ports/68147: [PATCH] bsd.port.mk: allow a port to conflict with itself

[Thomas-Martin Seck]

>Number:         68147
>Category:       ports
>Synopsis:       [PATCH] bsd.port.mk: allow a port to conflict with itself
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-ports-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          change-request
>Submitter-Id:   current-users
>Arrival-Date:   Sun Jun 20 15:20:16 GMT 2004
>Closed-Date:
>Last-Modified:
>Originator:     Thomas-Martin Seck
>Release:        FreeBSD 4.10-STABLE i386
>Organization:
a private site in Germany
>Environment:
FreeBSD ports collection as of June 20th, 2004.

	
>Description:
The ports system uses a conflicts checking mechanism to prevent a port
that is to be installed from overwriting an existing port's files. This
mechanism employs a variable CONFLICTS which is a list of basic regular
expressions which are used to check the list of installed ports that
were installed using the same PREFIX.

With the current checking algorithm it is not allowed for a port to
register a conflict with itself. This is eminent when a user wants to
force the reinstallation of an already installed port which had defined
a self-conflict (see below) by setting FORCE_PKG_REGISTER because then
the installation will be prevented with "PKGNAME conflicts with PKGNAME"
which is technically correct but not a problem that should prevent the
installation since the user explicitly wanted to overwrite the existing
installation.

So where do self-conflicts come from? Often there are multiple versions
of a popular software in the ports tree, depending on the release
policies of the upstream vendor. For the sake of example, imagine that
we have multiple versions of "myport" with package names of myport-1,
myport-2, and myport-3, maybe all maintained by different maintainers.
If the maintainer of myport-1 set CONFLICTS to myport-*, myport-1 would
correctly conflict with all further and previous versions of myport but
also with itself. So the maintainer of myport-1 needs to register a
conflict against myport-2, and myport-3. If myport-4 is added, he needs
to revisit his conflicts definition and add myport-4. The same applies
for the maintainers of myport-{2,3,...}. As long as the ports are
actively maintained this might work but I seriously doubt that a port
maintained by ports@ will ever be updated that way.

As the maintainer of the conflicting squid-2.4, squid-2.5, and the
upcoming squid-3.x ports I have been confronted with exactly this
problem when the conflicts check was introduced. My first conflicts
definition included a self-conflict and was thus criticized.

I propose that we allow a port to conflict with itself because the check
for a self-conflict is already covered by the check-already-installed
target which is run before the check-conflicts target. A self-conflict
should silently be discarded since the user expressed that he wants to
override the existing installation.

	
>How-To-Repeat:
Install these example ports (based upon an example presented by
eik@ on freebsd-ports) and force a reinstall.

# This is a shell archive.  Save it in a file, remove anything before
# this line, and then unpack it by entering "sh file".  Note, it may
# create directories; files and directories will be owned by you and
# have default permissions.
#
# This archive contains:
#
#	misc/conflicttest1/Makefile
#	misc/conflicttest1/pkg-descr
#	misc/conflicttest2/Makefile
#	misc/conflicttest2/pkg-descr
#
echo x - misc/conflicttest1/Makefile
sed 's/^X//' >misc/conflicttest1/Makefile << 'END-of-misc/conflicttest1/Makefile'
X# New ports collection makefile for:	conflicttest
X# Date created:				19 Jun 2004
X# Whom:					Thomas-Martin Seck
X#
X# $FreeBSD$
X#
X
XPORTNAME=	conflicttest
XPORTVERSION=	1.0
XCATEGORIES=	misc
XMASTER_SITES=	#
XDISTFILES=
X
XMAINTAINER=	tmseck at netcologne.de
XCOMMENT=	Version 1 of conflicttest
X
XCONFLICTS=	conflicttest-*
X
XLATEST_LINK=	conflicttest1
X
XNO_BUILD=	yes
X
Xdo-install:
X		@${ECHO_CMD} "===>   ${PKGNAME} sucessfully installed"
X
X.include <bsd.port.mk>
END-of-misc/conflicttest1/Makefile
echo x - misc/conflicttest1/pkg-descr
sed 's/^X//' >misc/conflicttest1/pkg-descr << 'END-of-misc/conflicttest1/pkg-descr'
X
END-of-misc/conflicttest1/pkg-descr
echo x - misc/conflicttest2/Makefile
sed 's/^X//' >misc/conflicttest2/Makefile << 'END-of-misc/conflicttest2/Makefile'
X# New ports collection makefile for:	conflicttest
X# Date created:				19 Jun 2004
X# Whom:					Thomas-Martin Seck
X#
X# $FreeBSD$
X#
X
XPORTNAME=	conflicttest
XPORTVERSION=	2.0
XCATEGORIES=	misc
XMASTER_SITES=	#
XDISTFILES=
X
XMAINTAINER=	tmseck at netcologne.de
XCOMMENT=	Version 2 of conflicttest
X
XCONFLICTS=	conflicttest-*
X
XLATEST_LINK=	conflicttest2
X
XNO_BUILD=	yes
X
Xdo-install:
X		@${ECHO_CMD} "===>   ${PKGNAME} sucessfully installed"
X
X.include <bsd.port.mk>
END-of-misc/conflicttest2/Makefile
echo x - misc/conflicttest2/pkg-descr
sed 's/^X//' >misc/conflicttest2/pkg-descr << 'END-of-misc/conflicttest2/pkg-descr'
X
END-of-misc/conflicttest2/pkg-descr
exit


	
>Fix:
Apply this patch to bsd.port.mk:

Index: bsd.port.mk
===================================================================
RCS file: /home/ncvs/ports/Mk/bsd.port.mk,v
retrieving revision 1.491
diff -u -u -r1.491 bsd.port.mk
--- bsd.port.mk	10 Jun 2004 07:30:19 -0000	1.491
+++ bsd.port.mk	20 Jun 2004 14:15:18 -0000
@@ -3093,7 +3093,7 @@
 		conflicting=0; \
 		for entry in $${found}; do \
 			prfx=`${PKG_INFO} -q -p $${entry} 2> /dev/null | ${SED} -ne '1s|^@cwd ||p'`; \
-			if [ "x${PREFIX}" = "x$${prfx}" ]; then \
+			if [ "x${PREFIX}" = "x$${prfx}" -a "x$${entry}" != "x${PKGNAME}" ]; then \
 				conflicting=1;\
 				conflicts_with="$${conflicts_with} $${entry}";\
 			fi;\
	


>Release-Note:
>Audit-Trail:
>Unformatted: