validation for provider_kw

Author: tybug

hypothesis-python/src/hypothesis/internal/conjecture/data.py

@@ -1614,6 +1614,12 @@ def __init__(
             observer = DataObserver()
         if provider_kw is None:
             provider_kw = {}
+        elif not isinstance(provider, type):
+            raise InvalidArgument(
+                f"Expected {provider=} to be a class since {provider_kw=} was "
+                "passed, but got an instance instead."
+            )
+
         assert isinstance(observer, DataObserver)
         self._bytes_drawn = 0
         self.observer = observer

hypothesis-python/tests/conjecture/test_alt_backend.py

@@ -595,3 +595,14 @@ def test_function(x):
         with pytest.raises(AssertionError) as ctx:
             test_function()
         assert (msg in ctx.value.__notes__) == (provider is UnsoundVerifierProvider)
+
+
+def test_invalid_provider_kw():
+    with pytest.raises(InvalidArgument, match="got an instance instead"):
+        ConjectureData(
+            max_length=0,
+            prefix=b"",
+            random=None,
+            provider=TrivialProvider(None),
+            provider_kw={"one": "two"},
+        )