Re: [OE-core][master][PATCH] cmake: Unset CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES variable definition from toolchain file

[Richard Purdie <richard.purdie@linuxfoundation.org>]

On Wed, 2023-11-29 at 16:58 +0530, aszh07 wrote:
> From: Zahir Hussain <zahir.basha@kpit.com>
> 
> As discussion in [YOCTO #14717] cmake contains a OEToolchainConfig.cmake
> file to configure the toolchain correctly in cross-compile build for recipes
> using cmake.
> 
> The variable CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES value updates incorrectly
> during do_compile the code. Due to this getting sporadic error like below,
> 
> fatal error: stdlib.h: No such file or directory
> >    75 | #include_next <stdlib.h>
> >       |               ^~~~~~~~~~
> > compilation terminated.
> > ninja: build stopped: subcommand failed.
> > WARNING: exit code 1 from a shell command.
> 
> As cmake already correctly initializes the variable from environment, So we have to
> unset it in the toolchain file to avoid overwriting the variable definition again.
> 
> Signed-off-by: aszh07 <mail2szahir@gmail.com>
> Signed-off-by: Zahir Hussain <zahir.basha@kpit.com>
> ---
>  meta/recipes-devtools/cmake/cmake/OEToolchainConfig.cmake | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/meta/recipes-devtools/cmake/cmake/OEToolchainConfig.cmake b/meta/recipes-devtools/cmake/cmake/OEToolchainConfig.cmake
> index d6a1e0464c..6434b27371 100644
> --- a/meta/recipes-devtools/cmake/cmake/OEToolchainConfig.cmake
> +++ b/meta/recipes-devtools/cmake/cmake/OEToolchainConfig.cmake
> @@ -18,3 +18,6 @@ file( GLOB toolchain_config_files "${CMAKE_CURRENT_LIST_FILE}.d/*.cmake" )
>  foreach(config ${toolchain_config_files})
>      include(${config})
>  endforeach()
> +
> +unset(CMAKE_C_IMPLICIT_INCLUDE_DIRECTORIES)
> +unset(CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES)

Can we add some kind of test cases for cmake so that we don't go in
circles with these bugs?

Cheers,

Richard