Second Phase A session. pmacs-gpu now consumes
`InstanceMessage::Decorations` with the same M11.4 dirty-merge shape
as `StyleSpans`. Diagnostic kinds render as foreground color
overrides; background-needing kinds (selection, search match, current
line) accumulate in state but stay unpainted pending a quad pipeline.
What's wired
- `State.current_decorations: Vec<Decoration>`, sorted by
`range.start`, cleared on `BufferSnapshot` like `current_spans`.
- `apply_attach_message` gains a `Decorations` arm — `full=true` →
`replace_decorations`, `full=false` → `merge_decorations` (M11.4
clip/drop/split, structurally identical to `merge_style_spans`).
- `reshape()` rewritten as a sorted-boundary sweep over both spans
and decorations: every coverage edge becomes a chunk break.
Effective fg color = first matching decoration with a renderable
color, else span color, else default.
- `decoration_kind_to_color`: red error / yellow warning / blue info
/ dim hint; selection/search/current-line return `None`.
Session-5 findings (rule iii, both deferred)
- **M11.4 merge logic duplicated** between `StyleSpan` and
`Decoration`. Structural-but-minor; defer until a third instance
surfaces (peer-cursor decorations from `PresenceUpdate` are the
likely third point) so the generic shape is inducted from three
examples, not two.
- **Background-kind decorations need a wgpu quad pipeline**. glyphon
0.11 / cosmic-text 0.18 `Attrs` is foreground-only. Structural —
new render pass + composition story with text. Its own session,
not absorbed into Phase A.
Adversarial-verification framing
Probe #5 (active diagnostics + multi-frontend `PresenceUpdate`
overlap) — the diagnostics half is exercised; PresenceUpdate is its
own family and isn't consumed yet. Probe #3 (viewport-boundary
edges) gets re-tested: `merge_decorations` is the same code shape as
`merge_style_spans`, so an edge-case finding there would replicate.
Gates
`cargo fmt`; `cargo clippy --all-targets --workspace -D warnings`
clean; lib 1303 + protocol 11 = 1314; m4 83; m11_5 (--features crdt)
2.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Levi Neuwirth
2076a3682d