Throw from SplObjectStorage::current() for invalid iterator

Accessing key()/current() on an invalid iterator is an error
condition. Throw instead of returning null.

Author: nikic

ext/spl/spl_observer.c

@@ -566,7 +566,8 @@ PHP_METHOD(SplObjectStorage, current)
 	}
 
 	if ((element = zend_hash_get_current_data_ptr_ex(&intern->storage, &intern->pos)) == NULL) {
-		return;
+		zend_throw_exception(spl_ce_RuntimeException, "Called current() on invalid iterator", 0);
+		RETURN_THROWS();
 	}
 	ZVAL_OBJ_COPY(return_value, element->obj);
 } /* }}} */

ext/spl/tests/SplObjectStorage_current_empty_storage.phpt

@@ -1,14 +1,20 @@
 --TEST--
-Check that SplObjectStorage::current returns NULL when storage is empty
+Check that SplObjectStorage::current() throws when iterator invalid
 --CREDITS--
 PHPNW Testfest 2009 - Simon Westcott (swestcott@gmail.com)
 --FILE--
 <?php
 
 $s = new SplObjectStorage();
 
-var_dump($s->current());
+var_dump($s->valid());
+try {
+    var_dump($s->current());
+} catch (RuntimeException $e) {
+    echo $e->getMessage(), "\n";
+}
 
 ?>
 --EXPECT--
-NULL
+bool(false)
+Called current() on invalid iterator