[cmake-developers] CMakeFindDependencyMacro limitations

[Roger Leigh]

I've run into a few limitations in find_dependency.  I'm not sure if 
these are by design or could be fixed, so this is really a request for 
further explanation or design rationale.

The first issue is this:

   if (NOT ${dep}_FOUND)

This seems to be making the assumption that the found variable matches 
the dependency name, but the case used varies between modules and the 
name is case sensitive, from my reading of cmake-language.  Is this 
correct?  Even if so, should this optimisation be put here rather than 
in find_package itself?  If case sensitivity/naming is an issue, could 
the _FOUND variable be passed in as an argument, leaving the existing 
behaviour as the default if unspecified?

The reason for stripping EXACT isn't clear.  If my package has a strict 
requirement on another package, whether the caller has an exact 
requirement for the version of my package has no bearing on the 
requirements I have for my dependencies as far as I understand.  What's 
the reason for the existing behaviour?

Support for find_package arguments is limited to the dependency name and 
optionally the version.  I can understand why REQUIRED and related 
arguments are omitted--that is why find_dependency exists--but I'd quite 
like to be able to specify COMPONENTS where needed e.g. with FindBoost, 
and this is not currently possible.

I was wondering if we could perhaps make find_dependency handle and pass 
through /all/ find_package arguments, minus REQUIRED/QUIET, so that 
find_dependency can expose the additional functionality offered by 
find_package.  Some may not be useful, in which case they could be 
omitted, but some like COMPONENTS may be required for the find_package 
call to be useful.


Regards,
Roger