Share one fixed eight-column tab-stop contract across core and GPU renderers. Consolidate byte-to-display-column accounting, expand GPU code tabs with source provenance, align caret/hit/decoration geometry, and refresh minimap projection on edits.
Sub-arc 2 of the UX arc, TUI half. When a window reserves a line-number
gutter, lines with diagnostics get a severity-colored sign glyph (E/W/I/H)
in the gutter's leading column — closing the last deferred Task #23 item.
No protocol/daemon change: the per-line severity is already frontend-side
(the diag store the DiagnosticView already reads).
- `Viewport` gains `gutter_w` so overlays can reach the gutter's leading
column at `cell_origin.col - gutter_w`; the text area is already shifted
past it, so viewport-relative painters stay gutter-agnostic.
- The gutter's number pass now runs *before* the overlays (was after), so
the DiagnosticView can draw its sign into the gutter's blanked leading
column without the number pass erasing it.
- DiagnosticView: with a gutter, draw the severity sign glyph colored by
`underline_color()`; without one, keep the legacy column-0 background
marker (the "fake gutter" that predates a real gutter column). Extracted
to `paint_line_markers` to keep `render` under the line cap.
The number never reaches column 0 (>=1 leading pad by construction), so
sign and number coexist. Diagnostic signs currently ride the line-number
gutter (visible when line numbers are on); a signs-without-numbers mode is
deferred.
Test: gutter_sign_replaces_the_column_marker_when_a_gutter_is_reserved.
Validated: fmt + clippy --all-targets clean both flavors; 1441 lib + 22
diag tests pass. Needs a TUI eyeball before the GPU half.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014TXbAwk27agwhrNNrhLi2U
The GPU frontend's per-keystroke edits arrive as FrontendEvent::CrdtOp.
The old apply path materialized the whole document and diffed it per
op — O(file) per typed character on the daemon main thread.
- CrdtState: persistent text-projection subscription (capture gated by
an AtomicBool so per-keystroke imports don't register/drop
callbacks); import_updates_with_text_deltas returns Loro's deltas;
unicode_to_utf8_pos converts the insert point.
- Buffer::apply_remote_crdt_op: the common single-insert delta applies
straight to the rope; deletes/compound updates keep the conservative
materialize+diff fallback. UTF-8 position regression test included.
- SyntaxRegistry::has_pending_parse_job_for: the main-thread
"parse in flight" bit render producers need for settle-gating.
- TextView::pos_to_display: stack buffer for short line prefixes +
valid_up_to() boundary trim — removes a per-cursor-move allocation.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>