diff --git a/Lib/ast.py b/Lib/ast.py index 157a8332ebcc5c..0c88bcf4c821ea 100644 --- a/Lib/ast.py +++ b/Lib/ast.py @@ -59,11 +59,12 @@ def literal_eval(node_or_string): 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) @@ -82,6 +83,8 @@ def _convert(node): elif isinstance(node, Set): return set(map(_convert, node.elts)) 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 3e8a39dc41047e..8887558ce4c31a 100644 --- a/Lib/test/test_ast.py +++ b/Lib/test/test_ast.py @@ -869,6 +869,12 @@ def test_literal_eval_complex(self): 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 00000000000000..81f9e937a2bff4 --- /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.
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