diff options
Diffstat (limited to 'astroid/helpers.py')
| -rw-r--r-- | astroid/helpers.py | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/astroid/helpers.py b/astroid/helpers.py index 8ab68799..7a9fae17 100644 --- a/astroid/helpers.py +++ b/astroid/helpers.py @@ -1,6 +1,9 @@ # Copyright (c) 2015-2020 Claudiu Popa <pcmanticore@gmail.com> # Copyright (c) 2015-2016 Ceridwen <ceridwenv@gmail.com> # Copyright (c) 2018 Bryce Guinta <bryce.paul.guinta@gmail.com> +# Copyright (c) 2020 Simon Hewitt <si@sjhewitt.co.uk> +# Copyright (c) 2020 Bryce Guinta <bryce.guinta@protonmail.com> +# Copyright (c) 2020 Ram Rachum <ram@rachum.com> # Licensed under the LGPL: https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html # For details: https://github.com/PyCQA/astroid/blob/master/COPYING.LESSER @@ -237,13 +240,32 @@ def object_len(node, context=None): :raises AstroidTypeError: If an invalid node is returned from __len__ method or no __len__ method exists :raises InferenceError: If the given node cannot be inferred - or if multiple nodes are inferred + or if multiple nodes are inferred or if the code executed in python + would result in a infinite recursive check for length :rtype int: Integer length of node """ # pylint: disable=import-outside-toplevel; circular import from astroid.objects import FrozenSet inferred_node = safe_infer(node, context=context) + + # prevent self referential length calls from causing a recursion error + # see https://github.com/PyCQA/astroid/issues/777 + node_frame = node.frame() + if ( + isinstance(node_frame, scoped_nodes.FunctionDef) + and node_frame.name == "__len__" + and inferred_node is not None + and inferred_node._proxied == node_frame.parent + ): + message = ( + "Self referential __len__ function will " + "cause a RecursionError on line {} of {}".format( + node.lineno, node.root().file + ) + ) + raise exceptions.InferenceError(message) + if inferred_node is None or inferred_node is util.Uninferable: raise exceptions.InferenceError(node=node) if isinstance(inferred_node, nodes.Const) and isinstance( |