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# Copyright (c) Meta Platforms, Inc. and affiliates.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
from textwrap import dedent
from typing import Callable
from unittest.mock import patch
import libcst as cst
from libcst._nodes.base import CSTValidationError
from libcst._parser.entrypoints import is_native
from libcst.testing.utils import data_provider, UnitTest
class ParseErrorsTest(UnitTest):
@data_provider(
{
# _wrapped_tokenize raises these exceptions
"wrapped_tokenize__invalid_token": (
lambda: cst.parse_module("'"),
dedent(
"""
Syntax Error @ 1:1.
"'" is not a valid token.
'
^
"""
).strip(),
),
"wrapped_tokenize__expected_dedent": (
lambda: cst.parse_module("if False:\n pass\n pass"),
dedent(
"""
Syntax Error @ 3:1.
Inconsistent indentation. Expected a dedent.
pass
^
"""
).strip(),
),
"wrapped_tokenize__mismatched_braces": (
lambda: cst.parse_module("abcd)"),
dedent(
"""
Syntax Error @ 1:5.
Encountered a closing brace without a matching opening brace.
abcd)
^
"""
).strip(),
),
# _base_parser raises these exceptions
"base_parser__unexpected_indent": (
lambda: cst.parse_module(" abcd"),
dedent(
"""
Syntax Error @ 1:5.
Incomplete input. Unexpectedly encountered an indent.
abcd
^
"""
).strip(),
),
"base_parser__unexpected_dedent": (
lambda: cst.parse_module("if False:\n (el for el\n"),
dedent(
"""
Syntax Error @ 3:1.
Incomplete input. Encountered a dedent, but expected 'in'.
(el for el
^
"""
).strip(),
),
"base_parser__multiple_possibilities": (
lambda: cst.parse_module("try: pass"),
dedent(
"""
Syntax Error @ 2:1.
Incomplete input. Encountered end of file (EOF), but expected 'except', or 'finally'.
try: pass
^
"""
).strip(),
),
# conversion functions raise these exceptions.
# `_base_parser` is responsible for attaching location information.
"convert_nonterminal__dict_unpacking": (
lambda: cst.parse_expression("{**el for el in []}"),
dedent(
"""
Syntax Error @ 1:19.
dict unpacking cannot be used in dict comprehension
{**el for el in []}
^
"""
).strip(),
),
"convert_nonterminal__arglist_non_default_after_default": (
lambda: cst.parse_statement("def fn(first=None, second): ..."),
dedent(
"""
Syntax Error @ 1:26.
Cannot have a non-default argument following a default argument.
def fn(first=None, second): ...
^
"""
).strip(),
),
"convert_nonterminal__arglist_trailing_param_star_without_comma": (
lambda: cst.parse_statement("def fn(abc, *): ..."),
dedent(
"""
Syntax Error @ 1:14.
Named (keyword) arguments must follow a bare *.
def fn(abc, *): ...
^
"""
).strip(),
),
"convert_nonterminal__arglist_trailing_param_star_with_comma": (
lambda: cst.parse_statement("def fn(abc, *,): ..."),
dedent(
"""
Syntax Error @ 1:15.
Named (keyword) arguments must follow a bare *.
def fn(abc, *,): ...
^
"""
).strip(),
),
"convert_nonterminal__class_arg_positional_after_keyword": (
lambda: cst.parse_statement("class Cls(first=None, second): ..."),
dedent(
"""
Syntax Error @ 2:1.
Positional argument follows keyword argument.
class Cls(first=None, second): ...
^
"""
).strip(),
),
"convert_nonterminal__class_arg_positional_expansion_after_keyword": (
lambda: cst.parse_statement("class Cls(first=None, *second): ..."),
dedent(
"""
Syntax Error @ 2:1.
Positional argument follows keyword argument.
class Cls(first=None, *second): ...
^
"""
).strip(),
),
}
)
def test_parser_syntax_error_str(
self, parse_fn: Callable[[], object], expected: str
) -> None:
with self.assertRaises(cst.ParserSyntaxError) as cm:
parse_fn()
# make sure str() doesn't blow up
self.assertIn("Syntax Error", str(cm.exception))
if not is_native():
self.assertEqual(str(cm.exception), expected)
def test_native_fallible_into_py(self) -> None:
with patch("libcst._nodes.expression.Name._validate") as await_validate:
await_validate.side_effect = CSTValidationError("validate is broken")
with self.assertRaises((SyntaxError, cst.ParserSyntaxError)):
cst.parse_module("foo")
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