SPL object not implementing Traversable is now a recoverable error

Summary: When an argument to a call like `iterator_count()` did not implement `Traversable`, this used to throw a pure `fatal`. Since 5.6, it now throws a `catchable fatal` (i.e. `E_RECOVERABLE_ERROR` in PHP). Let's match.

Reviewed By: @ptarjan

Differential Revision: D1623321

hphp/runtime/ext/ext_spl.cpp

@@ -227,12 +227,14 @@ Variant f_class_uses(const Variant& obj, bool autoload /* = true */) {
   return ret;
 }
 
-Object get_traversable_object_iterator(const Variant& obj) {
-  if (!obj.isObject() ||
-      !obj.getObjectData()->instanceof(SystemLib::s_TraversableClass)) {
-    raise_error("Argument must implement interface Traversable");
+#define CHECK_TRAVERSABLE_IMPL(obj, ret) \
+  if (!obj.isObject() || \
+      !obj.getObjectData()->instanceof(SystemLib::s_TraversableClass)) { \
+    raise_recoverable_error("Argument must implement interface Traversable"); \
+    return ret; \
   }
 
+Object get_traversable_object_iterator(const Variant& obj) {
   bool isIteratorAggregate;
   Object itObj = obj.getObjectData()
     ->iterableObject(isIteratorAggregate, true);
@@ -256,6 +258,7 @@ Object get_traversable_object_iterator(const Variant& obj) {
 
 Variant f_iterator_apply(const Variant& obj, const Variant& func,
                          const Array& params /* = null_array */) {
+  CHECK_TRAVERSABLE_IMPL(obj, 0);
   Object pobj = get_traversable_object_iterator(obj);
   pobj->o_invoke_few_args(s_rewind, 0);
   int64_t count = 0;
@@ -270,6 +273,7 @@ Variant f_iterator_apply(const Variant& obj, const Variant& func,
 }
 
 Variant f_iterator_count(const Variant& obj) {
+  CHECK_TRAVERSABLE_IMPL(obj, 0);
   Object pobj = get_traversable_object_iterator(obj);
   pobj->o_invoke_few_args(s_rewind, 0);
   int64_t count = 0;
@@ -281,8 +285,9 @@ Variant f_iterator_count(const Variant& obj) {
 }
 
 Variant f_iterator_to_array(const Variant& obj, bool use_keys /* = true */) {
-  Object pobj = get_traversable_object_iterator(obj);
   Array ret(Array::Create());
+  CHECK_TRAVERSABLE_IMPL(obj, ret);
+  Object pobj = get_traversable_object_iterator(obj);
 
   pobj->o_invoke_few_args(s_rewind, 0);
   while (same(pobj->o_invoke_few_args(s_valid, 0), true)) {

hphp/test/slow/iterator/iterator_to_array.php.expectf

@@ -15,4 +15,4 @@ array(3) {
   int(3)
 }
 
-Fatal error: Argument must implement interface Traversable in %s/test/slow/iterator/iterator_to_array.php on line 11
+Catchable fatal error: Argument must implement interface Traversable in %s/test/slow/iterator/iterator_to_array.php on line 11