make MULTICALL safe across cxstack reallocs

[perl #115602]
MUTLICALL sets a local var, cx, to point to the current context stack
frame. When a function is called, the context stack might be realloc()ed,
in which case cx would point to freed memory.

1 files changed, 14 insertions, 1 deletions

diff --git a/ext/XS-APItest/t/multicall.t b/ext/XS-APItest/t/multicall.t
index 983f5fd016..f96f62e743 100644
--- a/ext/XS-APItest/t/multicall.t
+++ b/ext/XS-APItest/t/multicall.t
@@ -7,7 +7,7 @@
 use warnings;
 use strict;
 
-use Test::More tests => 6;
+use Test::More tests => 7;
 use XS::APItest;
 
 
@@ -48,3 +48,16 @@ use XS::APItest;
     is($destroyed, 1, "f now destroyed");
 
 }
+
+# [perl #115602]
+# deep recursion realloced the CX stack, but the dMULTICALL local var
+# 'cx' still pointed to the old one.
+# Thius doesn;t actually test the failure (I couldn't think of a way to
+# get the failure to show at the perl level) but it allows valgribnd or
+# similar to spot any errors.
+
+{
+    sub rec { my $c = shift; rec($c-1) if $c > 0 };
+    my @r = XS::APItest::multicall_each { rec(90) } 1,2,3;
+    pass("recursion");
+}