Carp inadvertently autovivifies CORE::GLOBAL::caller

[p5pRT]

Migrated from rt.perl.org#78082 (status was 'resolved')

Searchable as RT78082$

[p5pRT]

From @arc

Created by @arc

As of bf236c8, lib/Carp.pm contains a bare
reference to \&CORE​::GLOBAL​::caller. This autovivifies
$CORE​::GLOBAL​::{caller}, which could be annoying in some situations.

The attached patch fixes that, and adds a test to prevent it happening again.

Perl Info

Flags:
    category=library
    severity=low
    module=Carp

Site configuration information for perl 5.13.5:

Configured by aaron at Fri Sep 24 09:48:49 BST 2010.

Summary of my perl5 (revision 5 version 13 subversion 5) configuration:
  Commit id: 6481ebaf76d95c32fd79e91c0f39c17b16bd73e4
  Platform:
    osname=darwin, osvers=10.4.0, archname=darwin-2level
    uname='darwin zzz 10.4.0 darwin kernel version 10.4.0: fri apr 23
18:28:53 pdt 2010; r
    config_args='-des -Dprefix=/opt/bleadperl -Dusedevel'
    hint=recommended, useposix=true, d_sigaction=define
    useithreads=undef, usemultiplicity=undef
    useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
    use64bitint=define, use64bitall=define, uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-fno-common -DPERL_DARWIN -no-cpp-precomp
-fno-strict-aliasing -pip
    optimize='-O3',
    cppflags='-no-cpp-precomp -fno-common -DPERL_DARWIN
-no-cpp-precomp -fno-strict-aliasi
    ccversion='', gccversion='4.2.1 (Apple Inc. build 5664)', gccosandvers=''
    intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
    ivtype='long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t',
lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='env MACOSX_DEPLOYMENT_TARGET=10.3 cc', ldflags ='
-fstack-protector -L/opt/local/l
    libpth=/opt/local/lib /usr/lib
    libs=-lgdbm -ldbm -ldl -lm -lutil -lc
    perllibs=-ldl -lm -lutil -lc
    libc=/usr/lib/libc.dylib, so=dylib, useshrplib=false, libperl=libperl.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=bundle, d_dlsymun=undef, ccdlflags=' '
    cccdlflags=' ', lddlflags=' -bundle -undefined dynamic_lookup
-L/opt/local/lib -fstack

Locally applied patches:



@INC for perl 5.13.5:
    /opt/bleadperl/lib/site_perl/5.13.5/darwin-2level
    /opt/bleadperl/lib/site_perl/5.13.5
    /opt/bleadperl/lib/5.13.5/darwin-2level
    /opt/bleadperl/lib/5.13.5
    /opt/bleadperl/lib/site_perl
    .


Environment for perl 5.13.5:
    DYLD_LIBRARY_PATH (unset)
    HOME=/Users/zzz
    LANG=en_GB.UTF-8
    LANGUAGE (unset)
    LC_COLLATE=C
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/X11/bin
    PERL_BADLANG (unset)
    SHELL=/bin/bash

-- 
Aaron Crane ** http://aaroncrane.co.uk/

[p5pRT]

From @arc

0001-lib-Carp.pm-Avoid-autovivification-of-CORE-GLOBAL-ca.patch

From 93553813cde1bf59b3422a33435f467cc3c23dfb Mon Sep 17 00:00:00 2001
From: Aaron Crane <arc@cpan.org>
Date: Mon, 27 Sep 2010 12:02:01 +0100
Subject: [PATCH] lib/Carp.pm: Avoid autovivification of CORE::GLOBAL::caller

And add a test to prevent this happening again.
---
 lib/Carp.pm |    3 ++-
 lib/Carp.t  |    9 +++++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/lib/Carp.pm b/lib/Carp.pm
index 0e9105a..6aba427 100644
--- a/lib/Carp.pm
+++ b/lib/Carp.pm
@@ -86,7 +86,8 @@ sub caller_info {
       @DB::args = (); # Don't let anyone see the address of $i
       local $@;
       my $where = eval {
-	my $gv = B::svref_2object(\&CORE::GLOBAL::caller)->GV;
+	my $func = defined &{"CORE::GLOBAL::caller"} ? \&{"CORE::GLOBAL::caller"} : return '';
+	my $gv = B::svref_2object($func)->GV;
 	my $package = $gv->STASH->NAME;
 	my $subname = $gv->NAME;
 	return unless defined $package && defined $subname;
diff --git a/lib/Carp.t b/lib/Carp.t
index 1c59987..8240cd3 100644
--- a/lib/Carp.t
+++ b/lib/Carp.t
@@ -11,9 +11,14 @@ my $Is_VMS = $^O eq 'VMS';
 
 use Carp qw(carp cluck croak confess);
 
-plan tests => 56;
+BEGIN {
+	plan tests => 56;
 
-ok 1;
+	# This test must be run at BEGIN time, because code later in this file
+	# sets CORE::GLOBAL::caller
+	ok !exists $CORE::GLOBAL::{caller},
+	  "Loading doesn't create CORE::GLOBAL::caller"
+}
 
 { local $SIG{__WARN__} = sub {
     like $_[0], qr/ok (\d+)\n at.+\b(?i:carp\.t) line \d+$/, 'ok 2\n' };
-- 
1.7.3

[p5pRT]

From @cpansprout

On Mon Sep 27 04​:19​:47 2010, arc wrote​:

As of bf236c8, lib/Carp.pm contains a
bare
reference to \&CORE​::GLOBAL​::caller. This autovivifies
$CORE​::GLOBAL​::{caller}, which could be annoying in some situations.

The attached patch fixes that, and adds a test to prevent it happening
again.

Thank you. I’ve applied this as 39d0b21ca5a59dba7652555c425faec6c7a5e653.

[p5pRT]

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

[p5pRT]

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