[cmake-developers] target_include_directories() accepts only absolute paths ?

[Stephen Kelly]

Alexander Neundorf wrote:

> On Sunday 27 January 2013, Stephen Kelly wrote:
>> Alexander Neundorf wrote:
>> >> > Is there a reason why
>> >> > target_include_directories() should behave differently ?
>> >> 
>> >> That results from the semantics of the INCLUDE_DIRECTORIES property
>> >> and http://public.kitware.com/Bug/view.php?id=13188
>> > 
>> > Ok.
>> > This applies to setting the target property directly.
>> > But, I think target_include_directories() could still handle relative
>> > paths so that CMAKE_CURRENT_SOURCE_DIR is prepended before it is set as
>> > a target property.
>> 
>> Yes. However code like this would be ambiguous until generate-time:
>> 
>>  target_include_directories(foo PRIVATE bar)
>> 
>> Is bar a target or a directory? That means storing a longer string for
>> bar:
> 
> Simply saying that an existing directory with the given name has priority
> over a target with the same name would not be ok ?

Currently we do the opposite. First check if 'bar' is a target name, and if 
not, then treat it as a directory.

> This would mean that directories "shadow" targets (or only
> not-yet-existing targets), while the other way round targets shadow
> directories.

As directories should be set up front, that could be a good idea and could 
indeed allow us to determine at configure-time if 'bar' is a directory or 
might be a target.

>  
>>  
http://thread.gmane.org/gmane.comp.programming.tools.cmake.devel/5734/focu
>> s=5920
>> 
>>  https://gitorious.org/~steveire/cmake/steveires-
>> cmake/commit/6fcdd6e4d47d0469baad228a84ebb9269dceb488
>> 
>> I don't know if that has a big impact but it's an unfortunately long
>> string to have to store for such a small input.
>> 
>> We can also allow relative directories in a later release anyway. I'd
>> prefer at this point to be focussed on things which do have to be in this
>> release.
> 
> 
> Yes.

Although if we're going to change from 

 if (target) {} else if (directory) {}

to 

 if (directory) {} else if (target) {}

we should do that this release. 

I can have a look later/tomorrow depending on whether anything gets merged 
today. It would require refactoring which would conflict with my interface-
commands-lazy-target-check branch.

Thanks,

Steve.