Keep hash consistent for enum in newer Python versions (#189)

Fix #188

sisyphus/hash.py

@@ -1,3 +1,4 @@
+import enum
 import hashlib
 from inspect import isclass, isfunction
 
@@ -61,6 +62,11 @@ def get_object_state(obj):
         assert args is not None, "Failed to get object state of: %s" % repr(obj)
         state = None
 
+    if isinstance(obj, enum.Enum):
+        assert isinstance(state, dict)
+        # In Python >=3.11, keep hash same as in Python <=3.10, https://github.com/rwth-i6/sisyphus/issues/188
+        state.pop("_sort_order_", None)
+
     if args is None:
         return state
     else:
@@ -76,7 +82,7 @@ def sis_hash_helper(obj):
     """
 
     # Store type to ensure it's unique
-    byte_list = [type(obj).__qualname__.encode()]
+    byte_list = [_obj_type_qualname(obj)]
 
     # Using type and not isinstance to avoid derived types
     if isinstance(obj, bytes):
@@ -116,3 +122,10 @@ def sis_hash_helper(obj):
         return hashlib.sha256(byte_str).digest()
     else:
         return byte_str
+
+
+def _obj_type_qualname(obj) -> bytes:
+    if type(obj) is enum.EnumMeta:  # EnumMeta is old alias for EnumType
+        # In Python >=3.11, keep hash same as in Python <=3.10, https://github.com/rwth-i6/sisyphus/issues/188
+        return b"EnumMeta"
+    return type(obj).__qualname__.encode()

tests/hash_unittest.py

@@ -7,6 +7,11 @@ def b():
     pass
 
 
+class MyEnum(enum.Enum):
+    Entry0 = 0
+    Entry1 = 1
+
+
 class HashTest(unittest.TestCase):
     def test_get_object_state(self):
 
@@ -18,6 +23,15 @@ def d():
         self.assertEqual(sis_hash_helper(b), b"(function, (tuple, (str, '" + __name__.encode() + b"'), (str, 'b')))")
         self.assertRaises(AssertionError, sis_hash_helper, c)
 
+    def test_enum(self):
+        self.assertEqual(
+            sis_hash_helper(MyEnum.Entry1),
+            b"(%s, (dict, (tuple, (str, '__objclass__')," % MyEnum.__name__.encode()
+            + b" (EnumMeta, (tuple, (str, '%s'), (str, '%s')))),"
+            % (MyEnum.__module__.encode(), MyEnum.__name__.encode())
+            + b" (tuple, (str, '_name_'), (str, 'Entry1')), (tuple, (str, '_value_'), (int, 1))))",
+        )
+
 
 if __name__ == "__main__":
     unittest.main()