From 803bd7c91c63f8f263bed592a33b10cf69f567cf Mon Sep 17 00:00:00 2001
From: David Mitchell <davem@iabyn.com>
Date: Fri, 22 Mar 2019 15:43:56 +0000
Subject: [PATCH] fix leak in BEGIN { threads->new(...) }
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Normally by the time we reach perl_destruct(), PL_parser should be null
due to having its original (null) value restored by SAVEt_PARSER during
leaving scope (usually before run-time starts in fact).  But if a thread
is created within a BEGIN block, the parser is duped, but the
SAVEt_PARSER savestack entry isn't. So PL_parser never gets cleaned up.
Clean it up in perl_destruct() instead. This is a bit of a hack.

Signed-off-by: Petr Písař <ppisar@redhat.com>
---
 perl.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/perl.c b/perl.c
index cdefa99018..1ef425bb25 100644
--- a/perl.c
+++ b/perl.c
@@ -668,6 +668,21 @@ perl_destruct(pTHXx)
     FREETMPS;
     assert(PL_scopestack_ix == 0);
 
+    /* normally when we get here, PL_parser should be null due to having
+     * its original (null) value restored by SAVEt_PARSER during leaving
+     * scope (usually before run-time starts in fact).
+     * But if a thread is created within a BEGIN block, the parser is
+     * duped, but the SAVEt_PARSER savestack entry isn't. So PL_parser
+     * never gets cleaned up.
+     * Clean it up here instead. This is a bit of a hack.
+     */
+    if (PL_parser) {
+        /* stop parser_free() stomping on PL_curcop */
+        PL_parser->saved_curcop = PL_curcop;
+        parser_free(PL_parser);
+    }
+
+
     /* Need to flush since END blocks can produce output */
     /* flush stdout separately, since we can identify it */
 #ifdef USE_PERLIO
-- 
2.20.1