Symbolized (HOIST_KEEP_NAMES=1): the trap is on the asyncify REWIND re-entering
the fiber — stack-local COROUTINE+body were destroyed when Call() returned
early on a park, so the rewind called through freed objects (latent UB in the
ORIGINAL fire-and-forget runOnFiber too). Heap-pinned FiberSlot + explicit
done flag + fiber-tail re-drain. Layer 2 (rewind interplay) still open —
fuzz stays fixme'd; pageerror stacks now captured in fuzz artifacts.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01G5cAM9M6q34n5X4dbrfVvi
drift-trio-fuzz.spec.ts: mulberry32-seeded weighted concurrent actions on A+B
(C observes), K=40, marker-synced oracle sweep every 10 steps, per-tab console
capture, and a replayable failure artifact (seed + action log + drift/saves/
renders/consoles) dumped to logs/kicad/drift-trio-fuzz/. DRIFT_FUZZ_SEED
replays a sequence exactly.
First catch (0008 §10 #10, OPEN): the actively-editing receiver's C++ apply
silently drops ops under sustained bidirectional load — JS dispatched every
apply, the editor never applied some; pure observer and emitter stay clean;
one run hit a wasm 'memory access out of bounds' on the observer. Timing-
dependent, so the fuzz tests are test.fixme'd (an expected-fail would flake
CI) and run manually via DRIFT_FUZZ_SEED until the fix lands (phase E).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01G5cAM9M6q34n5X4dbrfVvi
