From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9DA28C43331 for ; Tue, 31 Mar 2020 14:45:51 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6436B2078B for ; Tue, 31 Mar 2020 14:45:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="GjPR3ddV" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6436B2078B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:39260 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jJI9G-0007O3-GP for qemu-devel@archiver.kernel.org; Tue, 31 Mar 2020 10:45:50 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53421) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jJI8G-0006b9-1c for qemu-devel@nongnu.org; Tue, 31 Mar 2020 10:44:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jJI8E-0004jG-Oi for qemu-devel@nongnu.org; Tue, 31 Mar 2020 10:44:47 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:59382 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jJI8E-0004ix-Ko for qemu-devel@nongnu.org; Tue, 31 Mar 2020 10:44:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1585665886; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=lDTqBUMhaVKng5Y7OJaMsvUxUQJJFMv/g9IDIF1r5lg=; b=GjPR3ddVBlPtP4Ff7XwNdqsVi20UL0vy6Ff1QSApk0184qG4rWHdbBZSP+TIfnNXfeDe0Y w097k4QynuFiWkwoZj6djd4ISMAkssym1DfUhRtUuDpKNEkO5AiI4Z3trksnORzK2DUSvm 3K56CbrWTBCQeJ1P7u4cGupvktva62s= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-113-pCIVw1BRPV67QYmmAB347A-1; Tue, 31 Mar 2020 10:44:40 -0400 X-MC-Unique: pCIVw1BRPV67QYmmAB347A-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E4BD81005514; Tue, 31 Mar 2020 14:44:38 +0000 (UTC) Received: from [10.3.113.246] (ovpn-113-246.phx2.redhat.com [10.3.113.246]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0AA0598A29; Tue, 31 Mar 2020 14:44:37 +0000 (UTC) Subject: Re: [PATCH] configure: warn if not using a separate build directory To: =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= , qemu-devel@nongnu.org References: <20200331103758.370644-1-berrange@redhat.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: <042a22e2-5be5-ba57-1c35-8f210d9718fd@redhat.com> Date: Tue, 31 Mar 2020 09:44:37 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200331103758.370644-1-berrange@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Peter Maydell , Liviu Ionescu , Markus Armbruster , Stefan Hajnoczi , Paolo Bonzini , =?UTF-8?Q?Michal_Such=c3=a1nek?= , Aleksandar Markovic Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 3/31/20 5:37 AM, Daniel P. Berrang=C3=A9 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. >=20 > Signed-off-by: Daniel P. Berrang=C3=A9 > --- > configure | 30 ++++++++++++++++++++++++++++++ > 1 file changed, 30 insertions(+) >=20 It sounds like you already have a v2 coming up to address Phillipe's=20 comments, but I'd be happy to see this concept make it into v5.0. > 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 > # > =20 > +BUILDDIR=3D$(pwd) Why fork out to 'pwd', when we can rely on $PWD for the same answer?=20 Note that both $(pwd) and $PWD $BUILDDIR always give an absolute (but no=20 necessarily canonical) path, which means... > +SRCDIR=3D$(dirname "$0") > + > +ABS_BUILDDIR=3D$(realpath $BUILDDIR) ...calling this ABS_BUILDDIR is a misnomer (it was already absolute).=20 What it is really doing is chasing through symlinks to result in a=20 canonical name, particularly since unless you have absolute names, using=20 only string comparison to see if two filenames are equivalent will have=20 false negatives (/tmp vs. /tmp/., for example). > +ABS_SRCDIR=3D$(realpath $SRCDIR) Not robust if there are spaces in the directory names. Safer would be ABS_BUILDDIR=3D$(realpath -- "$BUILDDIR") and similarly for ABS_SRCDIR. > + > +in_srcdir=3Dno > +if [ "$ABS_SRCDIR" =3D=3D "$ABS_BUILDDIR" ] Bashism. You MUST spell this '=3D', not '=3D=3D', since configure is run un= der=20 /bin/sh which might be dash which does not understand =3D=3D. > +then > + in_srcdir=3Dyes > +fi > + > + > # Unset some variables known to interfere with behavior of common tools= , > # just as autoconf does. > CLICOLOR_FORCE=3D GREP_OPTIONS=3D > @@ -6799,6 +6812,23 @@ if test "$supported_os" =3D "no"; then > echo "us upstream at qemu-devel@nongnu.org." > fi > =20 > +if test "$in_srcdir" =3D "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 You know, it WOULD be possible to further enhance this to actually=20 create 'build' as well as a shim GNUmakefile that would auto-forward on=20 to building directly in build, so that you maintain the illusion of an=20 in-place build (other than all the build artifacts now living in a=20 different location), and muscle memory for in-tree 'make' still works;=20 I've posted elsewhere and will repeat here the contents of my GNUmakefile: # Hack for redirecting while reminding myself to use distinct builddir ifeq ($(MAKECMDGOALS),) recurse: all endif %: force =09@echo 'changing directory to build...' =09@sleep 2 =09@$(MAKE) -C build -f Makefile $(MAKECMDGOALS) force: ; .PHONY: force GNUmakefile: ; But we could do that as a patch on top of yours. --=20 Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org