Check that a name exists inside enum.Enum class' __members__. (#8905)

Refs #7402

Author: mbyrnepr2

doc/whatsnew/fragments/7402.false_positive

@@ -0,0 +1,3 @@
+Fix a false positive for ``invalid-name`` when a type-annotated class variable in an ``enum.Enum`` class has no assigned value.
+
+Refs #7402

pylint/checkers/base/name_checker/checker.py

@@ -485,15 +485,12 @@ def visit_assignname(  # pylint: disable=too-many-branches
 
         # Check names defined in class scopes
         elif isinstance(frame, nodes.ClassDef):
-            if not list(frame.local_attr_ancestors(node.name)):
-                for ancestor in frame.ancestors():
-                    if utils.is_enum(ancestor) or utils.is_assign_name_annotated_with(
-                        node, "Final"
-                    ):
-                        self._check_name("class_const", node.name, node)
-                        break
-                else:
-                    self._check_name("class_attribute", node.name, node)
+            if utils.is_enum_member(node) or utils.is_assign_name_annotated_with(
+                node, "Final"
+            ):
+                self._check_name("class_const", node.name, node)
+            else:
+                self._check_name("class_attribute", node.name, node)
 
     def _recursive_check_names(self, args: list[nodes.AssignName]) -> None:
         """Check names in a possibly recursive list <arg>."""

pylint/checkers/utils.py

@@ -2266,3 +2266,20 @@ def clear_lru_caches() -> None:
     ]
     for lru in caches_holding_node_references:
         lru.cache_clear()
+
+
+def is_enum_member(node: nodes.AssignName) -> bool:
+    """Return `True` if `node` is an Enum member (is an item of the
+    `__members__` container).
+    """
+
+    frame = node.frame()
+    if (
+        not isinstance(frame, nodes.ClassDef)
+        or not frame.is_subtype_of("enum.Enum")
+        or frame.root().qname() == "enum"
+    ):
+        return False
+
+    enum_member_objects = frame.locals.get("__members__")[0].items
+    return node.name in [name_obj.name for value, name_obj in enum_member_objects]

tests/functional/i/invalid/invalid_name/invalid_name_enum.py

@@ -0,0 +1,30 @@
+""" Tests for invalid-name checker in the context of enums. """
+# pylint: disable=too-few-public-methods
+
+
+from enum import Enum
+
+
+class Color(Enum):
+    """Represents colors as (red, green, blue) tuples."""
+
+    YELLOW      = 250, 250,   0
+    KHAKI       = 250, 250, 125
+    MAGENTA     = 250,   0, 250
+    VIOLET      = 250, 125, 250
+    CYAN        =   0, 250, 250
+    aquamarine  = 125, 250, 250  # [invalid-name]
+
+    red: int
+    green: int
+    blue: int
+
+    def __init__(self, red: int, green: int, blue: int) -> None:
+        self.red   = red
+        self.green = green
+        self.blue  = blue
+
+    @property
+    def as_hex(self) -> str:
+        """Get hex 'abcdef' representation for a color."""
+        return f'{self.red:0{2}x}{self.green:0{2}x}{self.blue:0{2}x}'

tests/functional/i/invalid/invalid_name/invalid_name_enum.txt

@@ -0,0 +1 @@
+invalid-name:16:4:16:14:Color:"Class constant name ""aquamarine"" doesn't conform to UPPER_CASE naming style":HIGH