How to handle meson.override_dependency() with dependencies using modules and components

[dcbaker]

Consider a dependency like LLVM. The correct way to handle this in Meson is something like:

dep_llvm = dependency('llvm', modules : ['core', 'asmparser', 'asmprinter', 'disassembler'])

Nice and easy. However, there isn't really a way to handle this with meson.override_dependency(). It doesn't have modules, and the overridden dependency wont check that the correct modules are set.

[eli-schwartz]

Another example is the gtest wrap, iirc, with main: true

[dcbaker]

Yeah, and I'd like to change that to use either components or modules instead of main at some point, since that's more standard and likley more future proof.

[dcbaker]

I spent some time thinking about this, and I think the way to do this is:

meson.override_dependency(
  'name',
  'dependency'  # optional if components is given, if both are given this dependency is always provided. A place for a "core" module like QtCore.
  components : {
     'component1': declare_dependency(...),
     'component2': declare_dependency(...),
  },
)

Then when a dependency() call is given with modules or components (I need to go read the CMake code in Meson more closely to see if there actually is a fundamental difference or if we can collapse those...), the lookup code will return a new internal dependency using those components.