fix(context): Fix snapshot recovery across sessions. (#26939)

packages/core/src/context/system-tests/hysteresis.test.ts

@@ -9,7 +9,7 @@ import { SimulationHarness } from './simulationHarness.js';
 import { createMockLlmClient } from '../testing/contextTestUtils.js';
 import type { ContextProfile } from '../config/profiles.js';
 import { generalistProfile } from '../config/profiles.js';
-import type { Content } from '@google/genai';
+import { type HistoryTurn } from '../../core/agentChatHistory.js';
 
 describe('Context Manager Hysteresis Tests', () => {
   const mockLlmClient = createMockLlmClient(['<SNAPSHOT>']);
@@ -18,6 +18,7 @@ describe('Context Manager Hysteresis Tests', () => {
     ...generalistProfile,
     name: 'Hysteresis Stress Test',
     config: {
+      ...generalistProfile.config,
       budget: {
         maxTokens: 5000,
         retainedTokens: 1000,
@@ -26,9 +27,13 @@ describe('Context Manager Hysteresis Tests', () => {
     },
   });
 
-  const getProjectionTokens = (proj: Content[], harness: SimulationHarness) =>
+  const getProjectionTokens = (
+    proj: HistoryTurn[],
+    harness: SimulationHarness,
+  ) =>
     proj.reduce(
-      (sum, c) => sum + harness.env.tokenCalculator.calculateContentTokens(c),
+      (sum, c) =>
+        sum + harness.env.tokenCalculator.calculateContentTokens(c.content),
       0,
     );
 
@@ -57,7 +62,7 @@ describe('Context Manager Hysteresis Tests', () => {
     // No snapshot because maxTokens (5000) not exceeded, and deficit < threshold.
     expect(
       state.finalProjection.some((c) =>
-        c.parts?.some((p) => p.text?.includes('<SNAPSHOT>')),
+        c.content.parts?.some((p) => p.text?.includes('<SNAPSHOT>')),
       ),
     ).toBe(false);
 
@@ -79,7 +84,7 @@ describe('Context Manager Hysteresis Tests', () => {
     state = await harness.getGoldenState();
     expect(
       state.finalProjection.some((c) =>
-        c.parts?.some((p) => p.text?.includes('<SNAPSHOT>')),
+        c.content.parts?.some((p) => p.text?.includes('<SNAPSHOT>')),
       ),
     ).toBe(true);
   });
@@ -108,7 +113,7 @@ describe('Context Manager Hysteresis Tests', () => {
     let state = await harness.getGoldenState();
     expect(
       state.finalProjection.some((c) =>
-        c.parts?.some((p) => p.text?.includes('<SNAPSHOT>')),
+        c.content.parts?.some((p) => p.text?.includes('<SNAPSHOT>')),
       ),
     ).toBe(true);
 

packages/core/src/context/system-tests/lifecycle.golden.test.ts

@@ -17,6 +17,7 @@ expect.addSnapshotSerializer({
     (/[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}/i.test(
       val,
     ) ||
+      /^[0-9a-f]{32}$/i.test(val) ||
       /[\\/]tmp[\\/]sim/.test(val)),
   print: (val) => {
     if (typeof val !== 'string') return `"${val}"`;
@@ -25,6 +26,7 @@ expect.addSnapshotSerializer({
         /[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}/gi,
         '<UUID>',
       )
+      .replace(/\b[0-9a-f]{32}\b/gi, '<UUID>')
       .replace(/[\\/]tmp[\\/]sim[^\s"'\]]*/g, '<MOCKED_DIR>');
 
     // Also scrub timestamps in filenames like blob_1234567890_...

packages/core/src/context/system-tests/simulationHarness.ts

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+import { randomUUID } from 'node:crypto';
 import { ContextManager } from '../contextManager.js';
 import { AgentChatHistory } from '../../core/agentChatHistory.js';
 import type { Content } from '@google/genai';
@@ -98,7 +99,8 @@ export class SimulationHarness {
   async simulateTurn(messages: Content[]) {
     // 1. Append the new messages
     const currentHistory = this.chatHistory.get();
-    this.chatHistory.set([...currentHistory, ...messages]);
+    const turns = messages.map((m) => ({ id: randomUUID(), content: m }));
+    this.chatHistory.set([...currentHistory, ...turns]);
 
     // 2. Measure tokens immediately after append
     const tokensBefore = this.env.tokenCalculator.calculateConcreteListTokens(