`sourcePaths` with `platform` restriction is ignored when library is used as an external dependency

[ZILtoid1991]

Works without an issue when used from subpackages, but is ignored once the package is a dependency for another one.

Offending line: https://codeberg.org/ZILtoid1991/iota/src/commit/aa4588be7abcecc2366d047fe5a3dccf22dbcc5e/dub.sdl#L22

[Shubham-Padkonde]

I checked a minimal local dependency on current DUB master (fb8f899) with LDC 1.43.0 on Linux. Platform-specific sourcePaths are used to build the dependency, but they do not add module import paths for its consumer.

My dependency has extra/example.d and:

{
  "name": "platform-dependency",
  "targetType": "library",
  "sourcePaths-linux": ["extra/", "source/"]
}

The dependency builds, but an application importing example fails with unable to read module example; the dependency import search path contains only source/. Adding "importPaths-linux": ["extra/", "source/"] makes the application compile and run successfully, without changing DUB.

This matches the documented distinction between source and import paths. Could the platform-specific directories in the linked SDL also need matching importPaths ... platform="osx" / platform="windows" entries? I have not built the full iota project or tested those two platforms, so this is a narrowed reproduction rather than a claim that the original report is fully resolved.

Investigation and this comment were prepared with Codex assistance.