[CMake] Empty item list in target_include_directories allowed?

[Gregor Jasny]

Hello,

I wonder if cmake should be able to parse the following project file:

   cmake_minimum_required(VERSION 2.8.11)
   project(Foo)

   add_library(mylib STATIC mylib.c)

   #set(a "a")

   target_include_directories(mylib PUBLIC ${a})


The help text for target_include_directories shows the following syntax:

   target_include_directories(<target> [BEFORE
       <INTERFACE|PUBLIC|PRIVATE> [items1...]
      [<INTERFACE|PUBLIC|PRIVATE> [items2...] ...])

So I would consider the item list in the [] brackets as optional.

Should I file a bug about it?

Thanks,
Gregor