Re: [PATCH v4 for-5.0] configure: warn if not using a separate build directory

[Eric Blake <eblake@redhat.com>]

On 4/3/20 8:53 AM, Daniel P. Berrangé wrote:
> Running configure directly from the source directory is a build
> configuration that will go away in future. It is also not currently
> covered by any automated testing. Display a deprecation warning if
> the user attempts to use an in-srcdir build setup, so that they are
> aware that they're building QEMU in an undesirable manner.
> 
> Reviewed-by: Eric Blake <eblake@redhat.com>
> Reviewed-by: Markus Armbruster <armbru@redhat.com>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
> 
> Changed in v4:
>    - Adopted Eric's suggested wording

> +if test "$in_srcdir" = "yes"; then
> +    echo
> +    echo "WARNING: SUPPORT FOR BUILDING IN THE SOURCE DIR IS DEPRECATED"
> +    echo
> +    echo "Support for running the 'configure' script directly from the"
> +    echo "source directory is deprecated. In-tree builds are not covered"
> +    echo "by automated testing and thus may not correctly build QEMU."
> +    echo "Users are recommended to use a separate build directory:"
> +    echo
> +    echo "  $ mkdir build"
> +    echo "  $ cd build"
> +    echo "  $ ../configure"
> +    echo "  $ make"

Late question, but:

Since this is just a warning, we still manage to complete the 
./configure run, including whatever generated files it leaves in-tree. 
Is there any additional step we need to recommend prior to 'mkdir build' 
that will clean up the in-tree artifacts, so that the user then 
attempting the VPATH build won't still have a broken build due to the 
leftovers from the in-tree attempt?  'make distclean', perhaps?

/me starts testing; I'll reply back once it finishes...

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org