Update News. Add tests for Literal.__args__

python · miss-islington · Nov 17, 2020 · Nov 15, 2020 · Nov 15, 2020 · Nov 15, 2020
commit f653d680e2fbf94e254f32a8a7e24cb0f95369a9
diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py
@@ -569,10 +569,20 @@ def test_equal(self):
        self.assertEqual(Literal[1, 2], Literal[2, 1])
        self.assertEqual(Literal[1, 2, 3], Literal[1, 2, 3, 3])

+    def test_args(self):
+        self.assertEqual(Literal[1, 2, 3].__args__, (1, 2, 3))
+        self.assertEqual(Literal[1, 2, 3, 3].__args__, (1, 2, 3))
+        self.assertEqual(Literal[1, Literal[2], Literal[3, 4]].__args__, (1, 2, 3, 4))
+        # Mutable arguments will not be deduplicated
+        self.assertEqual(Literal[[], []].__args__, ([], []))
+
    def test_flatten(self):
-        self.assertEqual(Literal[Literal[1], Literal[2], Literal[3]], Literal[1, 2, 3])
-        self.assertEqual(Literal[Literal[1, 2], 3], Literal[1, 2, 3])
-        self.assertEqual(Literal[Literal[1, 2, 3]], Literal[1, 2, 3])
+        l1 = Literal[Literal[1], Literal[2], Literal[3]]
+        l2 = Literal[Literal[1, 2], 3]
+        l3 = Literal[Literal[1, 2, 3]]
+        for l in l1, l2, l3:
+            self.assertEqual(l, Literal[1, 2, 3])
+            self.assertEqual(l.__args__, (1, 2, 3))


 XK = TypeVar('XK', str, bytes)

diff --git a/Lib/typing.py b/Lib/typing.py
@@ -251,9 +251,6 @@ def _tp_cache(func=None, /, *, typed=False):
    """Internal wrapper caching __getitem__ of generic types with a fallback to
    original function for non-hashable arguments.
    """
-    if func is not None:
-        return _tp_cache(typed=typed)(func)
-
    def decorator(func):
        cached = functools.lru_cache(typed=typed)(func)
        _cleanups.append(cached.cache_clear)
@@ -267,6 +264,9 @@ def inner(*args, **kwds):
            return func(*args, **kwds)
        return inner

+    if func is not None:
+        return decorator(func)
+
    return decorator

 def _eval_type(t, globalns, localns, recursive_guard=frozenset()):

diff --git a/Misc/NEWS.d/next/Library/2020-11-15-15-23-34.bpo-42345.hiIR7x.rst b/Misc/NEWS.d/next/Library/2020-11-15-15-23-34.bpo-42345.hiIR7x.rst
@@ -1,4 +1,2 @@
-Fix ``typing.Literal`` equals method to ignore the order of arguments.
-Fix issue related to ``typing.Literal`` caching by adding ``typed``
-parameter to ``typing._tp_cache`` function. Add deduplication of
-``typing.Literal`` arguments. Patch provided by Yurii Karabas.
+Fix various issues with ``typing.Literal`` parameter handling (flatten,
+deduplicate, use type to cache key). Patch provided by Yurii Karabas.