bpo-40355: Improve error messages in ast.literal_eval with malformed Dict nodes (GH-19868)
Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
diff --git a/Lib/ast.py b/Lib/ast.py
index 5c68c4a..7a43581 100644
--- a/Lib/ast.py
+++ b/Lib/ast.py
@@ -62,11 +62,12 @@
node_or_string = parse(node_or_string, mode='eval')
if isinstance(node_or_string, Expression):
node_or_string = node_or_string.body
+ def _raise_malformed_node(node):
+ raise ValueError(f'malformed node or string: {node!r}')
def _convert_num(node):
- if isinstance(node, Constant):
- if type(node.value) in (int, float, complex):
- return node.value
- raise ValueError('malformed node or string: ' + repr(node))
+ if not isinstance(node, Constant) or type(node.value) not in (int, float, complex):
+ _raise_malformed_node(node)
+ return node.value
def _convert_signed_num(node):
if isinstance(node, UnaryOp) and isinstance(node.op, (UAdd, USub)):
operand = _convert_num(node.operand)
@@ -88,6 +89,8 @@
node.func.id == 'set' and node.args == node.keywords == []):
return set()
elif isinstance(node, Dict):
+ if len(node.keys) != len(node.values):
+ _raise_malformed_node(node)
return dict(zip(map(_convert, node.keys),
map(_convert, node.values)))
elif isinstance(node, BinOp) and isinstance(node.op, (Add, Sub)):
diff --git a/Lib/test/test_ast.py b/Lib/test/test_ast.py
index 9063b3d..a8a13fd 100644
--- a/Lib/test/test_ast.py
+++ b/Lib/test/test_ast.py
@@ -965,6 +965,12 @@
self.assertRaises(ValueError, ast.literal_eval, '3+(0+6j)')
self.assertRaises(ValueError, ast.literal_eval, '-(3+6j)')
+ def test_literal_eval_malformed_dict_nodes(self):
+ malformed = ast.Dict(keys=[ast.Constant(1), ast.Constant(2)], values=[ast.Constant(3)])
+ self.assertRaises(ValueError, ast.literal_eval, malformed)
+ malformed = ast.Dict(keys=[ast.Constant(1)], values=[ast.Constant(2), ast.Constant(3)])
+ self.assertRaises(ValueError, ast.literal_eval, malformed)
+
def test_bad_integer(self):
# issue13436: Bad error message with invalid numeric values
body = [ast.ImportFrom(module='time',
diff --git a/Misc/NEWS.d/next/Library/2020-05-02-14-24-48.bpo-40355.xTujaB.rst b/Misc/NEWS.d/next/Library/2020-05-02-14-24-48.bpo-40355.xTujaB.rst
new file mode 100644
index 0000000..81f9e93
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-05-02-14-24-48.bpo-40355.xTujaB.rst
@@ -0,0 +1,2 @@
+Improve error reporting in :func:`ast.literal_eval` in the presence of malformed :class:`ast.Dict`
+nodes instead of silently ignoring any non-conforming elements. Patch by Curtis Bucher.