Support ast.TryStar and except* (#2891)

CHANGELOG.md

@@ -50,6 +50,13 @@ Semantic versioning in our case means:
 - Fixes `ObjectInBaseClassesListViolation`, `UnpythonicGetterSetterViolation`,
   `ImplicitInConditionViolation`, `RedundantSubscriptViolation`,
   `TooLongCompareViolation` to include better error details
+- Fixes `TooDeepNestingViolation` for `TryStar` and `Match` statements
+- Fixes `TooLongTryBodyViolation` and `TooManyExceptCasesViolation`
+  to work for `TryStar` statements as well
+- Fixes `UselessNodeViolation` to work with `TryStar`
+- Fixes `DuplicateExceptionViolation` to work with `TryStar`
+- Fixes `TryExceptMultipleReturnPathViolation` to work with `TryStar`
+- Fixes `IncorrectExceptOrderViolation` to work with `TryStar`
 
 ### Misc
 

setup.cfg

@@ -128,6 +128,9 @@ rules =
   # 3.10
   "sys_version_info < (3, 10)": py-lt-310
   "sys_version_info >= (3, 10)": py-gte-310
+  # 3.11
+  "sys_version_info < (3, 11)": py-lt-311
+  "sys_version_info >= (3, 11)": py-gte-311
   # 3.12
   "sys_version_info < (3, 12)": py-lt-312
   "sys_version_info >= (3, 12)": py-gte-312

tests/test_visitors/conftest.py

@@ -23,7 +23,7 @@ def assert_errors():
     """Helper function to assert visitor violations."""
     def factory(
         visitor: BaseVisitor,
-        errors: Sequence[str],
+        expected_errors: Sequence[str],
         *,
         ignored_types: _IgnoredTypes = None,
     ) -> None:
@@ -36,10 +36,10 @@ def factory(
         else:
             real_errors = visitor.violations
 
-        assert len(errors) == len(real_errors)
+        assert len(expected_errors) == len(real_errors)
 
         for index, error in enumerate(real_errors):
-            assert error.code == errors[index].code
+            assert error.code == expected_errors[index].code
             if isinstance(error, (ASTViolation, TokenizeViolation)):
                 assert error._node is not None  # noqa: WPS437
                 assert error._location() != (0, 0)  # noqa: WPS437

tests/test_visitors/test_ast/test_complexity/test_counts/test_try_body_length.py

@@ -1,5 +1,6 @@
 import pytest
 
+from wemake_python_styleguide.compat.constants import PY311
 from wemake_python_styleguide.violations.complexity import (
     TooLongTryBodyViolation,
 )
@@ -21,6 +22,13 @@
     ...
 """
 
+try_star_except = """
+try:
+    {0}
+except* ValueError:
+    ...
+"""
+
 try_except_with_else = """
 try:
     {0}
@@ -77,10 +85,16 @@
     simple_try_except,
     try_except_with_else,
     full_except_with_else,
+    pytest.param(
+        try_star_except,
+        marks=pytest.mark.skipif(
+            not PY311,
+            reason='ExceptionGroup was added in python 3.11',
+        ),
+    ),
 ])
 def test_try_body_count_default(
     assert_errors,
-    assert_error_text,
     parse_ast_tree,
     default_options,
     code,
@@ -105,6 +119,13 @@ def test_try_body_count_default(
     simple_try_except,
     try_except_with_else,
     full_except_with_else,
+    pytest.param(
+        try_star_except,
+        marks=pytest.mark.skipif(
+            not PY311,
+            reason='ExceptionGroup was added in python 3.11',
+        ),
+    ),
 ])
 def test_try_body_wrong_custom_options(
     assert_errors,
@@ -137,6 +158,13 @@ def test_try_body_wrong_custom_options(
     simple_try_except,
     try_except_with_else,
     full_except_with_else,
+    pytest.param(
+        try_star_except,
+        marks=pytest.mark.skipif(
+            not PY311,
+            reason='ExceptionGroup was added in python 3.11',
+        ),
+    ),
 ])
 def test_try_body_count_custom_options(
     assert_errors,
@@ -165,6 +193,13 @@ def test_try_body_count_custom_options(
     simple_try_except,
     try_except_with_else,
     full_except_with_else,
+    pytest.param(
+        try_star_except,
+        marks=pytest.mark.skipif(
+            not PY311,
+            reason='ExceptionGroup was added in python 3.11',
+        ),
+    ),
 ])
 def test_try_body_correct_default(
     assert_errors,

tests/test_visitors/test_ast/test_complexity/test_counts/test_try_except.py

@@ -1,5 +1,6 @@
 import pytest
 
+from wemake_python_styleguide.compat.constants import PY311
 from wemake_python_styleguide.violations.complexity import (
     TooManyExceptCasesViolation,
 )
@@ -56,15 +57,39 @@
     ...
 """
 
+complex_try_star_except = """
+try:
+    ...
+except* ValueError:
+    ...
+except* KeyError:
+    ...
+except* IndexError as exc:
+    ...
+except* TypeError:
+    ...
+"""
+
 
+@pytest.mark.parametrize('code', [
+    complex_try_except,
+    pytest.param(
+        complex_try_star_except,
+        marks=pytest.mark.skipif(
+            not PY311,
+            reason='ExceptionGroup was added in python 3.11',
+        ),
+    ),
+])
 def test_try_except_count_default(
     assert_errors,
     assert_error_text,
     parse_ast_tree,
+    code,
     default_options,
 ):
     """Testing that default settings raise a warning."""
-    tree = parse_ast_tree(complex_try_except)
+    tree = parse_ast_tree(code)
 
     visitor = TryExceptVisitor(default_options, tree=tree)
     visitor.run()

tests/test_visitors/test_ast/test_complexity/test_offset_visitor.py

@@ -1,5 +1,6 @@
 import pytest
 
+from wemake_python_styleguide.compat.constants import PY310, PY311
 from wemake_python_styleguide.visitors.ast.complexity.offset import (
     OffsetVisitor,
     TooDeepNestingViolation,
@@ -40,6 +41,14 @@ def container():
             raise
 """
 
