Trivial: Use public interface, not field names, in unittest ...

This would make moving this unittest to another module easier.

Trivial: Rename computePkgSuppliers to makePackageSuppliers ...

This is consistent with the naming of other factory functions.

Trivial: Shorten a few parameter names ...

The parameter names were repeating the type name,
which in a language like D does not make sense.

Trivial: Make `TestDub` non-final ...

There is no reason to limit inheritance on this class.

Allow to load dub.selections.json before Project instantiation ...

The aim of this commit is to have at least one constructor
for Project that does not perform IO. By moving the IO to the
`Dub` class, we can keep the dependency injection in `Dub`
and `PackageManager` only, and don't have to specialize `Project`.

Trivial: Remove a dependency to std.path ...

Use the Dub versions instead.

Trivial: Merge two related unittest in dub package ...

They both test computePackageSuppliers in the end.

Refactor loadConfig to not rely on class state ...

By making it take a parameter and return a value, we make it
more obvious what is being used and changed, and we document
that rootPath is the only class member being read,
which is a fair assumption for any method of Dub.

Trivial: Move TestDub behind a version (unittest) ...

As it should not be compiled in the final binary for releases,
it's just a class to help with unittests.

Dub: Make determineDefaultCompiler configurable ...

By making it an idempotent (albeit not pure) function,
we allow other classes to override it with their own logic.
One such example would be returning an hardcoded path every time.

Trivial: Simplify some deprecated code ...

While this code is deprecated, it is confusing as it is
using findPackageFile only to provide a worse error message
than one would have got by simply calling Package.load.

Change PackageSupplier interface to accept VersionRange ...

This is a leftover of the time when everything in dub accepted Dependency.
While the mess had been untangled, doing so on this interface proved harder,
as there is no good way to deprecate it in a fully backward-compatible manner
without introducing a lot of overhead (a new type). Instead, this uses
a middle ground approach, where the external implementers (which most likely
do not exists) would break (although the fix is trivial), but callers would not.

Move application code for static ctor in main module ...

This code could easily mess with library users as it has
some side effects, so move it somewhere it will only affect
the binary.

Trivial: Clear up some trailing whitespace

Implemented recipe files for dub #2684 (#2685) ...

Co-authored-by: Jan Jurzitza <gh@webfreak.org>

stabilize the cache directory structure

Add unittest to test collection of C sources and headers

Merge remote-tracking branch 'upstream/stable' into merge_stable

fix #2587

fix verbose logging crashing because of asserts

review adjustments

fix typo(s)

Merge remote-tracking branch 'upstream/stable' into merge_stable

reduce dependency on the working directory ...

Improves library API usage and bugs with the build generator

Fix various DDOC warnings

Use a central build cache for all build artifacts ...

Currently the central build cache is not configurable,
but as most build artifacts end up in `~/.dub/packages/` anyway,
this will be a positive change for users.

Rename UserConfiguration to Settings ...

The latter is more accurate, as we can have system settings
of type UserConfiguration.
This is also a push towards more consistent naming within dub,
as configuration is primarily used for package recipe 'configuration' field.

Move user settings to dub.data.settings ...

By moving it to its own module, we can ensure it's almost a leaf module.
We can also extend unittests to check different scenarios
without relying on integration test.

Rename localRepository to userPackages ...

The 'repository' terminology is confusing, and needs to be interpreted
from the PoV of the PackageManager to make sense. It is likely that
a naive read of this name would lead one to think of git repository,
as opposed to the repository where packages are stored.

Replace all instances of mkdirRecurse with ensureDir ...

All usages actually want to ensure the directory is present,
and don't care about having a separation between existence check
and creation.