Re: [PATCH] configure: warn if not using a separate build directory

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 3/31/20 12:37 PM, 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.
> 
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
>   configure | 30 ++++++++++++++++++++++++++++++
>   1 file changed, 30 insertions(+)
> 
> diff --git a/configure b/configure
> index e225a1e3ff..1ab7492ab5 100755
> --- a/configure
> +++ b/configure
> @@ -3,6 +3,19 @@
>   # qemu configure script (c) 2003 Fabrice Bellard
>   #
>   
> +BUILDDIR=$(pwd)
> +SRCDIR=$(dirname "$0")

This duplicates $source_path.
Maybe you can rename it $source_path and remove the $source_path 
assignment later.

> +
> +ABS_BUILDDIR=$(realpath $BUILDDIR)
> +ABS_SRCDIR=$(realpath $SRCDIR)
> +
> +in_srcdir=no
> +if [ "$ABS_SRCDIR" == "$ABS_BUILDDIR" ]
> +then
> +    in_srcdir=yes
> +fi
> +
> +
>   # Unset some variables known to interfere with behavior of common tools,
>   # just as autoconf does.
>   CLICOLOR_FORCE= GREP_OPTIONS=
> @@ -6799,6 +6812,23 @@ if test "$supported_os" = "no"; then
>       echo "us upstream at qemu-devel@nongnu.org."
>   fi
>   
> +if test "$in_srcdir" = "yes"; then
> +    echo
> +    echo "WARNING: SUPPORT FOR IN SOURCE DIR BUILDS IS DEPRECATED"
> +    echo
> +    echo "Support for running the 'configure' script directly from the"
> +    echo "source directory is deprecated and will go away in a future"
> +    echo "release. In source dir builds are not covered by automated"
> +    echo "testing and are liable to break without warning. Users are"
> +    echo "strongly recommended to switch to a separate build directory:"
> +    echo
> +    echo "  $ mkdir build"
> +    echo "  $ cd build"
> +    echo "  $ ../configure"
> +    echo "  $ make"
> +    echo
> +fi

I'd move it at the very end of the file, to be the last thing displayed.

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> +
>   config_host_mak="config-host.mak"
>   
>   echo "# Automatically generated by configure - do not modify" >config-all-disas.mak
>