Integrate change #9108 from maintperl to mainline.

fix memory leak in C<sub X { sub {} }> arising from a refcount
loop between the outer sub and the inner prototype anonsub

this also enables closures returned by subroutines that
subsequently get redefined to work without generating coredumps :)

completely removed the free_closures() hack--it shouldn't be
needed anymore

p4raw-link: @9108 on //depot/maint-5.6/perl: 1cf1f64f42eb50a67f2427ff9d6d24023a2b9997

p4raw-id: //depot/perl@9109
p4raw-branched: from //depot/maint-5.6/perl@9107 'branch in'
	t/op/anonsub.t
p4raw-integrated: from //depot/maint-5.6/perl@9107 'merge in' sv.c
	(@8871..) embed.h (@8886..) pod/perlapi.pod proto.h (@8993..)
	embed.pl (@8995..) MANIFEST (@9030..) op.c op.h (@9055..)
	pp_ctl.c (@9076..)

1 files changed, 93 insertions, 0 deletions

diff --git a/t/op/anonsub.t b/t/op/anonsub.t
new file mode 100755
index 0000000000..17889d9d2f
--- /dev/null
+++ b/t/op/anonsub.t
@@ -0,0 +1,93 @@
+#!./perl
+
+chdir 't' if -d 't';
+@INC = '../lib';
+$Is_VMS = $^O eq 'VMS';
+$Is_MSWin32 = $^O eq 'MSWin32';
+$ENV{PERL5LIB} = "../lib" unless $Is_VMS;
+
+$|=1;
+
+undef $/;
+@prgs = split "\n########\n", <DATA>;
+print "1..", scalar @prgs, "\n";
+
+$tmpfile = "asubtmp000";
+1 while -f ++$tmpfile;
+END { if ($tmpfile) { 1 while unlink $tmpfile; } }
+
+for (@prgs){
+    my $switch = "";
+    if (s/^\s*(-\w+)//){
+       $switch = $1;
+    }
+    my($prog,$expected) = split(/\nEXPECT\n/, $_);
+    open TEST, ">$tmpfile";
+    print TEST "$prog\n";
+    close TEST;
+    my $results = $Is_VMS ?
+                  `MCR $^X "-I[-.lib]" $switch $tmpfile 2>&1` :
+		      $Is_MSWin32 ?  
+			  `.\\perl -I../lib $switch $tmpfile 2>&1` :
+			      `./perl $switch $tmpfile 2>&1`;
+    my $status = $?;
+    $results =~ s/\n+$//;
+    # allow expected output to be written as if $prog is on STDIN
+    $results =~ s/runltmp\d+/-/g;
+    $results =~ s/\n%[A-Z]+-[SIWEF]-.*$// if $Is_VMS;  # clip off DCL status msg
+    $expected =~ s/\n+$//;
+    if ($results ne $expected) {
+       print STDERR "PROG: $switch\n$prog\n";
+       print STDERR "EXPECTED:\n$expected\n";
+       print STDERR "GOT:\n$results\n";
+       print "not ";
+    }
+    print "ok ", ++$i, "\n";
+}
+
+__END__
+sub X {
+    my $n = "ok 1\n";
+    sub { print $n };
+}
+my $x = X();
+undef &X;
+$x->();
+EXPECT
+ok 1
+########
+sub X {
+    my $n = "ok 1\n";
+    sub {
+        my $dummy = $n;	# eval can't close on $n without internal reference
+	eval 'print $n';
+	die $@ if $@;
+    };
+}
+my $x = X();
+undef &X;
+$x->();
+EXPECT
+ok 1
+########
+sub X {
+    my $n = "ok 1\n";
+    eval 'sub { print $n }';
+}
+my $x = X();
+die $@ if $@;
+undef &X;
+$x->();
+EXPECT
+ok 1
+########
+sub X;
+sub X {
+    my $n = "ok 1\n";
+    eval 'sub Y { my $p = shift; $p->() }';
+    die $@ if $@;
+    Y(sub { print $n });
+}
+X();
+EXPECT
+ok 1