DART_INCLUDE_DIRS doesn't include the dependent include directories

[jslee02]

Bug Report

Please answer the following questions for yourself before reporting a bug.

• [x] I checked the documentation and the forum but found no answer.
• [x] I checked to make sure that this issue has not already been filed.

Environment

Select the following information.

• DART version: 6.8.4 (installed from PPA)
• OS name and version name(or number): Ubuntu 16.04
• Compiler name and version number: GCC 5.4.0

Expected Behavior

DART_INCLUDE_DIRS should include all the include paths of the DART dependencies.

Current Behavior

DART_INCLUDE_DIRS only includes /usr/include

Possible Solution

We should either fix this or drop supporting CMake variables in favor of imported targets (related issue: https://github.com/dartsim/dart/pull/1209).

[mxgrey]

Since DART_LIBRARIES is already being stuffed the imported targets, the user should get all the headers they need just by linking their target to DART_LIBRARIES. They shouldn't even need to explicitly use DART_INCLUDE_DIRS at all anymore.

Do you have a situation where the configuration/build is actually failing?

[jslee02]

Since DART_LIBRARIES is already being stuffed the imported targets, the user should get all the headers they need just by linking their target to DART_LIBRARIES. They shouldn't even need to explicitly use DART_INCLUDE_DIRS at all anymore.

Yeah, that is what I expect as well.

Do you have a situation where the configuration/build is actually failing?

I don't have, but one user reported that. I'm clarifying if the user linked the imported targets using DART_LIBRARIES. In any case, it would be good to either fix DART_INCLUDE_DIRS and support it; or remove it entirely and encourage users to use DART_LIBRARIES instead.

[mxgrey]

If we're going to choose between fixing it and removing it, I would remove it since it doesn't accomplish anything.

The one catch with removing it is that some users might be confused when it shows up completely blank, and might be misled into thinking that something in their configuration or installation is broken.

[jslee02]

Good point. I meanted making DART_INCLUDE_DIRS as an undefined variable, but it seems CMake teats an undefined variable as an empty variable in target_link_libraries sliently. The user can be confused unless they checks if the variable is defined using if(DEFINED ...).