From a1d407e84f3b3d7067df3576c788e85a4b4857e5 Mon Sep 17 00:00:00 2001
From: Dave Mitchell <davem@fdisolutions.com>
Date: Thu, 17 Jul 2003 22:51:12 +0100
Subject: [ PATCH] Re: isa(UNIVERSAL)? Message-ID:
 <20030717205112.GA2994@fdgroup.com>

p4raw-id: //depot/perl@20168
---
 t/op/universal.t | 10 +++++++++-
 universal.c      |  6 ++++--
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/t/op/universal.t b/t/op/universal.t
index 7d5f59ae6d..71daf675cf 100755
--- a/t/op/universal.t
+++ b/t/op/universal.t
@@ -9,7 +9,7 @@ BEGIN {
     $| = 1;
 }
 
-print "1..98\n";
+print "1..100\n";
 
 $a = {};
 bless $a, "Bob";
@@ -187,3 +187,11 @@ test ! UNIVERSAL::isa("\xff\xff\xff\0", 'HASH');
     ::test $x->isa("Human");
     ::test $x->can("eat");
 }
+
+# bugid 3284
+# a second call to isa('UNIVERSAL') when @ISA is null failed due to caching
+
+@X::ISA=();
+my $x = {}; bless $x, 'X';
+test $x->isa('UNIVERSAL');
+test $x->isa('UNIVERSAL');
diff --git a/universal.c b/universal.c
index b4563e41a8..9ee3e21a73 100644
--- a/universal.c
+++ b/universal.c
@@ -45,6 +45,9 @@ S_isa_lookup(pTHX_ HV *stash, const char *name, HV* name_stash,
     if (strEQ(HvNAME(stash), name))
 	return &PL_sv_yes;
 
+    if (strEQ(name, "UNIVERSAL"))
+	return &PL_sv_yes;
+
     if (level > 100)
 	Perl_croak(aTHX_ "Recursive inheritance detected in package '%s'",
 		   HvNAME(stash));
@@ -112,8 +115,7 @@ S_isa_lookup(pTHX_ HV *stash, const char *name, HV* name_stash,
 	    (void)hv_store(hv,name,len,&PL_sv_no,0);
 	}
     }
-
-    return boolSV(strEQ(name, "UNIVERSAL"));
+    return &PL_sv_no;
 }
 
 /*
-- 
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