Bug in Term::Complete Module with $_ Usage #7616

p5pRT · 2004-11-26T15:58:54Z

Migrated from rt.perl.org#32639 (status was 'resolved')

Searchable as RT32639$

p5pRT · 2004-11-26T15:58:55Z

From adalbert.perbandt@infineon.com

Created by adalbert.perbandt@infineon.com

The sub "Complete" in the file "Complete.pm" assigns data
to the $_ variable without having done a "local $_;" in
advance. This way it produces a side effect at the
caller.

Perl Info


Flags:
    category=core
    severity=medium

This perlbug was built using Perl v5.8.5 - Fri Jul 30 15:38:45 MEST 2004
It is being executed now by  Perl v5.8.5 - Fri Jul 30 08:29:00 MEST 2004.

Site configuration information for perl v5.8.5:

Configured by hwadm at Fri Jul 30 08:29:00 MEST 2004.

Summary of my perl5 (revision 5 version 8 subversion 5) configuration:
  Platform:
    osname=solaris, osvers=2.8, archname=sun4-solaris-thread-multi
    uname='sunos oslo05 5.8 generic_117350-02 sun4us sparc fjsv,gpuzc-m '
    config_args='-Dprefix=/opt/perl_5.8.5 -Dmydomain=.muc.infineon.com -Dcf_email=perl@muc.infineon.com -Dinstallusrbinperl=undef -Dperl5=/opt/perl_5.8.5/bin/perl -Dsitebin=/opt/perl_5.8.5/bin -Dman1dir=/opt/perl_5.8.5/share/man/man1 -Dman3dir=/opt/perl_5.8.5/share/man/man3 -Dperladmin=perl@muc.infineon.com -Dprivlib=/opt/perl_5.8.5/share/lib -Dscriptdir=/opt/perl_5.8.5/share/bin -Dsitescript=/opt/perl_5.8.5/share/bin -Dsitelib=/opt/perl_5.8.5/share/lib -Ubincompat5005 -Dlibperl=libperlifx.so -Dcc=gcc -Doptimize=-O2 -Dldflags=-static-libgcc -Dlddlflags=-G -static-libgcc -Darchlib=/opt/perl_5.8.5/lib/sun4-solaris-thread-multi -Dsitearch=/opt/perl_5.8.5/lib/sun4-solaris-thread-multi -Dlocincpth=/home/hwadm/TWW/SOL/include -Dloclibpth=/home/hwadm/TWW/SOL/lib -Dglibpth=/usr/lib -Duseshrplib -Dusethreads -Dpager=/usr/local/bin/less -des'
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=define use5005threads=undef useithreads=define usemultiplicity=define
    useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
    use64bitint=undef use64bitall=undef uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='gcc', ccflags ='-D_REENTRANT -fno-strict-aliasing -pipe -I/home/hwadm/TWW/SOL/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
    optimize='-O2',
    cppflags='-D_REENTRANT -fno-strict-aliasing -pipe -I/home/hwadm/TWW/SOL/include'
    ccversion='', gccversion='3.2.3', gccosandvers='solaris2.8'
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=4321
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='gcc', ldflags ='-static-libgcc -L/home/hwadm/TWW/SOL/lib '
    libpth=/home/hwadm/TWW/SOL/lib /usr/lib
    libs=-lsocket -lnsl -lgdbm -ldb -ldl -lm -lpthread
    perllibs=-lsocket -lnsl -ldl -lm -lpthread
    libc=/lib/libc.so, so=so, useshrplib=true, libperl=libperlifx.so
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='  -R /opt/perl_5.8.5/lib/sun4-solaris-thread-multi/CORE'
    cccdlflags='-fPIC', lddlflags='-G -static-libgcc -L/home/hwadm/TWW/SOL/lib'

Locally applied patches:
    


@INC for perl v5.8.5:
    /opt/perl_5.8.5/lib/sun4-solaris-thread-multi
    /opt/perl_5.8.5/share/lib
    /opt/perl_5.8.5/lib/sun4-solaris-thread-multi
    /opt/perl_5.8.5/share/lib
    /opt/perl_5.8.5/share/lib
    .


