We're having a case where we have some launch files which optionally include other launch files based on an environment variable being set. These are failing the test created by roslaunch_add_file_check, since it doesn't respect the conditional and attempts to resolve all include elements without regard for context.

This can be reproduced trivially by a launch file such as this, which launches just fine, but will (wrongly, in my opinion) fail the roslaunch check:

<launch>
  <include if="0" file="does/not/exist.launch" />
</launch>

Interestingly, roslaunch_add_file_check totally does resolve $(arg), $(env), $(optenv), etc, so this really does seem to be an issue with just the conditionals.