@paroj thank you for contribution! Can you add a simple test for added scenario? It can be done as an additional method in the class Bindings located in the modules/python/test/test_misc.py.
For testing purpose you can add this simple function to modules/core/include/opencv2/core/bindings_utils.hpp

CV_WRAP static inline
void testRaiseGeneralException()
{
    throw std::exception("exception text");
}

and catch raised exception in Python using the following pattern:

with self.assertRaises((cv.error,),
                       msg='C++ exception is not propagated to Python in the right way') as cm:
    cv.utils.testRaiseGeneralException()
self.assertEqual(cm.exception.message, 'exception text')

Apart from that, maybe catch (...) statement should be added too, because C++ allows to throw anything?

@VadimLevin copy pasted the tests as desired. Are you aware that you can push to my PRs if you have maintainer access?

Apart from that, maybe catch (...) statement should be added too, because C++ allows to throw anything?

we would not be able to report anything useful in this case. Also ERRWRAP2 is added to every single function invocation in OpenCV and thus affects compile time - I already felt bad about making it longer. Therefore I would rather wait for evidence that this is needed..

catch(...)

ERRWRAP2() macro is not enough for that.
Perhaps this should be done on generator level to keep binding functions exception-free (not in scope of this PR). Possible error message is "Internal error in OpenCV Python bindings". It is much better that crash of Python runtime.