perf(ios/chat): skip re-rendering unchanged bubbles while typing

apps/ios/CovenCave/CovenCave/Views/ChatView.swift

@@ -278,6 +278,7 @@ struct ChatView: View {
                                       onReply: { beginReply($0) },
                                       operatorName: app.operatorDisplayName,
                                       operatorAvatarURL: app.operatorAvatarURL)
+                        .equatable()
                         .id(message.id)
                         // New bubbles settle in with a soft rise-and-fade
                         // (native Messages behaviour) instead of popping;

apps/ios/CovenCave/CovenCave/Views/MessageBubble.swift

@@ -458,3 +458,29 @@ struct SuggestionPills: View {
         .padding(.top, 6)
     }
 }
+
+// Skip re-rendering a bubble when its render-affecting inputs are unchanged.
+// ChatView's composer keeps `draft` in the same view body as the message list,
+// so every keystroke invalidates ChatView.body and would otherwise re-diff
+// every bubble (each hosts a WKWebView) — the cause of slow typing on long
+// threads. Closures are excluded (they capture fresh state each render but
+// don't change what's drawn); optional-action closures are compared by presence
+// since that toggles which buttons appear. Environment values and the complete
+// familiar model are included because they directly control colours, markdown
+// styling, and the familiar attribution row.
+extension MessageBubble: Equatable {
+    static func == (lhs: MessageBubble, rhs: MessageBubble) -> Bool {
+        lhs.message == rhs.message
+            && lhs.isGroup == rhs.isGroup
+            && lhs.familiar == rhs.familiar
+            && lhs.isLast == rhs.isLast
+            && lhs.operatorName == rhs.operatorName
+            && lhs.operatorAvatarURL == rhs.operatorAvatarURL
+            && lhs.colorScheme == rhs.colorScheme
+            && lhs.chrome == rhs.chrome
+            && (lhs.onRetry == nil) == (rhs.onRetry == nil)
+            && (lhs.onReply == nil) == (rhs.onReply == nil)
+            && (lhs.onOpenReader == nil) == (rhs.onOpenReader == nil)
+            && (lhs.onForward == nil) == (rhs.onForward == nil)
+    }
+}

scripts/ios-message-bubble-equatable.test.mjs

@@ -0,0 +1,59 @@
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+
+const root = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "..");
+const chatView = fs.readFileSync(
+  path.join(root, "apps/ios/CovenCave/CovenCave/Views/ChatView.swift"),
+  "utf8",
+);
+const messageBubble = fs.readFileSync(
+  path.join(root, "apps/ios/CovenCave/CovenCave/Views/MessageBubble.swift"),
+  "utf8",
+);
+const runner = fs.readFileSync(path.join(root, "scripts/run-tests.mjs"), "utf8");
+
+assert.match(
+  chatView,
+  /MessageBubble\([\s\S]*?\)\s*\.equatable\(\)\s*\.id\(message\.id\)/,
+  "ChatView should skip re-rendering bubbles whose render inputs are unchanged",
+);
+
+assert.match(
+  messageBubble,
+  /extension MessageBubble: Equatable/,
+  "MessageBubble should define its render-input equality contract",
+);
+
+assert.match(
+  messageBubble,
+  /lhs\.familiar == rhs\.familiar/,
+  "familiar presentation changes should invalidate an equatable bubble",
+);
+
+assert.match(
+  messageBubble,
+  /lhs\.colorScheme == rhs\.colorScheme/,
+  "light and dark appearance changes should invalidate an equatable bubble",
+);
+
+assert.match(
+  messageBubble,
+  /lhs\.chrome == rhs\.chrome/,
+  "theme palette changes should invalidate an equatable bubble",
+);
+
+assert.doesNotMatch(
+  messageBubble,
+  /lhs\.familiar\?\.id == rhs\.familiar\?\.id/,
+  "familiar equality must not ignore refreshed names, avatars, or colours",
+);
+
+assert.match(
+  runner,
+  /"scripts\/ios-message-bubble-equatable\.test\.mjs"/,
+  "mobile test suite should run the message-bubble equality regression",
+);
+
+console.log("ios-message-bubble-equatable.test.mjs: ok");

scripts/run-tests.mjs

@@ -1082,6 +1082,7 @@ export const SUITES = {
     "scripts/ios-markdown-accent.test.mjs",
     "scripts/ios-message-forwarding.test.mjs",
     "scripts/ios-message-retry.test.mjs",
+    "scripts/ios-message-bubble-equatable.test.mjs",
     "scripts/ios-chat-draft-lag.test.mjs",
     "scripts/ios-chat-thread-no-search.test.mjs",
     "scripts/ios-development-code-title.test.mjs",