presence: fix stale peer selections after delete, select-all lag, ghost-peer removal (findings group Y)

- wasm core: CORE::onDocChanged() from both collab listeners (local commit AND
  remote apply) repaints peers' shapes from the live document + re-checks the
  local selection post-settle; PresenceStart registers the bridge listener
- wasm core: cursors on their own overlay trio; shapes repaint only when the
  non-cursor snapshot changes; new kicadCollabSetRemoteCursors (cursor-only
  update, PEER.id) in both TUs + merged editor + JSPI mutator allowlist
- presence.ts: size-aware trailing throttle for cursor/viewport publishes
  (128 KB/s budget) + parsed-peers memo; presence-kicad.ts: cursor-only push
  when the shape signature is unchanged
- gateway.ts: honor the `gone` control (removeAwarenessStates)
- specs: kicad stale-after-delete gate, web ghost-peer timing (+diag), unit
  select-all budget (pcbjam-shared → 4573a7c)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AScTR39aqyrY5i3ZFHmnMn

web/standalone/src/wasm/collab/gateway.ts

@@ -441,6 +441,19 @@ export class GatewayDocFacade implements YjsProvider {
       for (const cb of this.filesCbs) cb(msg.seq, msg.changes);
       return;
     }
+    if (msg.t === "gone") {
+      // A peer connection died; the gateway names its awareness clients. The
+      // clock-ordered binary tombstone may have been rejected (stale clock
+      // after a hibernation wake) — this removal is authoritative. A live
+      // client with one of these ids simply re-appears on its next update.
+      const remote = msg.clients.filter(
+        (id) => id !== this.doc.clientID && this.awareness.getStates().has(id),
+      );
+      if (remote.length > 0) {
+        removeAwarenessStates(this.awareness, remote, "gateway-gone");
+      }
+      return;
+    }
     // touched
     for (const cb of this.touchedCbs) cb();
   }

web/standalone/src/wasm/collab/presence-kicad.ts

@@ -36,6 +36,10 @@ export interface PresenceKicadModule {
   /** 0008: fit a leader's world rect (center + half-extents, IU) into this
    *  canvas — contain semantics. Absent on older wasm builds. */
   kicadCollabFitViewport?(cx: number, cy: number, halfW: number, halfH: number): void;
+  /** Findings Y-4: cursor-only update `{cursors:[{id, cursor}]}` for peers
+   *  already known from the last full snapshot — the wasm side repaints only
+   *  the cursor overlays, not every selection outline. Absent on older wasm. */
+  kicadCollabSetRemoteCursors?(json: string): void;
 }
 
 export interface PresenceKicadWindow {
@@ -212,6 +216,11 @@ export function bindKicadPresence(opts: {
   }
 
   // awareness → C++ ------------------------------------------------------------
+  // The last full snapshot's "shape" signature (everything except cursors):
+  // while it is unchanged, awareness changes are cursor ticks and go through
+  // the cheap cursor-only entry point (findings Y-4 — a select-all peer's
+  // 20 Hz cursor must not re-resolve + redraw 3000 outlines per tick).
+  let lastShapeSig = "";
   const pushRemote = () => {
     const peers = presence.peers();
     const snapshot: {
@@ -264,6 +273,17 @@ export function bindKicadPresence(opts: {
         xsel,
       });
     }
+    const shapeSig = JSON.stringify({
+      peers: snapshot.peers.map((p) => [p.id, p.name, p.color, p.selection, p.xsel ?? null]),
+      locks: snapshot.locks,
+    });
+    if (shapeSig === lastShapeSig && mod.kicadCollabSetRemoteCursors) {
+      mod.kicadCollabSetRemoteCursors(
+        JSON.stringify({ cursors: snapshot.peers.map((p) => ({ id: p.id, cursor: p.cursor })) }),
+      );
+      return;
+    }
+    lastShapeSig = shapeSig;
     mod.kicadCollabSetRemote(JSON.stringify(snapshot));
   };
 