Environment for perl v5.8.5:
    HOME=/home/perbandt
    LANG=en_US
    LANGUAGE (unset)
    LD_LIBRARY_PATH=/usr/dt/lib:/usr/lib
    LOGDIR (unset)
    PATH=/opt/perl_5.8.5/bin:/var/vob/relman/admin/vob/devenv/bin:/usr/atria/bin:/opt/OpenOffice_1.1.3/program:/usr/dt/bin:/usr/bin:.:/usr/openwin/bin:/bin:/home/hwadm/bin:/home/bondtool/bin:.:/home/perbandt/bin:/usr/sbin:/home/relman/bin:/opt/ica_7.21:/opt/TWWfsw/bin:/usr/local/bin:/usr/ucb
    PERL_BADLANG (unset)
    SHELL=/bin/tcsh

p5pRT · 2004-11-26T16:57:11Z

From @smpeters

Do you have an example that may demonstrate this problem? It would be
helpful for testing and fixing the problem.

Thanks!

p5pRT · 2004-11-26T16:57:13Z

The RT System itself - Status changed from 'new' to 'open'

p5pRT · 2004-11-26T17:14:32Z

From @smpeters

Actually, the bug can be demonstrated with the following script:

#!/usr/bin/perl -w

use strict;
use lib ".";
use Term::Complete;

$_ = "Foo";
my @completion_list;
my $input = Complete('Hit Enter', \@completion_list);

print "$_\n";

Now, here's the patch that fixes the problem.

Inline Patch

--- /usr/libdata/perl5/Term/Complete.pm Fri Sep 17 13:09:30 2004
+++ ./Term/Complete.pm  Fri Nov 26 11:13:08 2004
@@ -5,7 +5,7 @@
 use strict;
 our @ISA = qw(Exporter);
 our @EXPORT = qw(Complete);
-our $VERSION = '1.401';
+our $VERSION = '1.402';

 #      @(#)complete.pl,v1.2            (me@anywhere.EBay.Sun.COM) 09/23/91

@@ -113,6 +113,7 @@
     }
     system $tty_raw_noecho if defined $tty_raw_noecho;
     LOOP: {
+        local $_;
         print($prompt, $return);
         while (($_ = getc(STDIN)) ne "\r") {
             CASE: {

p5pRT · 2004-11-26T17:53:16Z

From @rgs

Steve Peters via RT wrote:

Now, here's the patch that fixes the problem.

Thanks, applied as #23548 to bleadperl.

--- /usr/libdata/perl5/Term/Complete.pm Fri Sep 17 13:09:30 2004
+++ ./Term/Complete.pm Fri Nov 26 11:13:08 2004

p5pRT · 2004-11-26T21:15:54Z

From adalbert.perbandt@infineon.com

"Steve" == Steve Peters via <RT" <perlbug-followup@perl.org>> writes:

Steve> Do you have an example that may demonstrate this problem?
Steve> It would be helpful for testing and fixing the problem.

I didn't spend the effort to generate a minimal example but I think
the information given below should help:

1. This is a code snippet from inside a script:

[...]
use Class::Autouse qw(
IFXClearCase::Project
IFXClearCase::Component
IFXClearCase::Baseline
IFXClearCase::EnvHandler
IFXClearCase::ProjectManager
IFXClearCase::WorkspaceManager
);

my $env = IFXClearCase::EnvHandler->instance();
my $projMgr = IFXClearCase::ProjectManager->new(ENVHANDLER => $env);
my $project = IFXClearCase::Project->lookup(NAME => "InwayDev-5.0",
PVOB => $env->getPVOBTag());

my $devenv =
IFXClearCase::Component->lookup(NAME =>"devenv@/var/vob/relman/p/vob");

my @roComps = ($devenv);

my %roCompBls;
foreach (@roComps) {
print("\n\$\_: `$_'\n");
my $bl = $_->prompt4Baseline();
print("\n\$\_: `$_'\n");
if (!defined $bl) {
print("BLOED!\n");
exit(1);
}
$roCompBls{$_} = $bl;
}
[...]

