Date: Fri, 25 Sep 1998 18:25:43 -0700 (PDT) From: bmah@ca.sandia.gov To: FreeBSD-gnats-submit@FreeBSD.ORG Subject: ports/8053: Perl 5 port has broken foreach behavior, possible fix Message-ID: <199809260125.SAA10576@eisenhower.ca.sandia.gov>
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>Number: 8053
>Category: ports
>Synopsis: Perl 5 port has broken foreach behavior, possible fix
>Confidential: no
>Severity: serious
>Priority: high
>Responsible: freebsd-ports
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Sep 25 18:30:00 PDT 1998
>Last-Modified:
>Originator: Bruce A. Mah
>Organization:
Sandia National Laboratories
>Release: FreeBSD 2.2.7-RELEASE i386
>Environment:
2.2.7-RELEASE, perl5 port cvsup'ed and compiled 23 September 1998
>Description:
Perl code that relies on the index variable in a foreach command may
get the wrong answer. This breaks vnc, and very likely other things
as well.
>How-To-Repeat:
Run the following perl script, which is an excerpt from vncserver(1):
-----8< snip 8<-----
#!/usr/local/bin/perl
$displayNumber = &GetDisplayNumber();
print "use display $displayNumber\n";
exit;
sub GetDisplayNumber
{
foreach $n (1..99) {
return $n;
}
}
-----8< snip 8<-----
The expected output is "use display 1". Our perl prints "use display ".
>Fix:
The following was forwarded from Jeff Mark <J.Mark@iname.com>,
via the vnc-list mailing list. Extremely cursory testing shows that it
seems to fix the problem.
From: "Gurusamy Sarathy" <gsar@engin.umich.edu>
To: <fmc@mugwump-prv.incyte.com>
Cc: <perlbug@perl.com>,
<hansm@icgroup.nl>,
"Jeff Mark" <J.Mark@dialogic.com>
Subject: Re: lexical gets freed too soon ?
Date: Fri, 18 Sep 1998 11:18:19 -0700
Message-ID: <199809181818.OAA09898@aatma.engin.umich.edu>
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In-Reply-To: Your message of "Thu, 17 Sep 1998 17:00:37 PDT." <199809180000.RAA21930@mugwump-prv.incyte.com>
On Thu, 17 Sep 1998 17:00:37 PDT, Frederic Chauveau wrote:
>Audit-Trail:
>Unformatted:
>The following snippet of code used to work in 5.003, is broken in
>both 5.005 and 5.005_51...
>
>It 'looks' like the temporary index for foreach gets free'd a bit too
soon...
>
>Is there's a patch (or something in the doc :) ?
Thanks to all the people that have reported the problem. Here's a patch.
I think a possibly more complicated fix is also possible if we fix
pp_return() to split the POPLOOP() like pp_leaveloop() and the others,
but I'll look into that later.
- Sarathy.
gsar@engin.umich.edu
-----------------------------------8<-----------------------------------
Change 1789 by gsar@aatma on 1998/09/18 18:01:37
delay freeing itervar so C<for $i (@a) { return($i) }> works
Affected files ...
... //depot/perl/cop.h#14 edit
... //depot/perl/t/cmd/for.t#6 edit
Differences ...
==== //depot/perl/cop.h#14 (text) ====
Index: perl/cop.h
--- perl/cop.h.~1~ Fri Sep 18 14:13:08 1998
+++ perl/cop.h Fri Sep 18 14:13:08 1998
@@ -143,7 +143,7 @@
#define POPLOOP2() \
SvREFCNT_dec(cxloop.iterlval); \
if (cxloop.itervar) { \
- SvREFCNT_dec(*cxloop.itervar); \
+ sv_2mortal(*cxloop.itervar); \
*cxloop.itervar = cxloop.itersave; \
} \
if (cxloop.iterary && cxloop.iterary != PL_curstack) \
==== //depot/perl/t/cmd/for.t#6 (xtext) ====
Index: perl/t/cmd/for.t
--- perl/t/cmd/for.t.~1~ Fri Sep 18 14:13:08 1998
+++ perl/t/cmd/for.t Fri Sep 18 14:13:08 1998
@@ -1,9 +1,7 @@
#!./perl
-# $RCSfile: for.t,v $$Revision: 4.1 $$Date: 92/08/07 18:27:09 $
-
-print "1..7\n";
+print "1..10\n";
for ($i = 0; $i <= 10; $i++) {
$x[$i] = $i;
}
@@ -46,4 +44,14 @@
foreach $foo (("ok 6\n","ok 7\n")) {
print $foo;
+}
+
+sub foo {
+ for $i (1..5) {
+ return $i if $_[0] == $i;
+ }
}
+
+print foo(1) == 1 ? "ok" : "not ok", " 8\n";
+print foo(2) == 2 ? "ok" : "not ok", " 9\n";
+print foo(5) == 5 ? "ok" : "not ok", " 10\n";
End of Patch.
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