Revert OrderedDict key ordering in Dict space (#1291)

gymnasium/spaces/dict.py

@@ -4,6 +4,7 @@
 
 import collections.abc
 import typing
+from collections import OrderedDict
 from typing import Any, KeysView, Sequence
 
 import numpy as np
@@ -66,8 +67,9 @@ def __init__(
             seed: Optionally, you can use this argument to seed the RNGs of the spaces that make up the :class:`Dict` space.
             **spaces_kwargs: If ``spaces`` is ``None``, you need to pass the constituent spaces as keyword arguments, as described above.
         """
-        # Convert the spaces into an OrderedDict
-        if isinstance(spaces, collections.abc.Mapping):
+        if isinstance(spaces, OrderedDict):
+            spaces = dict(spaces.items())
+        elif isinstance(spaces, collections.abc.Mapping):
             # for legacy reasons, we need to preserve the sorted dictionary items.
             # as this could matter for projects flatten the dictionary.
             try:

tests/spaces/test_dict.py

@@ -37,8 +37,22 @@ def test_dict_init():
         assert a == b == c == d
     assert len(caught_warnings) == 0
 
+    # test sorting
     with warnings.catch_warnings(record=True) as caught_warnings:
-        Dict({1: Discrete(2), "a": Discrete(3)})
+        # Sorting is applied to the keys
+        a = Dict({"b": Box(low=0.0, high=1.0), "a": Discrete(2)})
+        assert a.keys() == {"a", "b"}
+
+        # Sorting is not applied to the keys
+        b = Dict(OrderedDict(b=Box(low=0.0, high=1.0), a=Discrete(2)))
+        c = Dict((("b", Box(low=0.0, high=1.0)), ("a", Discrete(2))))
+        d = Dict(b=Box(low=0.0, high=1.0), a=Discrete(2))
+        assert b.keys() == c.keys() == d.keys() == {"b", "a"}
+    assert len(caught_warnings) == 0
+
+    # test sorting with different classes
+    with warnings.catch_warnings(record=True) as caught_warnings:
+        assert Dict({1: Discrete(2), "a": Discrete(3)}).keys() == {1, "a"}
     assert len(caught_warnings) == 0