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

[Philippe Mathieu-Daudé]

On 3/31/20 1:41 PM, Daniel P. Berrangé wrote:
> 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 <address@hidden>
> > > ---
> > >    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 address@hidden."
> > >    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.

IMO we should move them to the end too.

I'm getting this output:

$ ./configure
[...]
plugin support    no
fuzzing support   no
gdb               /usr/bin/gdb

WARNING: SUPPORT FOR IN SOURCE DIR BUILDS IS DEPRECATED

Support for running the 'configure' script directly from the
source directory is deprecated and will go away in a future
release. In source dir builds are not covered by automated
testing and are liable to break without warning. Users are
strongly recommended to switch to a separate build directory:

  $ mkdir build
  $ cd build
  $ ../configure
  $ make

cross containers  docker

NOTE: guest cross-compilers enabled: cc cc
$

We might also move the cross-x messages earlier.
Anyway all my comments can be postponed to 5.1, so if other agree with 
your patch, let's KISS for 5.1-rc1.

> > Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
> > Tested-by: Philippe Mathieu-Daudé <address@hidden>
> >
> > > +
> > >    config_host_mak="config-host.mak"
> > >    echo "# Automatically generated by configure - do not modify" 
> > > >config-all-disas.mak
>
> Regards,
> Daniel