur.

[andre2007]

Pull request from skoppe #1148

[Geod24]

This is another duplicate of #1217