fix: make Permissions hashable to match User and Group (#3154)

Author: ioleksiuk

src/agents/sandbox/types.py

@@ -124,6 +124,9 @@ def __eq__(self, other: object) -> bool:
             return NotImplemented
         return self.to_mode() == other.to_mode()
 
+    def __hash__(self) -> int:
+        return hash(self.to_mode())
+
 
 class FileMode(IntEnum):
     ALL = 0o7

tests/sandbox/test_types.py

@@ -0,0 +1,22 @@
+from agents.sandbox.types import Group, Permissions, User
+
+
+def test_permissions_is_hashable() -> None:
+    # ``Permissions`` overrides ``__eq__``; without a matching ``__hash__`` Pydantic v2
+    # would set ``__hash__ = None``, breaking sets and dict keys for what is otherwise
+    # a value-like type. Sibling classes ``User`` and ``Group`` already define both.
+    perms = Permissions.from_mode(0o755)
+    other = Permissions.from_mode(0o755)
+    different = Permissions.from_mode(0o644)
+
+    assert hash(perms) == hash(other)
+    assert hash(perms) != hash(different)
+    assert {perms, other, different} == {perms, different}
+    assert {perms: "value"}[other] == "value"
+
+
+def test_user_and_group_remain_hashable() -> None:
+    # Regression guard for the sibling classes whose hashability the Permissions fix
+    # mirrors.
+    assert hash(User(name="alice")) == hash(User(name="alice"))
+    assert hash(Group(name="admin", users=[])) == hash(Group(name="admin", users=[]))