Merge pull request #3044 from HypothesisWorks/sobolevn-patch-1

Changes how we treat newtypes
HypothesisWorks · Jul 27, 2021 · 9d7d515 · 9d7d515
2 parents 87f9f75 + 6b758e0
commit 9d7d515
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diff --git a/hypothesis-python/RELEASE.rst b/hypothesis-python/RELEASE.rst
@@ -0,0 +1,4 @@
+RELEASE_TYPE: patch
+
+This patch fixes ``hypothesis.strategies._internal.types.is_a_new_type``.
+It was failing on Python ``3.10.0b4``, where ``NewType`` is a function.
diff --git a/hypothesis-python/src/hypothesis/strategies/_internal/types.py b/hypothesis-python/src/hypothesis/strategies/_internal/types.py
@@ -98,7 +98,7 @@ def try_issubclass(thing, superclass):
 
 
 def is_a_new_type(thing):
-    if sys.version_info[:2] < (3, 10):
+    if not isinstance(typing.NewType, type):
         # At runtime, `typing.NewType` returns an identity function rather
         # than an actual type, but we can check whether that thing matches.
         return (