Don't error when exception_check is set to True and return type is PyObject. (GH-4433)

With Cython syntax, we ignore the exception_check when a Python object is returned.
In pure Python mode, with a Python object type as return type, we reject it.
Instead of raising an error, we now just reset exception_check to False.

Found in https://github.com/cython/cython/issues/2529

1 files changed, 7 insertions, 0 deletions

diff --git a/tests/errors/pure_errors.py b/tests/errors/pure_errors.py
index 570dc006f..b153bd2e6 100644
--- a/tests/errors/pure_errors.py
+++ b/tests/errors/pure_errors.py
@@ -50,8 +50,15 @@ def pyfunc(x):  # invalid
     return x + 1
 
 
+@cython.exceptval(-1)
+@cython.cfunc
+def test_cdef_return_object_broken(x: object) -> object:
+    return x
+
+
 _ERRORS = """
 44:22: Calling gil-requiring function not allowed without gil
 45:24: Calling gil-requiring function not allowed without gil
 48:0: Python functions cannot be declared 'nogil'
+53:0: Exception clause not allowed for function returning Python object
 """