From b3937e202aaf10c2f8996e2993c880bb38a7a268 Mon Sep 17 00:00:00 2001
From: Father Chrysostomos <sprout@cpan.org>
Date: Wed, 1 Nov 2017 13:11:27 -0700
Subject: [PATCH] =?UTF-8?q?Carp:=20Don=E2=80=99t=20choke=20on=20ISA=20cons?=
 =?UTF-8?q?tant?=
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This broke some time between 1.29 (perl 5.18) and 1.3301 (perl 5.20):

$ perl5.20.1 -e 'package Foo { use constant ISA => 42; Bar::f() } package Bar { use Carp; sub f { carp "tun syn" } }'
Not a GLOB reference at /usr/local/lib/perl5/5.20.1/Carp.pm line 560.

and still persisted in bleadperl (Carp 1.43) until this commit.

The code that goes poking through the symbol table needs to take into
account that not all stash elements are globs.

Signed-off-by: Petr Písař <ppisar@redhat.com>
---
 dist/Carp/lib/Carp.pm |  3 ++-
 dist/Carp/t/Carp.t    | 13 ++++++++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/dist/Carp/lib/Carp.pm b/dist/Carp/lib/Carp.pm
index 6127b26f54..ef11a0c046 100644
--- a/dist/Carp/lib/Carp.pm
+++ b/dist/Carp/lib/Carp.pm
@@ -593,7 +593,8 @@ sub trusts_directly {
     for my $var (qw/ CARP_NOT ISA /) {
         # Don't try using the variable until we know it exists,
         # to avoid polluting the caller's namespace.
-        if ( $stash->{$var} && *{$stash->{$var}}{ARRAY} && @{$stash->{$var}} ) {
+        if ( $stash->{$var} && ref \$stash->{$var} eq 'GLOB'
+          && *{$stash->{$var}}{ARRAY} && @{$stash->{$var}} ) {
            return @{$stash->{$var}}
         }
     }
diff --git a/dist/Carp/t/Carp.t b/dist/Carp/t/Carp.t
index 65daed7c6c..b1e399d143 100644
--- a/dist/Carp/t/Carp.t
+++ b/dist/Carp/t/Carp.t
@@ -3,7 +3,7 @@ no warnings "once";
 use Config;
 
 use IPC::Open3 1.0103 qw(open3);
-use Test::More tests => 67;
+use Test::More tests => 68;
 
 sub runperl {
     my(%args) = @_;
@@ -488,6 +488,17 @@ SKIP:
     );
 }
 
+{
+    package Mpar;
+    sub f { Carp::croak "tun syn" }
+
+    package Phou;
+    $Phou::{ISA} = \42;
+    eval { Mpar::f };
+}
+like $@, qr/tun syn/, 'Carp can handle non-glob ISA stash elems';
+
+
 # New tests go here
 
 # line 1 "XA"
-- 
2.13.6