From 3e4453ae1fcd43fd85bc6902d4cff2b5f8c6906c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Frieder=20Sch=C3=BCler?= <frieder.schueler@bizerba.com>
Date: Wed, 29 Apr 2026 20:23:17 +0200
Subject: [PATCH] Fix __contains__ and __eq__ override signatures

Change method signatures to accept 'object' as required by the
Liskov substitution principle (Mapping/Container/object supertypes).

For __eq__, return NotImplemented for incompatible types instead of
raising AttributeError. For __contains__ in SdoArray, add isinstance
check to handle non-int arguments gracefully.
---
 canopen/objectdictionary/__init__.py | 16 +++++++++++-----
 canopen/sdo/base.py                  |  8 +++++---
 test/test_od.py                      | 18 ++++++++++++++++++
 test/test_sdo.py                     |  6 ++++++
 4 files changed, 40 insertions(+), 8 deletions(-)

diff --git a/canopen/objectdictionary/__init__.py b/canopen/objectdictionary/__init__.py
index fa694c56..96e01708 100644
--- a/canopen/objectdictionary/__init__.py
+++ b/canopen/objectdictionary/__init__.py
@@ -160,7 +160,7 @@ def __iter__(self) -> Iterator[int]:
     def __len__(self) -> int:
         return len(self.indices)
 
-    def __contains__(self, index: Union[int, str]):
+    def __contains__(self, index: object) -> bool:
         return index in self.names or index in self.indices
 
     def add_object(self, obj: Union[ODArray, ODRecord, ODVariable]) -> None:
@@ -234,10 +234,12 @@ def __len__(self) -> int:
     def __iter__(self) -> Iterator[int]:
         return iter(sorted(self.subindices))
 
-    def __contains__(self, subindex: Union[int, str]) -> bool:
+    def __contains__(self, subindex: object) -> bool:
         return subindex in self.names or subindex in self.subindices
 
-    def __eq__(self, other: ODRecord) -> bool:
+    def __eq__(self, other: object) -> bool:
+        if not isinstance(other, ODRecord):
+            return NotImplemented
         return self.index == other.index
 
     def add_member(self, variable: ODVariable) -> None:
@@ -298,7 +300,9 @@ def __len__(self) -> int:
     def __iter__(self) -> Iterator[int]:
         return iter(sorted(self.subindices))
 
-    def __eq__(self, other: ODArray) -> bool:
+    def __eq__(self, other: object) -> bool:
+        if not isinstance(other, ODArray):
+            return NotImplemented
         return self.index == other.index
 
     def add_member(self, variable: ODVariable) -> None:
@@ -387,7 +391,9 @@ def qualname(self) -> str:
             return f"{self.parent.name}.{self.name}"
         return self.name
 
-    def __eq__(self, other: ODVariable) -> bool:
+    def __eq__(self, other: object) -> bool:
+        if not isinstance(other, ODVariable):
+            return NotImplemented
         return (self.index == other.index and
                 self.subindex == other.subindex)
 
diff --git a/canopen/sdo/base.py b/canopen/sdo/base.py
index e4215a3a..97b0d6c5 100644
--- a/canopen/sdo/base.py
+++ b/canopen/sdo/base.py
@@ -64,7 +64,7 @@ def __iter__(self) -> Iterator[int]:
     def __len__(self) -> int:
         return len(self.od)
 
-    def __contains__(self, key: Union[int, str]) -> bool:
+    def __contains__(self, key: object) -> bool:
         return key in self.od
 
     def get_variable(
@@ -113,7 +113,7 @@ def __len__(self) -> int:
         # Skip the "highest subindex" entry, which is not part of the data
         return len(self.od) - int(0 in self.od)
 
-    def __contains__(self, subindex: Union[int, str]) -> bool:
+    def __contains__(self, subindex: object) -> bool:
         return subindex in self.od
 
 
@@ -136,7 +136,9 @@ def __iter__(self) -> Iterator[int]:
     def __len__(self) -> int:
         return self[0].raw
 
-    def __contains__(self, subindex: int) -> bool:
+    def __contains__(self, subindex: object) -> bool:
+        if not isinstance(subindex, int):
+            return False
         return 0 <= subindex <= len(self)
 
 
diff --git a/test/test_od.py b/test/test_od.py
index 9ab0e187..231a58dd 100644
--- a/test/test_od.py
+++ b/test/test_od.py
@@ -276,5 +276,23 @@ def test_subindexes(self):
         self.assertEqual(array[3].name, "Test Variable_3")
 
 
+class TestEquality(unittest.TestCase):
+
+    def test_record_eq_wrong_type(self):
+        record = od.ODRecord("Test Record", 0x1001)
+        self.assertNotEqual(record, "not a record")
+        self.assertNotEqual(record, 42)
+
+    def test_array_eq_wrong_type(self):
+        array = od.ODArray("Test Array", 0x1002)
+        self.assertNotEqual(array, "not an array")
+        self.assertNotEqual(array, 42)
+
+    def test_variable_eq_wrong_type(self):
+        var = od.ODVariable("Test Variable", 0x1000, 0)
+        self.assertNotEqual(var, "not a variable")
+        self.assertNotEqual(var, 42)
+
+
 if __name__ == "__main__":
     unittest.main()
diff --git a/test/test_sdo.py b/test/test_sdo.py
index 9764a6d3..a9418716 100644
--- a/test/test_sdo.py
+++ b/test/test_sdo.py
@@ -48,6 +48,12 @@ def test_array_members_dynamic(self):
         for var in array.values():
             self.assertIsInstance(var, canopen.sdo.SdoVariable)
 
+    def test_array_contains_non_int(self):
+        """SdoArray.__contains__ should handle non-int types gracefully."""
+        array = self.sdo_node[0x1003]
+        self.assertNotIn("not an int", array)
+        self.assertNotIn(None, array)
+
 
 class TestSDO(unittest.TestCase):
     """