Implement extended tuple TopologyKey equality and make equality testi…

…ng more robust

openff/interchange/models.py

@@ -45,11 +45,20 @@ class TopologyKey(_BaseModel, abc.ABC):
         description="The indices of the atoms occupied by this interaction",
     )
 
+    def _tuple(self) -> tuple[Any, ...]:
+        """Tuple representation of this key."""
+        return tuple(self.atom_indices)
+
     def __hash__(self) -> int:
-        return hash(tuple(self.atom_indices))
+        return hash(self._tuple())
 
     def __eq__(self, other: Any) -> bool:
-        return self.__hash__() == other.__hash__()
+        if isinstance(other, tuple):
+            return self._tuple() == other
+        elif isinstance(other, TopologyKey):
+            return self._tuple() == other._tuple()
+        else:
+            return NotImplemented
 
     def __repr__(self) -> str:
         return f"{self.__class__.__name__} with atom indices {self.atom_indices}"
@@ -73,16 +82,11 @@ class BondKey(TopologyKey):
         ),
     )
 
-    def __hash__(self) -> int:
+    def _tuple(self) -> tuple[int, ...] | tuple[tuple[int, ...], float]:
         if self.bond_order is None:
-            return hash(tuple(self.atom_indices))
+            return tuple(self.atom_indices)
         else:
-            return hash((tuple(self.atom_indices), self.bond_order))
-
-    def __eq__(self, other) -> bool:
-        return super().__eq__(other) or (
-            self.bond_order is None and other == self.atom_indices
-        )
+            return (tuple(self.atom_indices), float(self.bond_order))
 
     def __repr__(self) -> str:
         return (
@@ -100,11 +104,8 @@ class AngleKey(TopologyKey):
         description="The indices of the atoms occupied by this interaction",
     )
 
-    def __hash__(self) -> int:
-        return hash(tuple(self.atom_indices))
-
-    def __eq__(self, other) -> bool:
-        return super().__eq__(other) or other == self.atom_indices
+    def _tuple(self) -> tuple[int, ...]:
+        return tuple(self.atom_indices)
 
 
 class ProperTorsionKey(TopologyKey):
@@ -137,18 +138,22 @@ class ProperTorsionKey(TopologyKey):
         ),
     )
 
-    def __hash__(self) -> int:
-        if self.mult is None and self.bond_order is None and self.phase is None:
-            return hash(tuple(self.atom_indices))
-        return hash((tuple(self.atom_indices), self.mult, self.bond_order, self.phase))
-
-    def __eq__(self, other) -> bool:
-        return super().__eq__(other) or (
-            self.mult is None
-            and self.bond_order is None
-            and self.phase is None
-            and other == tuple(self.atom_indices)
-        )
+    def _tuple(
+        self,
+    ) -> (
+        tuple[()]
+        | tuple[int, int, int, int]
+        | tuple[
+            tuple[int, int, int, int] | tuple[()],
+            int | None,
+            float | None,
+            float | None,
+        ]
+    ):
+        if self.mult is None and self.phase is None and self.bond_order is None:
+            return tuple(self.atom_indices)
+        else:
+            return (tuple(self.atom_indices), self.mult, self.phase, self.bond_order)
 
     def __repr__(self) -> str:
         return (
@@ -248,14 +253,12 @@ class VirtualSiteKey(TopologyKey):
         description="The `match` attribute of the associated virtual site type",
     )
 
-    def __hash__(self) -> int:
-        return hash(
-            (
-                self.orientation_atom_indices,
-                self.name,
-                self.type,
-                self.match,
-            ),
+    def _tuple(self) -> tuple[tuple[int, ...], str, str, str]:
+        return (
+            self.orientation_atom_indices,
+            self.name,
+            self.type,
+            self.match,
         )