web/standalone/src/wasm/collab/presence-select-all-lag.test.ts

@@ -0,0 +1,145 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+import * as Y from "yjs";
+import { Awareness, encodeAwarenessUpdate } from "y-protocols/awareness";
+import { createPresence, resetPresenceColorClaims, type PresencePeer } from "./presence";
+import { bindKicadPresence, type PresenceKicadWindow } from "./presence-kicad";
+
+/**
+ * REPRO (findings: "if user A selects everything, user B gets slow/laggy").
+ *
+ * Two amplifications stack on a big selection:
+ *  1. WIRE — awareness is a single JSON blob per client. Every cursor tick
+ *     (≤20/s) re-encodes the WHOLE state, selection included, so N selected
+ *     items cost ~N×40 bytes per tick on the wire, per peer.
+ *  2. BRIDGE — every awareness change (any peer's cursor move) rebuilds the
+ *     full `kicadCollabSetRemote` snapshot (all peers' full selections) and
+ *     the wasm side clears + redraws EVERY selection outline (pcbnew even
+ *     recomputes hulls / polygons per item). The 30ms trailing throttle only
+ *     coalesces bursts; a steady 20Hz cursor stream still means ~20 full
+ *     redraws of N outlines per second on B.
+ */
+
+const uuids = (n: number): string[] =>
+  Array.from({ length: n }, (_, i) => `${i.toString(16).padStart(8, "0")}-0000-0000-0000-000000000000`);
+
+afterEach(() => {
+  vi.useRealTimers();
+  resetPresenceColorClaims();
+});
+
+describe("select-all amplification", () => {
+  it("WIRE: one second of cursor motion after select-all stays inside the publish budget", () => {
+    vi.useFakeTimers();
+    const doc = new Y.Doc();
+    const awareness = new Awareness(doc);
+    const presence = createPresence({
+      awareness,
+      user: { id: "alice", name: "alice", color: "#000" },
+      tool: "eeschema",
+    });
+    let bytes = 0;
+    let updates = 0;
+    awareness.on("update", ({ updated }: { updated: number[] }) => {
+      if (!updated.includes(awareness.clientID)) return;
+      updates++;
+      bytes += encodeAwarenessUpdate(awareness, [awareness.clientID]).byteLength;
+    });
+
+    const drive = () => {
+      bytes = 0;
+      updates = 0;
+      for (let i = 0; i < 20; i++) {
+        presence.setCursor({ x: i, y: i });
+        vi.advanceTimersByTime(50);
+      }
+      vi.advanceTimersByTime(2500);
+      return { bytes, updates };
+    };
+
+    presence.setSelection([]);
+    const small = drive();
+    // No selection: every tick publishes as before (unthrottled).
+    expect(small.updates).toBe(20);
+
+    presence.setSelection(uuids(3000)); // select-all on a mid-size board
+    const big = drive();
+    // eslint-disable-next-line no-console
+    console.log(`awareness cursor motion/s: empty sel ${small.updates}×=${small.bytes}B, 3000-item sel ${big.updates}×=${big.bytes}B`);
+    // Was 20 × 117 KB ≈ 2.3 MB/s. The size-aware trailing throttle keeps a
+    // select-all peer's cursor traffic near the 128 KB/s budget while the
+    // last cursor position still lands (trailing edge).
+    expect(big.bytes).toBeLessThan(400 * 1024);
