D087 - Decoding never fails; it reports

assumed · 2026-08-19

Neither shader::decode nor gpu::packet::walk returns Result. A binary that cannot be walked is a finding, carried on the returned value.

A sweep over a corpus has to say how many binaries were strange. One that stops at the first strange binary answers a question nobody asked.

Three findings are carried, and the distinction matters:

• desynchronised - an unrecognised item of unknown length was passed, so everything after it is suspect. Coverage from such a walk is a lower bound, not a measurement.
• overran - something claimed to extend past the buffer. Following it would read unrelated memory as instructions, and it is the best single indicator that a length rule is wrong.
• trailing bytes - not a whole number of dwords, so the buffer is not what it was thought to be.

is_trustworthy exists so a caller can tell a measurement from a lower bound. A tool that cannot say when to distrust it is worse than no tool, because its numbers get quoted anyway.