Dub warning: sub-package refs should use path to dependency dir, not packagename:subpackage

[AMDphreak]

Summary

When projects depend on unit-threaded (e.g. transitively via dlangui), dub upgrade and dub build emit warnings:

Warning Sub package unit-threaded:exception, referenced by unit-threaded:assertions dub.package_.Package must be referenced using the path to its base package
Warning Sub package unit-threaded:from, referenced by unit-threaded:exception dub.package_.Package must be referenced using the path to its base package
...

DUB expects sub-package references to use the path to the dependency's directory rather than the packagename:subpackage form with a path to the root.

Minimal reproduction

1. Create a project that depends on a package pulling in unit-threaded (e.g. dlangui).
2. Run dub upgrade or dub build.

Expected

No DUB sub-package warnings.

Actual

Multiple warnings like:

Warning Sub package unit-threaded:exception, referenced by unit-threaded:assertions dub.package_.Package must be referenced using the path to its base package

Proposed fix

Change each sub-package's dub.sdl to use direct path references to sibling sub-packages:

From	To
dependency "unit-threaded:from" path="../.."	dependency "from" path="../from"
dependency "unit-threaded:exception" path="../.."	dependency "exception" path="../exception"
dependency "unit-threaded:assertions" path="../.."	dependency "assertions" path="../assertions"
dependency "unit-threaded:runner" path="../.."	dependency "runner" path="../runner"

(And similarly for mocks, property, integration, autorunner, behave.)

This eliminates all warnings. dub build and dub test continue to work as before.

Environment

• DUB 1.41.0 (and likely earlier)
• Windows 11 / PowerShell 7
• unit-threaded 0.7.55 (transitive dependency)