+    expect(big.updates).toBeGreaterThanOrEqual(1);
+    expect(big.updates).toBeLessThan(6);
+    expect((awareness.getLocalState() as { cursor: { x: number } }).cursor.x).toBe(19);
+    presence.destroy();
+    awareness.destroy();
+  });
+
+  it("BRIDGE: every peer cursor move re-pushes all N selection uuids to wasm", () => {
+    vi.useFakeTimers();
+    const setRemote = vi.fn<(json: string) => void>();
+    const setCursors = vi.fn<(json: string) => void>();
+    const mod = {
+      kicadCollabPresenceStart: vi.fn(),
+      kicadCollabSetRemote: setRemote,
+      kicadCollabSetRemoteCursors: setCursors,
+      kicadCollabGetViewport: vi.fn(() => '{"cx":0,"cy":0,"scale":1,"w":800,"h":600}'),
+      kicadCollabGetSelection: vi.fn(() => "[]"),
+    };
+    const subscribers = new Set<(p: PresencePeer[]) => void>();
+    let peers: PresencePeer[] = [];
+    const presence = {
+      peers: () => peers,
+      clients: () => peers,
+      self: () => ({ userId: "bob", clientId: 100 }),
+      subscribe(cb: (p: PresencePeer[]) => void) {
+        subscribers.add(cb);
+        return () => subscribers.delete(cb);
+      },
+      setCursor: vi.fn(),
+      setSelection: vi.fn(),
+      setViewport: vi.fn(),
+      colorOf: () => "#000",
+      destroy: vi.fn(),
+    };
+    const win: PresenceKicadWindow = {};
+    bindKicadPresence({ mod, win, presence });
+    setRemote.mockClear();
+
+    const selection = uuids(3000);
+    const alice = (cursor: { x: number; y: number }): PresencePeer => ({
+      clientId: 1,
+      user: { id: "alice", name: "alice", color: "#000" },
+      tool: "eeschema",
+      cursor,
+      selection,
+      updatedAt: Date.now(),
+    });
+
+    // alice moves her mouse for one second at the 20Hz emit cadence.
+    for (let i = 0; i < 20; i++) {
+      peers = [alice({ x: i, y: i })];
+      for (const cb of subscribers) cb(peers);
+      vi.advanceTimersByTime(50);
+    }
+    vi.advanceTimersByTime(100);
+
+    const pushes = setRemote.mock.calls.length;
+    const bytes = setRemote.mock.calls.reduce((s, [json]) => s + json.length, 0);
+    const uuidsPushed = setRemote.mock.calls.reduce(
+      (s, [json]) => s + (JSON.parse(json) as { peers: { selection: string[] }[] }).peers[0]!.selection.length,
+      0,
+    );
+    // eslint-disable-next-line no-console
+    console.log(`bridge: ${pushes} full setRemote pushes (${bytes}B JSON, ${uuidsPushed} uuids), ${setCursors.mock.calls.length} cursor-only pushes per second of cursor motion`);
+
+    // Cursor-only changes must not re-ship (and the wasm side re-resolve +
+    // redraw) the unchanged 3000-item selection 20×/s: ONE full snapshot
+    // introduces the selection, the ticks ride the cursor-only entry point.
+    expect(uuidsPushed).toBeLessThan(selection.length * 2);
+    expect(setCursors.mock.calls.length).toBeGreaterThanOrEqual(15);
+    const last = JSON.parse(setCursors.mock.calls.at(-1)![0]) as { cursors: { id: string; cursor: { x: number } }[] };
+    expect(last.cursors[0]).toEqual({ id: "alice", cursor: { x: 19, y: 19 } });
+  });
+});

