This class now consolidates a lot of the logic that each external
dependency was duplicating in its class definition.
All external dependencies now set:
* self.version
* self.compile_args and self.link_args
* self.is_found (if found)
* self.sources
* etc
And the abstract ExternalDependency class defines the methods that
will fetch those properties. Some classes still override that for
various reasons, but those should also be migrated to properties as
far as possible.
Next step is to consolidate and standardize the way in which we call
'configuration binaries' such as sdl2-config, llvm-config, pkg-config,
etc. Currently each class has to duplicate code involved with that
even though the format is very similar.
Currently only pkg-config supports multiple version requirements, and
some classes don't even properly check the version requirement. That
will also become easier now.
The old caching was a mess of spaghetti code layered over pasta code.
The new code is well-commented, is clear about what it's trying to do,
and uses a blacklist of keyword arguments instead of a whitelist while
generating identifiers for dep caching which makes it much more robust
for future changes.
The only side-effect of forgetting about a new keyword argument would
be that the dependency would not be cached unless the values of that
keyword arguments were the same in the cached and new dependency.
There are also more tests which identify scenarios that were broken
earlier.
All our cached_dep magic was totally useless since we ended up using
the same identifier for native and cross deps. Just nuke all this
cached_dep code since it is very error-prone and improve the
identifier generation instead.
For instance, this is broken *right now* with the `type_name` kwarg.
Add a bunch of tests to ensure that all this actually works...
Closes https://github.com/mesonbuild/meson/issues/1736
Sometimes we want to restrict the acceptable versions to a list of
versions, or a smallest-version + largest-version, or both. For
instance, GStreamer's opencv plugin is only compatible with
3.1.0 >= opencv >= 2.3.0
In the case the main project set a subproject for a dependency another
subprojects uses, that other subproject should rather use the first
subproject rather that using native dependency.
For example in gst-all we set all GStreamer modules as subprojects
and, gst-plugins-base is set after gstreamer core, and
we want gst-plugins-base to always use GStreamer core from the subproject
and not the possibly avalaible native one.
And remove the InternalDependencyHolder class.
In some cases we need to know the type of dependency we are
dealing with. For example in GStreamer if the dependency
is not an internal one, then we need to get some env var
from pkg-config to know where to find some plugins necessary
to run some tests.
Niklas Claesson
Nirbheek Chauhan
Jussi Pakkanen
Thibault Saunier