From owner-freebsd-bugs  Fri Jan 18  7: 0:15 2002
Delivered-To: freebsd-bugs@hub.freebsd.org
Received: from freefall.freebsd.org (freefall.FreeBSD.org [216.136.204.21])
	by hub.freebsd.org (Postfix) with ESMTP id 09EA337B41C
	for <freebsd-bugs@hub.freebsd.org>; Fri, 18 Jan 2002 07:00:02 -0800 (PST)
Received: (from gnats@localhost)
	by freefall.freebsd.org (8.11.6/8.11.6) id g0IF01P31076;
	Fri, 18 Jan 2002 07:00:01 -0800 (PST)
	(envelope-from gnats)
Received: from wwweasel.geeksrus.net (wwweasel.geeksrus.net [64.67.200.82])
	by hub.freebsd.org (Postfix) with ESMTP
	id 239E837B419; Fri, 18 Jan 2002 06:57:12 -0800 (PST)
Received: (from alane@localhost)
	by wwweasel.geeksrus.net (8.11.6/8.11.6) id g0IEuhC39935;
	Fri, 18 Jan 2002 09:56:43 -0500 (EST)
	(envelope-from alane)
Message-Id: <200201181456.g0IEuhC39935@wwweasel.geeksrus.net>
Date: Fri, 18 Jan 2002 09:56:43 -0500 (EST)
From: Alan Eldridge <ports@geeksrus.net>
Reply-To: Alan Eldridge <ports@geeksrus.net>
To: FreeBSD-gnats-submit@freebsd.org
Cc: sobomax@freebsd.org
X-Send-Pr-Version: 3.113
Subject: bin/34032: make fails to evaluate some reasonable conditional expressions 
Sender: owner-freebsd-bugs@FreeBSD.ORG
Precedence: bulk
List-ID: <freebsd-bugs.FreeBSD.ORG>
List-Archive: <http://docs.freebsd.org/mail/> (Web Archive)
List-Help: <mailto:majordomo@FreeBSD.ORG?subject=help> (List Instructions)
List-Subscribe: <mailto:majordomo@FreeBSD.ORG?subject=subscribe%20freebsd-bugs>
List-Unsubscribe: <mailto:majordomo@FreeBSD.ORG?subject=unsubscribe%20freebsd-bugs>
X-Loop: FreeBSD.org


>Number:         34032
>Category:       bin
>Synopsis:       make fails to evaluate some reasonable conditional expressions
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Jan 18 07:00:01 PST 2002
>Closed-Date:
>Last-Modified:
>Originator:     Alan Eldridge
>Release:        FreeBSD 4.4-STABLE i386
>Organization:
Geeksrus.NET
>Environment:
System: FreeBSD wwweasel.geeksrus.net 4.4-STABLE FreeBSD 4.4-STABLE #0: Sun Dec 2 19:14:12 EST 2001 root@wwweasel.geeksrus.net:/usr/obj/usr/src/sys/WWWEASEL i386

>Description:

A conditional such as:

.if defined(WITH_FOO) && ${WITH_FOO:L} == yes

does not evaluate correctly if WITH_FOO is undefined.

This is exactly the sort of test we should be doing in ports makefiles
to check for settings of knobs which control the build.  Make shouldn't 
choke on this.

Note: 

.if defined(WITH_FOO) && ${WITH_FOO} == yes

works ok. It's the :L operator that is not behaving in the case of the
variable being undefined.

>How-To-Repeat:
[alane ~]$ cat Makefile

.if defined(WITH_FOO) && ${WITH_FOO:L} == yes
all:
        echo foo
.else
all:
        echo bar
.endif
[alane ~]$ make all
"Makefile", line 1: Malformed conditional (defined(WITH_FOO) && ${WITH_FOO:L} == yes)
"Makefile", line 1: Need an operator
"Makefile", line 4: if-less else
"Makefile", line 4: Need an operator
"Makefile", line 7: if-less endif
"Makefile", line 7: Need an operator
make: fatal errors encountered -- cannot continue
[alane ~]$ make WITH_FOO=XX all
echo bar
bar
[alane ~]$ make WITH_FOO=YES all
echo foo
foo
[alane ~]$

>Fix:

First, we have to decide what is broken. 

1. The evaluation should be short-circuited once the value is known.

OR

2. The :L and :U (and generally, all the :X suffix) operators should
   apply to an undefined variable as if it was defined to "".

Which one is right? I think (1) is right; (2) introduces "silent
failure" cases where error diagnostics should be produced.




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

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-bugs" in the body of the message