From: Father Chrysostomos <sprout@cpan.org>
Date: Mon, 7 Dec 2009 13:58:40 +0000 (+0100)
Subject: [perl #71076] sort with active sub (5.10 regression)
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=8a27a13e89107aaf68c0748b68ee71fbd86d774b;p=p5sagit%2Fp5-mst-13.2.git

[perl #71076] sort with active sub (5.10 regression)

One of the tests in sort.t causes a bus error (or sometimes ‘Undefined
subroutine called’) if run multiple times. This is because sort
decreases the refcount of an active sub used as a comparison routine.

Ironically enough, this test was added by the very change that broke it
(25953/9850bf2).
---

diff --git a/pp_sort.c b/pp_sort.c
index a657fa7..12e77f9 100644
--- a/pp_sort.c
+++ b/pp_sort.c
@@ -1652,6 +1652,11 @@ PP(pp_sort)
 	    if (!(flags & OPf_SPECIAL)) {
 		cx->cx_type = CXt_SUB;
 		cx->blk_gimme = G_SCALAR;
+		/* If our comparison routine is already active (CvDEPTH is
+		 * is not 0),  then PUSHSUB does not increase the refcount,
+		 * so we have to do it ourselves, because the LEAVESUB fur-
+		 * ther down lowers it. */
+		if (CvDEPTH(cv)) SvREFCNT_inc_simple_void_NN(cv);
 		PUSHSUB(cx);
 		if (!is_xsub) {
 		    AV* const padlist = CvPADLIST(cv);
diff --git a/t/op/sort.t b/t/op/sort.t
index 75b9a17..24e1713 100644
--- a/t/op/sort.t
+++ b/t/op/sort.t
@@ -6,7 +6,7 @@ BEGIN {
     require 'test.pl';
 }
 use warnings;
-plan( tests => 147 );
+plan( tests => 148 );
 
 # these shouldn't hang
 {
@@ -701,8 +701,8 @@ $fail_msg = q(Can't undef active subroutine);
 cmp_ok(substr($@,0,length($fail_msg)),'eq',$fail_msg,'undef active subr');
 
 
-
-{
+for(1,2) # We run this twice, to make sure sort does not lower the ref
+{        # count. See bug 71076.
     my $failed = 0;
 
     sub rec {