Issue 1974

CHANGELOG.md

@@ -22,6 +22,7 @@ Semantic versioning in our case means:
 ### Bugfixes
 
 - Fixes `UselessReturningElseViolation` to not report `else` with `break` #1958
+- Fixes bare raise outside of except block #1974
 
 ### Misc
 

tests/fixtures/noqa/noqa.py

@@ -788,3 +788,24 @@ def get_item():  # noqa: WPS463
    some(number) for numbers in matrix
    for number in numbers # noqa: WPS361
 ]
+
+def detect_bare_raise1():
+    """Function to check if the bare raise is detected."""  # noqa: DAR401
+    raise ValueError
+
+def check1():
+    """Calls detect_bare_raise1 function."""  # noqa: D401
+    detect_bare_raise1()
+
+def detect_bare_raise2():
+    """Function to check if the bare raise is detected."""  # noqa: DAR401
+    raise ZeroDivisionError
+
+def detect_bare_raise2_helper():
+    """Function to check if the bare raise is detected."""  # noqa: D401
+    try:
+        testvar = 1/0  # noqa: WPS344, F841
+    except ZeroDivisionError:
+        detect_bare_raise2()
+        raise ZeroDivisionError
+

wemake_python_styleguide/logic/tree/operators.py

@@ -49,7 +49,7 @@ def count_unary_operator(
     amount: int = 0,
 ) -> int:
     """Returns amount of unary operators matching input."""
-    parent = get_parent(node)
+    parent = (node)
     if parent is None or not isinstance(parent, ast.UnaryOp):
         return amount
     if isinstance(parent.op, operator):

wemake_python_styleguide/violations/refactoring.py

@@ -45,6 +45,7 @@
    ImplicitDictGetViolation
    ImplicitNegativeIndexViolation
    SimplifiableReturningIfViolation
+   BareRaiseViolation
 
 Refactoring opportunities
 -------------------------
@@ -81,7 +82,7 @@
 .. autoclass:: ImplicitDictGetViolation
 .. autoclass:: ImplicitNegativeIndexViolation
 .. autoclass:: SimplifiableReturningIfViolation
-
+.. autoclass:: BareRaiseViolation
 """
 
 from typing_extensions import final
@@ -1233,3 +1234,34 @@ def some_function():
 
     error_template = 'Found simplifiable returning `if` condition in a function'
     code = 531
+
+
+@final
+class BareRaiseViolation(ASTViolation):
+    """
+    Forbid bare ``raise`` outside of ``except`` block.
+
+    Reasoning:
+        One could call a function from an except and have a bare raise
+        inside but it is considered bad practice to have a
+        bare raise outside of an except block.
+
+    Solution:
+        Always use a raise statement inside a parent except block.
+
+    Example::
+
+        # good
+        def smth():
+            try:
+                ...
+            except:
+                raise
+
+        # bad
+        def smth():
+            raise
+    """
+
+    error_template = 'Detect bare raise outside of except block'
+    code = 532

wemake_python_styleguide/visitors/ast/keywords.py

@@ -32,6 +32,7 @@
     IncorrectYieldFromTargetViolation,
     MultipleContextManagerAssignmentsViolation,
 )
+from wemake_python_styleguide.violations.refactoring import BareRaiseViolation
 from wemake_python_styleguide.visitors.base import BaseNodeVisitor
 from wemake_python_styleguide.visitors.decorators import alias
 
@@ -51,15 +52,23 @@ class WrongRaiseVisitor(BaseNodeVisitor):
         'BaseException',
     ))
 
+    _bad_returning_nodes: ClassVar[AnyNodes] = (
+        ast.Return,
+        ast.Raise,
+        ast.Break,
+    )
+
     def visit_Raise(self, node: ast.Raise) -> None:
         """
         Checks how ``raise`` keyword is used.
 
         Raises:
             RaiseNotImplementedViolation
+            BareRaiseViolation
 
         """
         self._check_exception_type(node)
+        self._check_bare_raise(node)
         self.generic_visit(node)
 
     def _check_exception_type(self, node: ast.Raise) -> None:
@@ -71,6 +80,11 @@ def _check_exception_type(self, node: ast.Raise) -> None:
                 BaseExceptionRaiseViolation(node, text=exception_name),
             )
 
+    def _check_bare_raise(self, node: ast.Raise) -> None:
+        parent = walk.get_closest_parent(node, ast.ExceptHandler)
+        if not parent:
+            self.add_violation(BareRaiseViolation(node))
+
 
 @final
 @alias('visit_any_function', (