Fix bug added when refactoring, document some new methods.

Author: TysonAndre

ext/spl/spl_observer.c

@@ -145,6 +145,7 @@ static spl_SplObjectStorageElement *spl_object_storage_create_element(zend_objec
 	return pelement;
 } /* }}} */
 
+/* A faster version of spl_object_storage_attach used when neither SplObjectStorage->getHash nor SplObjectStorage->offsetSet is overridden. */
 static spl_SplObjectStorageElement *spl_object_storage_attach_handle(spl_SplObjectStorage *intern, zend_object *obj, zval *inf) /* {{{ */
 {
 	uint32_t handle = obj->handle;
@@ -179,6 +180,7 @@ spl_SplObjectStorageElement *spl_object_storage_attach(spl_SplObjectStorage *int
 	if (EXPECTED(!(intern->flags & SOS_OVERRIDDEN_WRITE_DIMENSION))) {
 		return spl_object_storage_attach_handle(intern, obj, inf);
 	}
+	/* getHash or offsetSet is overridden. */
 
 	spl_SplObjectStorageElement *pelement, element;
 	zend_hash_key key;
@@ -198,7 +200,7 @@ spl_SplObjectStorageElement *spl_object_storage_attach(spl_SplObjectStorage *int
 		}
 		spl_object_storage_free_hash(intern, &key);
 		/* Call the old value's destructor last, in case it moves the entry */
-		zval_ptr_dtor(&pelement->inf);
+		zval_ptr_dtor(&zv_inf);
 		return pelement;
 	}