Another commit in my quest to rid InterpreterBase from all higher
level object processing logic.
Additionally, there is a a logic change here, since `str.join` now
uses varargs and can now accept more than one argument (and supports
list flattening).
This assert causes several type checkers (both mypy and pyright) to
force `obj` to be a base `HoldableObject` instead of the specialized
object. Since the check itself may still be valuable as we don't have
fully type annotation coverage it's simply been removed when type
checking to aid in type specialization.
This commit introduces a new type of `HoldableObject`: The
`SecondLevelHolder`. The primary purpose of this class is
to handle cases where two (or more) `HoldableObject`s are
stored at the same time (with one default object). The
best (and currently only) example here is the `BothLibraries`
class.
As a side-effect from #8885 `find_program()` returns now `Executable`
objects when `meson.override_find_program` is called with an
executable target. To resolve this conflict the missing methods
from `ExternalProgram` are added to `BuildTarget`.
Daniel Mensinger
Dylan Baker
Xavier Claessens