perf(client): repeated server settings keep the same settings object

packages/client-runtime/src/state/serverConfigProjection.test.ts

@@ -1,9 +1,18 @@
-import type { ServerConfig, ServerConfigStreamEvent } from "@t3tools/contracts";
+import {
+  DEFAULT_SERVER_SETTINGS,
+  ServerSettings,
+  type ServerConfig,
+  type ServerConfigStreamEvent,
+} from "@t3tools/contracts";
 import * as Option from "effect/Option";
+import * as Schema from "effect/Schema";
 import { describe, expect, it } from "vite-plus/test";
 
 import { applyServerConfigProjection, reuseUnchanged } from "./serverConfigProjection.ts";
 
+const encodeSettings = Schema.encodeSync(ServerSettings);
+const decodeSettings = Schema.decodeSync(ServerSettings);
+
 describe("reuseUnchanged", () => {
   const provider = (checkedAt: string, skills: ReadonlyArray<string>) => ({
     instanceId: "claude",
@@ -53,4 +62,20 @@ describe("applyServerConfigProjection settingsUpdated", () => {
     expect(nextSettings.providerInstances.codex).toBe(settings.providerInstances.codex);
     expect(nextSettings.providerInstances.claude.config.launchArgs).toBe("--verbose");
   });
+
+  it("keeps the settings object when an update repeats the current settings", () => {
+    const wire = encodeSettings(DEFAULT_SERVER_SETTINGS);
+    const decode = () => decodeSettings(structuredClone(wire));
+    const settings = decode();
+    const current = Option.some({
+      config: { settings } as unknown as ServerConfig,
+      latestEvent: {} as ServerConfigStreamEvent,
+      source: "live" as const,
+    });
+    const next = applyServerConfigProjection(current, {
+      type: "settingsUpdated",
+      payload: { settings: decode() },
+    } as ServerConfigStreamEvent);
+    expect(Option.getOrThrow(next).config).toBe(Option.getOrThrow(current).config);
+  });
 });

packages/client-runtime/src/state/serverConfigProjection.ts

@@ -1,4 +1,5 @@
 import type { ServerConfig, ServerConfigStreamEvent } from "@t3tools/contracts";
+import * as Equal from "effect/Equal";
 import * as Option from "effect/Option";
 
 export interface ServerConfigProjection {
@@ -44,6 +45,8 @@ export function reuseUnchanged<T>(previous: unknown, next: T): T {
     });
     return (same ? previous : merged) as T;
   }
+  // Decoded settings carry Durations, which are fresh instances on every push.
+  if (Equal.isEqual(next)) return (Equal.equals(previous, next) ? previous : next) as T;
   if (Object.getPrototypeOf(next) !== Object.prototype) return next;
   const before = previous as Record<string, unknown>;
   const after = next as Record<string, unknown>;
@@ -104,14 +107,17 @@ export function applyServerConfigProjection(
         source: "live",
       }));
     case "settingsUpdated":
-      return Option.map(current, (projection) => ({
-        config: {
-          ...projection.config,
-          settings: reuseUnchanged(projection.config.settings, event.payload.settings),
-        },
-        latestEvent: event,
-        source: "live",
-      }));
+      return Option.map(current, (projection) => {
+        const settings = reuseUnchanged(projection.config.settings, event.payload.settings);
+        return {
+          config:
+            settings === projection.config.settings
+              ? projection.config
+              : { ...projection.config, settings },
+          latestEvent: event,
+          source: "live",
+        };
+      });
     case "environmentThemesUpdated":
       return Option.map(current, (projection) => ({
         config: {