Remove default in_c_key and change for cast_policy

pytensor/configdefaults.py

@@ -258,6 +258,7 @@ def add_basic_configvars():
             # was expected, so it is currently not available.
             # numpy,
         ),
+        in_c_key=False,
     )
 
     config.add(

pytensor/configparser.py

@@ -214,9 +214,7 @@ class PyTensorConfigParser:
             )
         )
 
-    def add(
-        self, name: str, doc: str, configparam: "ConfigParam", in_c_key: bool = True
-    ):
+    def add(self, name: str, doc: str, configparam: "ConfigParam", in_c_key: bool):
         """Add a new variable to PyTensorConfigParser.
 
         This method performs some of the work of initializing `ConfigParam` instances.

tests/test_config.py

@@ -98,6 +98,7 @@ def test_config_hash():
         "test__config_hash",
         "A config var from a test case.",
         configparser.StrParam("test_default"),
+        in_c_key=True,
     )
 
     h0 = root.get_config_hash()
@@ -160,6 +161,7 @@ def test_config_context():
         "test__config_context",
         "A config var from a test case.",
         configparser.StrParam("test_default"),
+        in_c_key=False,
     )
     assert hasattr(root, "test__config_context")
     assert root.test__config_context == "test_default"
@@ -181,6 +183,7 @@ def test_invalid_configvar_access():
         "test__on_test_instance",
         "This config setting was added to the test instance.",
         configparser.IntParam(5),
+        in_c_key=False,
     )
     assert hasattr(root_test, "test__on_test_instance")
     # While the property _actually_ exists on all instances,
@@ -197,6 +200,7 @@ def test_invalid_configvar_access():
             "test__on_test_instance",
             "This config setting was already added to another instance.",
             configparser.IntParam(5),
+            in_c_key=False,
         )
 
 
@@ -248,6 +252,7 @@ def test_config_pickling():
         "test__lambda_kills_pickling",
         "Lambda functions cause pickling problems.",
         configparser.IntParam(5, lambda i: i > 0),
+        in_c_key=False,
     )
     with pytest.raises(AttributeError, match="Can't pickle local object"):
         pickle.dump(root, io.BytesIO())