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

["Daniel P. Berrangé" <berrange@redhat.com>]

On Tue, Mar 31, 2020 at 01:11:45PM +0200, Philippe Mathieu-Daudé wrote:
> 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.

Sure, could do that..

> 
> > +
> > +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.

You can't see it from the diff, but immediately before here are a bunch
of other big warnings for users, so I figured it was a good idea to keep
them all together.

> 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
> > 
> 

Regards,
Daniel
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