Fix a false positive with user-defined Enum class (#1967)

Co-authored-by: Daniël van Noord <[email protected]>
(cherry picked from commit c267397)

Author: mbyrnepr2

.github/workflows/ci.yaml

@@ -93,6 +93,7 @@ jobs:
       - name: Install Qt
         if: ${{ matrix.python-version == '3.10' }}
         run: |
+          sudo apt-get update
           sudo apt-get install build-essential libgl1-mesa-dev
       - name: Generate partial Python venv restore key
         id: generate-python-key

ChangeLog

@@ -16,6 +16,11 @@ Release date: TBA
 
   Closes #1958
 
+* Fix a false positive when an attribute named ``Enum`` was confused with ``enum.Enum``.
+  Calls to ``Enum`` are now inferred & the qualified name is checked.
+
+  Refs PyCQA/pylint#5719
+
 * Remove unnecessary typing_extensions dependency on Python 3.11 and newer
 
 What's New in astroid 2.13.2?

astroid/brain/brain_namedtuple_enum.py

@@ -8,6 +8,7 @@
 
 import functools
 import keyword
+import sys
 from collections.abc import Iterator
 from textwrap import dedent
 
@@ -24,7 +25,12 @@
 )
 from astroid.manager import AstroidManager
 
-TYPING_NAMEDTUPLE_BASENAMES = {"NamedTuple", "typing.NamedTuple"}
+if sys.version_info >= (3, 8):
+    from typing import Final
+else:
+    from typing_extensions import Final
+
+
 ENUM_BASE_NAMES = {
     "Enum",
     "IntEnum",
@@ -33,6 +39,8 @@
     "IntFlag",
     "enum.IntFlag",
 }
+ENUM_QNAME: Final[str] = "enum.Enum"
+TYPING_NAMEDTUPLE_BASENAMES: Final[set[str]] = {"NamedTuple", "typing.NamedTuple"}
 
 
 def _infer_first(node, context):
@@ -298,6 +306,18 @@ def infer_enum(
     node: nodes.Call, context: InferenceContext | None = None
 ) -> Iterator[bases.Instance]:
     """Specific inference function for enum Call node."""
+    # Raise `UseInferenceDefault` if `node` is a call to a a user-defined Enum.
+    try:
+        inferred = node.func.infer(context)
+    except (InferenceError, StopIteration) as exc:
+        raise UseInferenceDefault from exc
+
+    if not any(
+        isinstance(item, nodes.ClassDef) and item.qname() == ENUM_QNAME
+        for item in inferred
+    ):
+        raise UseInferenceDefault
+
     enum_meta = _extract_single_node(
         """
     class EnumMeta(object):

tests/unittest_brain.py

@@ -1230,6 +1230,50 @@ class MyEnum(PyEnum):
         assert isinstance(inferred, bases.Instance)
         assert inferred._proxied.name == "ENUM_KEY"
 
+    def test_class_named_enum(self) -> None:
+        """Test that the user-defined class named `Enum` is not inferred as `enum.Enum`"""
+        astroid.extract_node(
+            """
+        class Enum:
+            def __init__(self, one, two):
+                self.one = one
+                self.two = two
+            def pear(self):
+                ...
+        """,
+            "module_with_class_named_enum",
+        )
+
+        attribute_nodes = astroid.extract_node(
+            """
+        import module_with_class_named_enum
+        module_with_class_named_enum.Enum("apple", "orange") #@
+        typo_module_with_class_named_enum.Enum("apple", "orange") #@
+        """
+        )
+
+        name_nodes = astroid.extract_node(
+            """
+        from module_with_class_named_enum import Enum
+        Enum("apple", "orange") #@
+        TypoEnum("apple", "orange") #@
+        """
+        )
+
+        # Test that both of the successfully inferred `Name` & `Attribute`
+        # nodes refer to the user-defined Enum class.
+        for inferred in (attribute_nodes[0].inferred()[0], name_nodes[0].inferred()[0]):
+            assert isinstance(inferred, astroid.Instance)
+            assert inferred.name == "Enum"
+            assert inferred.qname() == "module_with_class_named_enum.Enum"
+            assert "pear" in inferred.locals
+
+        # Test that an `InferenceError` is raised when an attempt is made to
+        # infer a `Name` or `Attribute` node & they cannot be found.
+        for node in (attribute_nodes[1], name_nodes[1]):
+            with pytest.raises(InferenceError):
+                node.inferred()
+
 
 @unittest.skipUnless(HAS_DATEUTIL, "This test requires the dateutil library.")
 class DateutilBrainTest(unittest.TestCase):