Re: [Qemu-devel] [PATCH 1/2] build-sys: define QEMU_SRC_PATH

[Michael Roth <mdroth@linux.vnet.ibm.com>]

Quoting marcandre.lureau@redhat.com (2016-06-14 08:16:53)
> From: Marc-André Lureau <marcandre.lureau@redhat.com>
> 
> Define QEMU_SRC_PATH in config-host.h, to ease accessing of tests data
> files.
> 
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

I know this avoids the need to define environment variables for
individual test targets to pass on SRC_PATH, but the fact that
we didn't rely on this before made me a bit apprehensive about
suggesting it. qemu-iotests for instance relies on a symlink
back to SRC_PATH, and check-qapi-schema tests feed individual
schema files to a script via tests/Makefile.include. Both can
be made to check against a different/changing SRC_PATH, but
if we bake it into the code that's not possible.

I'm not sure if there's a valid use-case for needing to do
so, but it seems to be bad form to not have any mechanism
to change them without recompiling. Personally I think I'd
prefer the environment variable approach, even if it means
needing to add it per-target. I think if we wanted to get
fancy we could do this via a recipe that exports environment
variables added to a lazily-evaluated Makefile variable by
each target's dependencies, but it's probably not worth it
outside of a more general cleanup to how we handle
SRC_PATH/BUILD_DIR dependencies throughout tests/

If others are fine with the approach taken here though I
wouldn't hold things up.

> ---
>  scripts/create_config | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/scripts/create_config b/scripts/create_config
> index 1dd6a35..2fbe126 100755
> --- a/scripts/create_config
> +++ b/scripts/create_config
> @@ -116,6 +116,9 @@ case $line in
>   DSOSUF=*)
>      echo "#define HOST_DSOSUF \"${line#*=}\""
>      ;;
> + SRC_PATH=*)
> +     echo "#define QEMU_SRC_PATH \"${line#*=}\""
> +     ;;
>  esac
> 
>  done # read
> -- 
> 2.7.4
>