Reproduced by full-keyboard fuzz (every WM_CHAR + WM_KEYUP posted to the
game window, per-key liveness; delivery proven by the new BT_KEY_LOG
[keych] trace). Two distinct issues:
1) '&' == Shift+7 is the engine's dev-console STOP-MISSION keystroke --
one shifted-key slip while hunting unmapped panel keys (MAP zoom '+'
is Shift+'=') instantly ended the session, indistinguishable from a
crash. Now env-gated (APP.cpp): default ignored with a log line;
BT_KEY_STOP=1 restores the authentic stop (verified both ways live).
Same hazard class as the arrow-release '&' alias already swallowed in
L4CTRL.cpp:1516.
2) '\' (the developer fake-event key) was a REAL wild-jump crash:
Entity::Dispatch STAMPS entityID/interestZoneID into the message at
Entity::Message offsets (ENTITY.cpp:236), and the '\' case dispatched
a bare Receiver-sized ReceiverDataMessageOf<ControlsButton> at the
Mech -- the stamp wrote past the stack object and corrupted the frame
(cdb: call to eip=1 out of Receiver::Receive). The 1995 binary does
the identical overwrite and survived on stack-layout luck. Fixed with
Entity::Message-sized placement-new backing (btl4mppr.cpp); the only
such call site (grep-verified).
Verified: full fuzz (95 chars + F-keys + letter/digit keyups, 118 keys
delivered) survives end-to-end; '&' stops cleanly under BT_KEY_STOP=1.
KB: reconstruction-gotchas.md gains gotcha 19 (Entity::Dispatch message
stamping) + the '&' note.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
