The mirror of sylpheed-port's sweep after their exit_ramp_units catch, where a
refuted 24.0 survived in a `get(..., 24.0)` fallback because the authored entry
had been deleted as progress and the deletion was a no-op.
112 fallback sites across sylpheed-formats and sylpheed-cli. 64 supply 0, false,
empty or Default -- sentinels asserting nothing. Of the 48 remaining most are
pass-through or an extent. Positive control: the filter found media.rs:314
unwrap_or(anchor), the voice-region start fallback landed earlier this session,
so the detector finds a known case rather than only reporting absence. The
mesh.rs cluster (1.0, 0.85, 0.5, 0.70, 0.45) is env-var tunables with defaults
documented in xbg7-mesh.md.
ui_layout.rs, the crate the port pins, has 8 sites; 6 sentinel or pass-through
and 2 that could fabricate a quantity. Both fabricate a value that is
LEGITIMATE, which is worse than the port's conspicuous 24.0:
:695 unwrap_or((DESIGN_W, DESIGN_H)) -- 1280x720, which is what every real
screen states, so no parser output can distinguish read from invented.
MEASURED: it fires 0 times in 965 builds disc-wide, so design_w/design_h
is read and the port can rely on it.
:1681 kf.time.unwrap_or(0) in the serialiser -- 0 is a real keyframe time
(pose 0's time IS 0). Unreachable today under the corrected record
layout, the same status as their exit_ramp_units branch, but a
fabricated 0 would be indistinguishable from a real one.
The measuring instrument failed its own control first: a version reading EVERY
RATC child reported all 965 builds stating a non-standard design size
(GP_TUTORIAL 12x3), where `screen list` prints 1280x720 for every one -- a T8aD
sprite header read at +0x18 is garbage that passes the range test. Filtered to
the .rat records, it reproduces screen list exactly.
METHOD: a fallback default is an authored value no reader can see, and the
dangerous ones are IN-RANGE -- the only way to know is to count how often they
fire, which no parser output reveals.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wuu56cE8vJGTBtn1ppsk8v
61dbc5cca5