From: David Mitchell <davem@iabyn.com>
Date: Fri, 16 Nov 2012 18:04:49 +0000 (+0000)
Subject: clone() wasn't cloning the whole stack
X-Git-Tag: v5.17.6~58
X-Git-Url: https://perl5.git.perl.org/perl5.git/commitdiff_plain/ba593adc2b8b59175ac3c28b7b41aef7a74908e2

clone() wasn't cloning the whole stack

When cloning stacks (e.g. for fake fork), the stack is cloned
by copying the stack AV pointed to by PL_curstackinfo; but the
AvFILL on that AV may not be up to date, resulting in the top N
items of the stack not being cloned. Fix by saving PL_stack_sp
back into AvFILL(PL_curstack) before cloning
---

diff --git a/ext/XS-APItest/t/clone-with-stack.t b/ext/XS-APItest/t/clone-with-stack.t
index 943a123..7a0cd29 100644
--- a/ext/XS-APItest/t/clone-with-stack.t
+++ b/ext/XS-APItest/t/clone-with-stack.t
@@ -17,7 +17,7 @@ if (not $Config{'useithreads'}) {
     skip_all("clone_with_stack requires threads");
 }
 
-plan(3);
+plan(4);
 
 fresh_perl_is( <<'----', <<'====', undef, "minimal clone_with_stack" );
 use XS::APItest;
@@ -51,3 +51,17 @@ ok
 ====
 
 }
+
+{
+    fresh_perl_is( <<'----', <<'====', undef, "clone stack" );
+use XS::APItest;
+sub f {
+    clone_with_stack();
+    0..4;
+}
+print 'X-', 'Y-', join(':', f()), "-Z\n";
+----
+X-Y-0:1:2:3:4-Z
+====
+
+}
diff --git a/sv.c b/sv.c
index 682ac45..4d7219d 100644
--- a/sv.c
+++ b/sv.c
@@ -13493,6 +13493,11 @@ perl_clone_using(PerlInterpreter *proto_perl, UV flags,
 	Newxz(PL_scopestack_name, PL_scopestack_max, const char *);
 	Copy(proto_perl->Iscopestack_name, PL_scopestack_name, PL_scopestack_ix, const char *);
 #endif
+        /* reset stack AV to correct length before its duped via
+         * PL_curstackinfo */
+        AvFILLp(proto_perl->Icurstack) =
+                            proto_perl->Istack_sp - proto_perl->Istack_base;
+
 	/* NOTE: si_dup() looks at PL_markstack */
 	PL_curstackinfo		= si_dup(proto_perl->Icurstackinfo, param);