fix: support empty sequence

PrettyWood · Feb 4, 2021 · 95bdc3a · 95bdc3a
1 parent 9b86ec8
commit 95bdc3a
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Showing 2 changed files with 12 additions and 0 deletions.
diff --git a/tests/test_main.py b/tests/test_main.py
@@ -98,6 +98,8 @@ def test_isinstancex_dict(obj, tp, expected):
         ([3, 4, "1", 2], List[int], False),
         ([3, 4, 1.1, 2], List[float], False),
         ((3, 4), List[int], False),
+        ([], List[Any], True),
+        ([], list, True),
     ],
 )
 def test_isinstancex_list(obj, tp, expected):
@@ -134,6 +136,9 @@ def test_isinstancex_set(obj, tp, expected):
         ((3,), Tuple[str], False),
         ((3,), Tuple[int, str], False),
         ([3], Tuple[int], False),
+        ((), Tuple[()], True),
+        ((), Tuple[Any, ...], True),
+        ((), tuple, True),
     ],
 )
 def test_isinstancex_tuple(obj, tp, expected):
@@ -350,6 +355,10 @@ def no_everything(x, y):
         (["pika", "chu"], Sequence[str], True),
         (("pika", "chu"), Sequence[str], True),
         (("pika", "chu"), Sequence[int], False),
+        ([], Sequence, True),
+        ([], Sequence[Any], True),
+        ("", Sequence, True),
+        ((), Sequence[int], True),
     ],
 )
 def test_isinstancex_sequence(obj, tp, expected):

diff --git a/typingx/main.py b/typingx/main.py
@@ -209,6 +209,9 @@ def _is_valid_sequence(obj: Any, tp: TypeLike, *, is_list: bool) -> bool:
     Check that a sequence respects a type with args like [str], [str, int], [str, ...]
     but also args like [str, int, ...] or even [str, int, ..., bool, ..., float]
     """
+    if len(obj) == 0:
+        return True
+
     expected_types = get_args(tp) or (Any, ...)
 
     # We consider expected types of `List[int]` as [int, ...]