When passing u64, u32, u16 or u8 values between rust and python the runtime incorrectly handles them as the equivalent signed type which leads to overflows for extreme values. This change adds explicit handling for unsigned types.
I believe this wasn't being caught by the existing tests because the overflow was symmetric in each direction so values would overflow when passed from rust->python and then overflow again when passed in the opposite direction, returning to the initial value. Since the only check being done was that the value returned from the round trip unchanged the tests did not see this happening. This change adds a check in the python guest code which asserts that values which are expected to be unsigned are actually non-negative.
When passing u64, u32, u16 or u8 values between rust and python the runtime incorrectly handles them as the equivalent signed type which leads to overflows for extreme values. This change adds explicit handling for unsigned types.
I believe this wasn't being caught by the existing tests because the overflow was symmetric in each direction so values would overflow when passed from rust->python and then overflow again when passed in the opposite direction, returning to the initial value. Since the only check being done was that the value returned from the round trip unchanged the tests did not see this happening. This change adds a check in the python guest code which asserts that values which are expected to be unsigned are actually non-negative.
fixes #125