My perspective is that hashing a memoryview only makes sense when the memoryview is read-only and "m == m.tobytes()" (i.e. it's a C contiguous 1D view of bytes, either because that's what the original object exported as a buffer or because the view has been cast that way)

So, I think we should document that restriction in What's New and the memoryview docs for 3.3.0, and actually enforce it in 3.3.1 by raising ValueError from hash(m) when the assumption of a 1D C contiguous bytes view is violated (the "read-only" restriction is already enforced).

In previous versions, this constraint didn't need to be explicitly enforced, since memoryview basically treated *everything* as a 1D C contiguous view of bytes.