Merge pull request #2097 from Zac-HD/fix-350

Fix typing issue under Python 3.5.0
HypothesisWorks · Sep 20, 2019 · 6f0c8fd · 6f0c8fd
2 parents 18fdf45 + f9b4a98
commit 6f0c8fd
Show file tree

Hide file tree

Showing 2 changed files with 12 additions and 5 deletions.
diff --git a/hypothesis-python/RELEASE.rst b/hypothesis-python/RELEASE.rst
@@ -0,0 +1,5 @@
+RELEASE_TYPE: patch
+
+This patch disables part of the :mod:`typing`-based inference for the
+:pypi:`attrs` package under Python 3.5.0, which has some incompatible
+internal details (:issue:`2095`).
diff --git a/hypothesis-python/src/hypothesis/internal/compat.py b/hypothesis-python/src/hypothesis/internal/compat.py
@@ -304,11 +304,13 @@ def qualname(f):
         typing_root_type = (typing._Final, typing._GenericAlias)  # type: ignore
         ForwardRef = typing.ForwardRef  # type: ignore
     except AttributeError:
-        typing_root_type = (
-            typing.TypingMeta,
-            typing.TypeVar,
-            typing._Union,
-        )  # type: ignore
+        typing_root_type = (typing.TypingMeta, typing.TypeVar)  # type: ignore
+        try:
+            typing_root_type += (typing._Union,)  # type: ignore
+        except AttributeError:
+            # Under Python 3.5.0, we'll just give up... if users want strategies
+            # inferred from Union-typed attrs attributes they can try a newer Python.
+            pass
         ForwardRef = typing._ForwardRef  # type: ignore