make join.t threadsafe!

tests 13 and 14 could output in reverse order. Add a lock to stop
this.

p4raw-id: //depot/perl@24455

1 files changed, 3 insertions, 0 deletions

diff --git a/ext/threads/t/join.t b/ext/threads/t/join.t
index 472d1d206d..dbd64487de 100644
--- a/ext/threads/t/join.t
+++ b/ext/threads/t/join.t
@@ -25,6 +25,8 @@ use Devel::Peek qw(Dump);
 sub ok {
     my ($ok, $name) = @_;
 
+    lock $test_id; # make print and increment atomic
+
     # You have to do it this way or VMS will get confused.
     print $ok ? "ok $test_id - $name\n" : "not ok $test_id - $name\n";
 
@@ -149,6 +151,7 @@ if ($^O eq 'linux') {
     # purpose is to incite a lot of calls to newCONSTSUB.  See the p5p
     # archives for the thread "maint@20974 or before broke mp2 ithreads test".
     use IO::File;
+    # this coredumped between #20930 and #21000
     $_->join for map threads->new(sub{ok($_, "stress newCONSTSUB")}), 1..2;
 }