>   str(memoryview(b'character buffers are decoded to unicode'), 'utf-8')
> I tried another patch, but I'm not sure: I get lost between all these
> buffers... a Py_DECREF(self->view.obj) in memory_releasebuf() seems to work.

Could you open a separate issue for the latter? Adding a DECREF in
memory_releasebuf() isn't the right thing to do, because PyBuffer_Release()
already does such a DECREF. I think the problem is rather in memory_getbuf(), it
tries to take some strange shortcuts.

Oh, and I realize that memoryobject doesn't have tp_traverse and tp_clear, which
looks quite wrong...