Fix WPS220 for top-level Ellipsis (#2897)

CHANGELOG.md

@@ -17,6 +17,13 @@ Semantic versioning in our case means:
   change the client facing API, change code conventions significantly, etc.
 
 
+## 0.19.1
+
+### Bugfixes
+
+- Fixes `TooDeepNestingViolation` not to trigger on `...`
+
+
 ## 0.19.0
 
 This minor version will be the last release with all the `flake8` plugins.

tests/test_visitors/test_ast/test_complexity/test_offset_visitor.py

@@ -9,7 +9,7 @@
 nested_if = """
 def container():
     if True:
-        x = 1
+        ...  # this needs to be an ellipsis for the test
 """
 
 nested_if2 = """
@@ -85,6 +85,17 @@ async def update_control():
                                                            'point': 1})
 """
 
+# Only ellipsis in the top level function definition is fine:
+
+top_level_function_ellipsis = """
+def function_with_really_long_name(): ...
+"""
+
+top_level_method_ellipsis = """
+class MyClass:
+    def function_with_really_long_name(self): ...
+"""
+
 
 @pytest.mark.parametrize('code', [
     nested_if,
@@ -108,6 +119,8 @@ async def update_control():
             reason='Pattern matching was added in 3.10',
         ),
     ),
+    top_level_function_ellipsis,
+    top_level_method_ellipsis,
 ])
 def test_nested_offset(
     assert_errors,

wemake_python_styleguide/visitors/ast/complexity/offset.py

@@ -3,6 +3,8 @@
 
 from typing_extensions import final
 
+from wemake_python_styleguide.compat.aliases import FunctionNodes
+from wemake_python_styleguide.logic.nodes import get_parent
 from wemake_python_styleguide.violations.complexity import (
     TooDeepNestingViolation,
 )
@@ -55,6 +57,15 @@ def visit_line_expression(self, node: ast.AST) -> None:
         self.generic_visit(node)
 
     def _check_offset(self, node: ast.AST) -> None:
+        is_function_ellipsis = (
+            isinstance(get_parent(node), FunctionNodes) and
+            isinstance(node, ast.Expr) and
+            isinstance(node.value, ast.Constant) and
+            node.value.value is Ellipsis
+        )
+        if is_function_ellipsis:
+            return
+
         offset = getattr(node, 'col_offset', 0)
         baseline = self._max_offset_blocks * 4
         if offset > baseline: