This is a follow-up to the discussion in gh-191. It's a recommendation rather than a hard requirement to allow implementers some choice. That said, this is how things worked in practice before DLPack 1.0 as well, since there was no flag to represent read-only. Experience with JAX showed that exposing shared memory was preferred by users over raising or always making a copy of the data on the producer side.
This is a follow-up to the discussion in gh-191. It's a recommendation rather than a hard requirement to allow implementers some choice. That said, this is how things worked in practice before DLPack 1.0 as well, since there was no flag to represent read-only. Experience with JAX showed that exposing shared memory was preferred by users over raising or always making a copy of the data on the producer side.