See the foreach loop. I have inserted print() statements immediately
before and after the call of the prompt4Baseline() method. In this
method I have isolated the location where the $_ variable gets
overwritten. It's in this code snippet:

sub prompt4Baseline
{
[...]
print("\nprompt4Baseline: \$\_: `$_'\n");
my $blName;
if (-t STDIN) {
$blName = Complete("Choose one: ", @baselineIds);
} else {
$blName = <STDIN>;
chomp $blName;
}
$blName =~ s/^\s+|\s+$//g; # Remove leading and trailing whitespace.
print("\nprompt4Baseline: \$\_: `$_'\n");

We then inspected the source code of the Complete.pm. In the code of
the sub Complete we found this:

[...]
LOOP: {
print($prompt, $return);
while (($_ = getc(STDIN)) ne "\r") {
[...]

In the while statements condition part $_ gets overwritten. We did not
find a place before this location where $_ would have been made local.

Regards,

Adalbert.

p5pRT · 2004-11-26T21:58:32Z

From adalbert.perbandt@infineon.com

"Steve" == Steve Peters via <RT" <perlbug-followup@perl.org>> writes:

Steve> Actually, the bug can be demonstrated with the following
Steve> script:

Thanks a lot.

Regards

Adalbert.

p5pRT · 2004-11-28T05:11:25Z

From @ysth

On Fri, Nov 26, 2004 at 05:14:33PM -0000, Steve Peters wrote:

--- /usr/libdata/perl5/Term/Complete.pm Fri Sep 17 13:09:30 2004
+++ ./Term/Complete.pm Fri Nov 26 11:13:08 2004
@@ -5,7 +5,7 @@
use strict;
our @ISA = qw(Exporter);
our @EXPORT = qw(Complete);
-our $VERSION = '1.401';
+our $VERSION = '1.402';

# @(#)complete.pl,v1.2 (me@anywhere.EBay.Sun.COM) 09/23/91

@@ -113,6 +113,7 @@
}
system $tty_raw_noecho if defined $tty_raw_noecho;
LOOP: {
+ local $_;
print($prompt, $return);
while (($_ = getc(STDIN)) ne "\r") {
CASE: {

I thought the preferred way to do this was "local *_;" in maint or
"my $_;" in blead. Or, better yet, use a lexical $char instead of $_
throughout the block.

p5pRT · 2004-12-09T19:17:03Z

@rgs - Status changed from 'open' to 'resolved'

p5pRT closed this as completed Dec 9, 2004

p5pRT added Severity Medium distro-Solaris type-core labels Oct 18, 2019

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Bug in Term::Complete Module with $_ Usage #7616

Bug in Term::Complete Module with $_ Usage #7616

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p5pRT commented Dec 9, 2004

Bug in Term::Complete Module with $_ Usage #7616

Bug in Term::Complete Module with $_ Usage #7616

Comments

p5pRT commented Nov 26, 2004

p5pRT commented Nov 26, 2004

From adalbert.perbandt@infineon.com

Created by adalbert.perbandt@infineon.com

p5pRT commented Nov 26, 2004

From @smpeters

p5pRT commented Nov 26, 2004

p5pRT commented Nov 26, 2004

From @smpeters

p5pRT commented Nov 26, 2004

From @rgs

p5pRT commented Nov 26, 2004

From adalbert.perbandt@infineon.com

p5pRT commented Nov 26, 2004

From adalbert.perbandt@infineon.com

p5pRT commented Nov 28, 2004

From @ysth

p5pRT commented Dec 9, 2004