Closes #1207

CHANGELOG.md

@@ -70,6 +70,8 @@ Semantic versioning in our case means:
   and other builtin functions without keyword arguments
 - Fixes `WPS221` reporting differently on different `python` versions
 - Fixes `WPS221` reporting nested variable annotations
+- Fixes `WPS509` not reporting nested ternary in grandchildren of `if`
+- Fixes `WPS509` not reporting nested ternary in ternary
 
 ### Misc
 

tests/test_visitors/test_ast/test_compares/test_nested_ternary.py

@@ -2,6 +2,7 @@
 
 import pytest
 
+from wemake_python_styleguide.compat.constants import PY38
 from wemake_python_styleguide.violations.refactoring import (
     NestedTernaryViolation,
 )
@@ -15,37 +16,53 @@
 wrong_compare4 = '(a if b else c) == x == y'
 wrong_compare5 = 'x == (a if b else c) == y'
 wrong_compare6 = 'x != (a if b else c)'
+wrong_compare7 = 'x != call(a if b else c)'
 
 wrong_boolop1 = 'x and (a if b else c)'
 wrong_boolop2 = 'x or (a if b else c)'
 wrong_boolop3 = '(a if b else c) or x'
 wrong_boolop4 = 'x and (a if b else c) or y'
 wrong_boolop5 = 'x and y or (a if b else c)'
 wrong_boolop6 = '(a if b else c) and x or y'
+wrong_boolop7 = 'call(a if b else c) and x or y'
 
 wrong_binop1 = 'x + (a if b else c)'
 wrong_binop2 = 'x - (a if b else c)'
 wrong_binop3 = '(a if b else c) / y'
 wrong_binop4 = 'x + (a if b else c) - y'
 wrong_binop5 = 'x + y - (a if b else c)'
 wrong_binop6 = '(a if b else c) * x / y'
+wrong_binop7 = 'some(a if b else c) * x / y'
 
 wrong_unary1 = '+(a if b else c)'
 wrong_unary2 = '-(a if b else c)'
 wrong_unary3 = '~(a if b else c)'
 wrong_unary4 = 'not (a if b else c)'
 
-wrong_if = 'if a if b else c: ...'
+wrong_ternary1 = 'a if (b if some else c) else d'
+wrong_ternary2 = 'a if call(b if some else c) else d'
+wrong_ternary3 = 'a if b else (c if some else d)'
+wrong_ternary4 = '(a if some else b) if c else d'
+
+wrong_if1 = 'if a if b else c: ...'
+wrong_if2 = 'if call(a if b else c): ...'
+wrong_if3 = 'if attr.call(a if b else c): ...'
+wrong_if4 = 'if x := 1 if True else 2: ...'
 
 # Correct:
 
-correct_if = """
+correct_if1 = """
 if x:
     y = a if b else c
     print(a if b else c, end=a if b else c)
     d = {'key': a if b else c}
 """
 
+correct_if2 = """
+if x:
+    a if b else c
+"""
+
 correct_unary1 = '-a if b else c'
 correct_unary2 = 'a if -b else c'
 correct_unary3 = 'a if b else -c'
@@ -65,7 +82,8 @@
 
 
 @pytest.mark.parametrize('code', [
-    correct_if,
+    correct_if1,
+    correct_if2,
 
     correct_unary1,
     correct_unary2,
@@ -106,27 +124,41 @@ def test_non_nested_ternary(
     wrong_compare4,
     wrong_compare5,
     wrong_compare6,
+    wrong_binop7,
 
     wrong_boolop1,
     wrong_boolop2,
     wrong_boolop3,
     wrong_boolop4,
     wrong_boolop5,
     wrong_boolop6,
+    wrong_boolop7,
 
     wrong_binop1,
     wrong_binop2,
     wrong_binop3,
     wrong_binop4,
     wrong_binop5,
     wrong_binop6,
+    wrong_binop7,
 
     wrong_unary1,
     wrong_unary2,
     wrong_unary3,
     wrong_unary4,
 
-    wrong_if,
+    wrong_ternary1,
+    wrong_ternary2,
+    wrong_ternary3,
+    wrong_ternary4,
+
+    wrong_if1,
+    wrong_if2,
+    wrong_if3,
+    pytest.param(
+        wrong_if3,
+        marks=pytest.mark.skipif(not PY38, reason='walrus appeared in 3.8'),
+    ),
 ])
 def test_nested_ternary(
     assert_errors,

wemake_python_styleguide/logic/walk.py

@@ -39,17 +39,6 @@ def get_closest_parent(
         parent = get_parent(parent)
 
