From c4b56e312d6776893fe54c43ee65a242cb5a6759 Mon Sep 17 00:00:00 2001
From: mwilliams <mwilliams@fb.com>
Date: Wed, 3 Apr 2013 19:24:33 -0700
Subject: [PATCH] Fix UnsetM with global base

If the global was not defined, it would try to return
a pointer into the MInstrCtx, which was not passed in.

We dont actually need it though, because in that case we can
just return a pointer to init_null_variant.
---
 hphp/runtime/vm/translator/hopt/vectortranslator.cpp | 3 +--
 hphp/test/vm/unset_undef_g.php                       | 5 +++++
 hphp/test/vm/unset_undef_g.php.exp                   | 0
 3 files changed, 6 insertions(+), 2 deletions(-)
 create mode 100644 hphp/test/vm/unset_undef_g.php
 create mode 100644 hphp/test/vm/unset_undef_g.php.exp

diff --git a/hphp/runtime/vm/translator/hopt/vectortranslator.cpp b/hphp/runtime/vm/translator/hopt/vectortranslator.cpp
index 46459870b..cf4a3236d 100644
--- a/hphp/runtime/vm/translator/hopt/vectortranslator.cpp
+++ b/hphp/runtime/vm/translator/hopt/vectortranslator.cpp
@@ -600,8 +600,7 @@ static inline TypedValue* baseGImpl(TypedValue *key,
       varEnv->set(name, &tv);
       base = varEnv->lookup(name);
     } else {
-      tvWriteNull(&mis->tvScratch);
-      base = &mis->tvScratch;
+      return const_cast<TypedValue*>(init_null_variant.asTypedValue());
     }
   }
   decRefStr(name);
diff --git a/hphp/test/vm/unset_undef_g.php b/hphp/test/vm/unset_undef_g.php
new file mode 100644
index 000000000..3a1e6c52d
--- /dev/null
+++ b/hphp/test/vm/unset_undef_g.php
@@ -0,0 +1,5 @@
+<?php
+function test($t) {
+  unset($GLOBALS['foo']['bar']);
+}
+test(null);
diff --git a/hphp/test/vm/unset_undef_g.php.exp b/hphp/test/vm/unset_undef_g.php.exp
new file mode 100644
index 000000000..e69de29bb