web/standalone/src/wasm/collab/presence.ts

@@ -70,6 +70,16 @@ export interface PresenceHandle {
 // so one user keeps one color everywhere in a session; a second tab of the
 // same user ADOPTS the existing color instead of claiming a new one.
 
+/** Cursor/viewport publish budget: bytes of published selection per second
+ *  of high-frequency traffic. 128 KB/s ⇒ a 3000-item selection (~117 KB)
+ *  publishes cursors at ~1 Hz; anything under ~6 KB (150 items) is not
+ *  throttled at all (the wasm side already caps cursor emits at 20 Hz). */
+const HF_BUDGET_BYTES_PER_SEC = 128 * 1024;
+const HF_MAX_INTERVAL_MS = 2000;
+/** Below this the wasm emit cadence (50 ms) already bounds the rate — publish
+ *  synchronously, exactly as before. */
+const HF_MIN_INTERVAL_MS = 50;
+
 // Per-user claims in this JS context (one user per tab in production; the
 // map keeps multi-client unit tests deterministic).
 const g_claims = new Map<string, string>();
@@ -187,6 +197,36 @@ export function createPresence(opts: {
     awareness.setLocalState({ ...current, ...fields, updatedAt: Date.now() });
   };
 
+  // Select-all lag (findings Y-4): awareness ships the WHOLE state on every
+  // change, so with a large selection each 20 Hz cursor/viewport tick
+  // re-sends the selection (3000 items ≈ 117 KB per tick). Rate the
+  // high-frequency fields by payload size: the bigger the published
+  // selection, the longer the trailing interval between cursor/viewport
+  // publishes (a small selection is unthrottled; select-all ≈ 1 Hz).
+  let selectionBytes = 2;
+  let hfTimer: ReturnType<typeof setTimeout> | undefined;
+  let hfPending: Partial<PresenceState> = {};
+  let hfLastAt = 0;
+  const hfInterval = () => Math.min(HF_MAX_INTERVAL_MS, (selectionBytes / HF_BUDGET_BYTES_PER_SEC) * 1000);
+  const patchHighFrequency = (fields: Partial<PresenceState>) => {
+    hfPending = { ...hfPending, ...fields };
+    const wait = hfInterval();
+    if (wait < HF_MIN_INTERVAL_MS) {
+      hfPending = {};
+      patch(fields);
+      return;
+    }
+    if (hfTimer) return;
+    const due = Math.max(0, hfLastAt + wait - Date.now());
+    hfTimer = setTimeout(() => {
+      hfTimer = undefined;
+      hfLastAt = Date.now();
+      const p = hfPending;
+      hfPending = {};
+      patch(p);
+    }, due);
+  };
+
   patch({
     user,
     tool: opts.tool,
@@ -249,7 +289,12 @@ export function createPresence(opts: {
     }
   };
 
+  // Parsed-clients memo: peers()/clients() are both read on every awareness
+  // change by the bridge, and each zod parse of a big selection is costly.
+  // States only change through awareness events, so one parse per change.
+  let clientsMemo: PresencePeer[] | null = null;
   function clients(): PresencePeer[] {
+    if (clientsMemo) return clientsMemo;
     const out: PresencePeer[] = [];
     for (const [clientId, raw] of awareness.getStates()) {
       if (clientId === awareness.clientID) continue;
@@ -257,7 +302,8 @@ export function createPresence(opts: {
       if (!parsed.success) continue;
       out.push({ ...parsed.data, clientId });
     }
-    return out.sort((a, b) => a.clientId - b.clientId);
+    clientsMemo = out.sort((a, b) => a.clientId - b.clientId);
+    return clientsMemo;
   }
 
   function peers(): PresencePeer[] {
@@ -275,6 +321,7 @@ export function createPresence(opts: {
 
   const subscribers = new Set<(peers: PresencePeer[]) => void>();
   const onChange = () => {
+    clientsMemo = null;
     resolveCollision();
     if (!subscribers.size) return;
     const snapshot = peers();
@@ -302,13 +349,14 @@ export function createPresence(opts: {
       return () => subscribers.delete(cb);
     },
     setCursor(pos) {
-      patch({ cursor: pos });
+      patchHighFrequency({ cursor: pos });
     },
     setSelection(uuids) {
+      selectionBytes = JSON.stringify(uuids).length;
       patch({ selection: uuids });
     },
     setViewport(rect) {
-      patch({ viewport: rect });
+      patchHighFrequency({ viewport: rect });
     },
     colorOf(userId) {
       if (userId === user.id) return user.color;
@@ -331,6 +379,8 @@ export function createPresence(opts: {
       }
       awareness.off("change", onChange);
       subscribers.clear();
+      if (hfTimer) clearTimeout(hfTimer);
+      hfTimer = undefined;
       awareness.setLocalState(null);
     },
   };