P1 — Q#HS7(c) WITHDRAWN, and my vote was wrong rather than vague.
Revision 2 voted to snap `view_left` to a valid boundary at the moment
it is set. That cannot exist. `view_left` is ONE per-window display
column, but "does column N bisect a wide glyph?" is a PER-LINE
question: column 11 can be a wide glyph's trailing cell on line 3 and
ordinary ASCII on line 4. No setter-time value is canonical for every
visible line. Snapping per line instead is worse — the same source
column would appear at different screen columns on different rows,
destroying the alignment a column-oriented view exists to provide.
Replaced by (c′), a per-line effective edge. `view_left` is stored
unsnapped; each line derives its own edge during the walk it already
performs from column 0. Where the requested edge bisects a wide glyph
on THAT line, the finding's actual question — what occupies the
leftmost cell — is answered: it paints as a space carrying the glyph's
style, and the mapping DESIGNATES that cell to the wide glyph's start
byte. That keeps `byte_at_place` total over visible cells, preserves
the round trip (`place_of_byte(start)` reports the straddle and
designates cell 0), and gives a click there the character a user would
expect. Bytes lying entirely left of the edge are reported not-visible
rather than clamped to column 0, because clamping would make
arbitrarily many bytes share cell 0 and destroy (d).
Recorded as deliberately NOT the mirror of Stage 3's right-edge rule:
under wrap a too-wide glyph is pushed to the next row entirely, and at
the left edge under truncate there is no next row, so the same intent
requires a different rule. Stated so nobody "fixes" one to match the
other.
(d) is amended accordingly: the invariant is a property of
`(view_left, line)`, not of `view_left` alone — which is what makes a
multi-line fixture with differing glyph widths at the same column the
DISCRIMINATING test rather than an extra one. A single-line sweep
passes against the withdrawn design.
P1 — Stage 4 no longer closes the arc, and the stale claim was
load-bearing in the wrong direction. Rule 4 removes a lane when its ARC
is done, so a framing asserting Stage 4 closes it would license
retiring the lane at the TUI merge — orphaning the very Stage 5 that
Q#HS1's time box exists to guarantee, while `truncate` is still a dead
end in the GUI. Both the framing opening and the lane header now say
the arc closes at Stage 5, and the lane carries an explicit "Rule 4
does not apply at Stage 4's merge".
P2 — the stale Stage 3 residue in the ledger claimed the unreachable
caveat is in the setting description, contradicting revision 2 forty
lines above it. Corrected in place: the caveat lives only in the
toggle's status message and a source comment, and a user who sets the
mode in init.lua is told nothing.
Q#HS5 now states the concrete condition rather than an instruction to
check one. Verified: SavedLeaf carries no #[serde(default)] anywhere in
src/desktop.rs, so serde would REJECT a version-1 desktop JSON omitting
a new `view_left`. "Yes, no version bump" is sound only with the
annotation AND a regression fixture holding literal v1 JSON without the
field. The reverse direction already works — an old binary meets an
unknown field, which serde ignores absent deny_unknown_fields, and
there is none in that file.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016bqGA6s9tTUFzYpbeW3tai
Levi Neuwirth
baa71b607e