From: Dave Mitchell <davem@fdisolutions.com>
Date: Sun, 19 Jan 2003 16:43:54 +0000 (+0000)
Subject: Re: [perl #15439] unreferenced scalar due to double DESTROY
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=6b42d12b8135b62734b087ee4b02cf28d259a483;p=p5sagit%2Fp5-mst-13.2.git

Re: [perl #15439] unreferenced scalar due to double DESTROY
Message-ID: <20030119164353.B24444@fdgroup.com>

p4raw-id: //depot/perl@18554
---

diff --git a/av.c b/av.c
index acc9963..10cc2fe 100644
--- a/av.c
+++ b/av.c
@@ -453,8 +453,11 @@ Perl_av_clear(pTHX_ register AV *av)
 	ary = AvARRAY(av);
 	key = AvFILLp(av) + 1;
 	while (key) {
-	    SvREFCNT_dec(ary[--key]);
+	    SV * sv = ary[--key];
+	    /* undef the slot before freeing the value, because a
+	     * destructor might try to modify this arrray */
 	    ary[key] = &PL_sv_undef;
+	    SvREFCNT_dec(sv);
 	}
     }
     if ((key = AvARRAY(av) - AvALLOC(av))) {
diff --git a/t/op/array.t b/t/op/array.t
index 472e02c..8f2f1a9 100755
--- a/t/op/array.t
+++ b/t/op/array.t
@@ -1,6 +1,12 @@
 #!./perl
 
-print "1..72\n";
+
+BEGIN {
+    chdir 't' if -d 't';
+    @INC = '../lib';
+}
+
+print "1..73\n";
 
 #
 # @foo, @bar, and @ary are also used from tie-stdarray after tie-ing them
@@ -247,3 +253,22 @@ sub tary {
 
 @tary = (0..50);
 tary();
+
+
+require './test.pl';
+
+# bugid #15439 - clearing an array calls destructors which may try
+# to modify the array - caused 'Attempt to free unreferenced scalar'
+
+my $got = runperl (
+	prog => q{
+		    sub X::DESTROY { @a = () }
+		    @a = (bless {}, 'X');
+		    @a = ();
+		},
+	stderr => 1
+    );
+
+$got =~ s/\n/ /g;
+print "# $got\nnot " unless $got eq '';
+print "ok 73\n";