 
-def is_child_of(node: ast.AST, parents: _IsInstanceContainer) -> bool:
-    """
-    Checks whether node is inside a given set of parents or not.
-
-    Goes up by the tree of ``node`` to check all parents.
-    Works with general types.
-    """
-    closest_parent = get_closest_parent(node, parents)
-    return closest_parent is not None
-
-
 def is_contained_by(node: ast.AST, container: ast.AST) -> bool:
     """
     Tells you if a node is contained by a given node.

wemake_python_styleguide/visitors/ast/compares.py

@@ -7,7 +7,7 @@
 
 from wemake_python_styleguide.compat.aliases import AssignNodes
 from wemake_python_styleguide.compat.functions import get_assign_targets
-from wemake_python_styleguide.logic import nodes, source
+from wemake_python_styleguide.logic import nodes, source, walk
 from wemake_python_styleguide.logic.naming.name_nodes import is_same_variable
 from wemake_python_styleguide.logic.tree import (
     compares,
@@ -297,7 +297,7 @@ class WrongConditionalVisitor(BaseNodeVisitor):
     )
 
     _forbidden_expression_parents: ClassVar[AnyNodes] = (
-        ast.If,
+        ast.IfExp,
         ast.BoolOp,
         ast.BinOp,
         ast.UnaryOp,
@@ -318,15 +318,15 @@ def visit_any_if(self, node: AnyIf) -> None:
             self._check_simplifiable_if(node)
         else:
             self._check_simplifiable_ifexpr(node)
-            self._check_nested_ifexpr(node)
 
+        self._check_nested_ifexpr(node)
         self._check_constant_condition(node)
         self.generic_visit(node)
 
     def _is_simplifiable_assign(
         self,
         node_body: List[ast.stmt],
-    ) -> Optional[str]:
+    ) -> Optional[str]:  # TODO: move to logic at some point
         wrong_length = len(node_body) != 1
         if wrong_length or not isinstance(node_body[0], AssignNodes):
             return None
@@ -363,9 +363,16 @@ def _check_simplifiable_ifexpr(self, node: ast.IfExp) -> None:
         if conditions == {True, False}:
             self.add_violation(SimplifiableIfViolation(node))
 
-    def _check_nested_ifexpr(self, node: ast.IfExp) -> None:
-        parent = nodes.get_parent(node)
-        if isinstance(parent, self._forbidden_expression_parents):
+    def _check_nested_ifexpr(self, node: AnyIf) -> None:
+        is_nested_in_if = bool(
+            isinstance(node, ast.If) and
+            list(walk.get_subnodes_by_type(node.test, ast.IfExp)),
+        )
+        is_nested_poorly = walk.get_closest_parent(
+            node, self._forbidden_expression_parents,
+        )
+
+        if is_nested_in_if or is_nested_poorly:
             self.add_violation(NestedTernaryViolation(node))
 
 

wemake_python_styleguide/visitors/ast/complexity/nested.py

@@ -7,7 +7,7 @@
 from wemake_python_styleguide.compat.aliases import FunctionNodes
 from wemake_python_styleguide.constants import NESTED_FUNCTIONS_WHITELIST
 from wemake_python_styleguide.logic.nodes import get_context, get_parent
-from wemake_python_styleguide.logic.walk import is_child_of
+from wemake_python_styleguide.logic.walk import get_closest_parent
 from wemake_python_styleguide.types import AnyFunctionDef
 from wemake_python_styleguide.violations.best_practices import (
     NestedClassViolation,
@@ -93,7 +93,7 @@ def _check_nested_classes(self, node: ast.ClassDef) -> None:
 
     def _check_nested_lambdas(self, node: ast.Lambda) -> None:
         is_direct = isinstance(get_context(node), ast.Lambda)
-        is_deep = is_child_of(node, ast.Lambda)
+        is_deep = get_closest_parent(node, ast.Lambda)
 
         if is_direct or is_deep:
             self.add_violation(NestedFunctionViolation(node, text='lambda'))