+nested_try_star = """
+def container():
+    try:
+        ...
+    except* ...:
+        ...
+"""
+
 nested_with = """
 def container():
     with open('some') as temp:
@@ -52,6 +61,13 @@ def container():
         continue
 """
 
+nested_match = """
+def container():
+    match ...:
+        case 1:
+            ...
+"""
+
 real_nested_values = """
 def container():
     if some > 1:
@@ -76,8 +92,22 @@ async def update_control():
     nested_for,
     nested_try,
     nested_try2,
+    pytest.param(
+        nested_try_star,
+        marks=pytest.mark.skipif(
+            not PY311,
+            reason='ExceptionGroup was added in 3.11',
+        ),
+    ),
     nested_with,
     nested_while,
+    pytest.param(
+        nested_match,
+        marks=pytest.mark.skipif(
+            not PY310,
+            reason='Pattern matching was added in 3.10',
+        ),
+    ),
 ])
 def test_nested_offset(
     assert_errors,
@@ -119,8 +149,10 @@ def test_nested_offset_regression320(
     (nested_for, 1),
     (nested_try, 2),
     (nested_try2, 4),
+    (nested_try_star, 2),
     (nested_with, 1),
     (nested_while, 1),
+    (nested_match, 1),
 ])
 def test_nested_offset_errors(
     monkeypatch,
@@ -132,6 +164,11 @@ def test_nested_offset_errors(
     mode,
 ):
     """Testing that nested expressions are restricted."""
+    if code == nested_try_star and not PY311:
+        pytest.skip(reason='ExceptionGroup was added in 3.11')
+    if code == nested_match and not PY310:
+        pytest.skip(reason='Pattern matching was added in 3.10')
+
     tree = parse_ast_tree(mode(code))
 
     monkeypatch.setattr(OffsetVisitor, '_max_offset_blocks', 1)

tests/test_visitors/test_ast/test_exceptions/test_duplicate_exceptions.py

@@ -1,5 +1,6 @@
 import pytest
 
+from wemake_python_styleguide.compat.constants import PY311
 from wemake_python_styleguide.violations.best_practices import (
     DuplicateExceptionViolation,
 )
@@ -98,6 +99,15 @@
     ...
 """
 
+wrong_simple_star = """
+try:
+    ...
+except* ValueError as ex:
+    ...
+except* ValueError:
+    ...
+"""
+
 
 @pytest.mark.parametrize('code', [
     correct_bare_except,
@@ -128,6 +138,13 @@ def test_correct_exceptions(
     wrong_simple,
     wrong_single_tuple,
     wrong_different_tuples,
+    pytest.param(
+        wrong_simple_star,
+        marks=pytest.mark.skipif(
+            not PY311,
+            reason='ExceptionGroup was added in python 3.11',
+        ),
+    ),
 ])
 def test_duplicate_exceptions(
     assert_errors,

tests/test_visitors/test_ast/test_exceptions/test_exception_order.py

@@ -1,5 +1,6 @@
 import pytest
 
+from wemake_python_styleguide.compat.constants import PY311
 from wemake_python_styleguide.violations.best_practices import (
     IncorrectExceptOrderViolation,
 )
@@ -16,6 +17,15 @@
     ...
 """
 
+exception_star_template = """
+try:
+    ...
+except {0}:
+    ...
+except {1}:
+    ...
+"""
+
 custom_exception_template1 = """
 try:
     ...
@@ -41,6 +51,13 @@
 
 @pytest.mark.parametrize('code', [
     exception_template,
+    pytest.param(
+        exception_star_template,
+        marks=pytest.mark.skipif(
+            not PY311,
+            reason='ExceptionGroup was added in python 3.11',
+        ),
+    ),
     custom_exception_template1,
     custom_exception_template2,
 ])
@@ -67,6 +84,13 @@ def test_correct_order_exception(
 
 @pytest.mark.parametrize('code', [
     exception_template,
+    pytest.param(
+        exception_star_template,
+        marks=pytest.mark.skipif(
+            not PY311,
+            reason='ExceptionGroup was added in python 3.11',
+        ),
+    ),
     custom_exception_template1,
     custom_exception_template2,
 ])

tests/test_visitors/test_ast/test_exceptions/test_finally_return_path.py

@@ -1,5 +1,6 @@
 import pytest
 
+from wemake_python_styleguide.compat.constants import PY311
 from wemake_python_styleguide.violations.best_practices import (
     TryExceptMultipleReturnPathViolation,
 )
@@ -185,6 +186,17 @@ def function():
             {0}
 """
 
+wrong_try_star_finally = """
+def function():
+    for _ in range(10):
+        try:
+            {0}
+        except* TypeError:
+            ...
+        finally:
+            {0}
+"""
+
 wrong_except_finally = """
 def function():
     for _ in range(10):
@@ -372,6 +384,13 @@ def function():
     wrong_multiple_except_finally3,
     wrong_else_finally,
     wrong_try_finally,
+    pytest.param(
+        wrong_try_star_finally,
+        marks=pytest.mark.skipif(
+            not PY311,
+            reason='ExceptionGroup was added in python 3.11',
+        ),
+    ),
     wrong_try_else,
     wrong_try_except_else,
     wrong_all1,