Two corrections to Q#LL8, both found by review of 1c9ff6a, and both the
same shape: a fix that read as complete because it was correct in one
of two places.
The GPU has its own scroll indicator. format_scroll_indicator is
DUPLICATED, not shared --- src/editor.rs:5509 and
pmacs-gpu/src/main.rs:10114, each with its own tests --- and the GPU
passes current_line_starts.len(), a source-line count. So revision 15
would have fixed the indicator in the TUI and left the GPU reporting
"All" for a one-line wrapped buffer.
That is worth naming plainly: it is this lane's own defect, reproduced
inside the section written to close it. The lane exists because two
frontends disagree for reasons nobody chose, and the fix disagreed for
exactly that reason one more time.
Both copies keep their signature. The formatter is a pure function over
counts and is correct as written; what changes is what the callers
pass --- visual rows rather than source lines, visible rows rather than
visible lines. Every existing formatter test stays valid, including the
GPU's own format_scroll_indicator(0, 10, 1, 0) == "All", which pins
line-space behavior and must not silently change meaning.
The lazy total's cache key omitted fold state. Folds are built per
rendered window and can be collapsed or expanded with no edit, no
resize and no mode change --- so all three of revision 15's key
components sit still while the projection underneath them moves. Cache
NN%, toggle a fold, and the stale total is served for the new
projection.
Now keyed on (buffer generation, content width, mode, fold projection),
and specifically on the projection's own components rather than a
revision counter on the fold registry. Components is one entry per
collapsed region, so comparing it is O(folds), and the key IS the thing
it guards --- it cannot be forgotten. A maintained counter can, on
every present and future mutation path, which is the same
did-you-remember hazard as LL7's buffer-switch trigger. Same principle
as byte-anchoring over a row index and additive sub_row over redefining
row: self-validating beats maintained.
Content width, not window width. Wrapping happens in the text area, and
the gutter's width changes at the line-count digit boundary (9 -> 10,
99 -> 100) --- something the GPU's sync_buffer_dimensions comment
already records for its own shaping. Keying on window width would serve
a stale total across that boundary.
Three witnesses added: the reported case in BOTH frontends, a "cache,
then toggle a fold" case that fails against revision 15's key, and a
digit-boundary case.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016bqGA6s9tTUFzYpbeW3tai
Levi Neuwirth
b95506f6ca