abi.rs's two send-input entry points built &InputEvent straight out of
caller memory with ev.as_ref(); InputKind is repr(u8) with 16 valid
discriminants, so a C embedder writing ev->kind = 42 was immediate UB the
moment the reference formed — in a file whose stated principle is that
failures become status codes. New read_input_event() checks null, reads
the tag as a raw byte, validates through the same InputKind::from_u8 the
wire path uses, and only then forms the reference; bad tags return
InvalidArg. Every other field is a plain integer, valid for any pattern.
Test stages the event in MaybeUninit storage so the test itself never
holds a reference to the invalid value. 380 lib tests + the C harness
round-trip + clippy -D warnings green on .25; header regenerated.
enricobuehler
9a59504ba4