fix(core): reset session-scoped state on resumption (#26342)

packages/core/src/config/config.test.ts

@@ -23,6 +23,7 @@ import { createMockSandboxConfig } from '@google/gemini-cli-test-utils';
 import { DEFAULT_MAX_ATTEMPTS } from '../utils/retry.js';
 import { ExperimentFlags } from '../code_assist/experiments/flagNames.js';
 import { debugLogger } from '../utils/debugLogger.js';
+import { coreEvents } from '../utils/events.js';
 import { ApprovalMode } from '../policy/types.js';
 import {
   HookType,
@@ -1940,6 +1941,70 @@ describe('Server Config (config.ts)', () => {
     expect(config.getSessionId()).toBe('session-two');
     expect(config.getApprovedPlanPath()).toBeUndefined();
   });
+
+  it('performs a comprehensive reset of all session-scoped state when sessionId changes', async () => {
+    const config = new Config({
+      ...baseParams,
+      sessionId: 'session-one',
+      plan: true,
+      tracker: true,
+    });
+
+    await config.initialize();
+
+    // 1. "Dirty" the session state
+    const oldTrackerService = config.getTrackerService();
+    config.setApprovedPlanPath('/tmp/plan.md');
+    config.topicState.setTopic('Old Topic', 'Old Intent');
+    config.getSkillManager().activateSkill('old-skill');
+    config.getModelAvailabilityService().markTerminal('model-1', 'quota');
+    config.setLatestApiRequest({} as never);
+
+    // Interface to access private fields without 'any'
+    interface PrivateConfig {
+      modelQuotas: Map<string, unknown>;
+      lastEmittedQuotaRemaining: number | undefined;
+      lastEmittedQuotaLimit: number | undefined;
+      lastQuotaFetchTime: number;
+      hasAccessToPreviewModel: boolean | null;
+    }
+    const configInternal = config as unknown as PrivateConfig;
+
+    // Mock internal quota state
+    configInternal.modelQuotas.set('model-1', { remaining: 0, limit: 100 });
+    configInternal.lastEmittedQuotaRemaining = 0;
+    configInternal.lastEmittedQuotaLimit = 100;
+    configInternal.lastQuotaFetchTime = 12345;
+    configInternal.hasAccessToPreviewModel = true;
+
+    // Listen for quota event
+    const emitQuotaSpy = vi.spyOn(coreEvents, 'emitQuotaChanged');
+
+    // 2. Trigger session change
+    config.setSessionId('session-two');
+
+    // 3. Verify EVERYTHING is reset
+    expect(config.getSessionId()).toBe('session-two');
+    expect(config.getApprovedPlanPath()).toBeUndefined();
+    expect(config.topicState.getTopic()).toBeUndefined();
+    expect(config.topicState.getIntent()).toBeUndefined();
+    expect(config.getSkillManager().isSkillActive('old-skill')).toBe(false);
+    expect(config.getTrackerService()).not.toBe(oldTrackerService);
+    expect(
+      config.getModelAvailabilityService().snapshot('model-1').available,
+    ).toBe(true);
+    expect(config.getLatestApiRequest()).toBeUndefined();
+
+    // Quota resets
+    expect(configInternal.modelQuotas.size).toBe(0);
+    expect(configInternal.lastEmittedQuotaRemaining).toBeUndefined();
+    expect(configInternal.lastEmittedQuotaLimit).toBeUndefined();
+    expect(configInternal.lastQuotaFetchTime).toBe(0);
+    expect(configInternal.hasAccessToPreviewModel).toBeNull();
+
+    // Event emission
+    expect(emitQuotaSpy).toHaveBeenCalledWith(undefined, undefined, undefined);
+  });
 });
 
 describe('GemmaModelRouterSettings', () => {

packages/core/src/config/config.ts

@@ -1803,6 +1803,24 @@ export class Config implements McpContext, AgentLoopContext {
     this._sessionId = sessionId;
     this.storage.setSessionId(sessionId);
     this.trackerService = undefined;
+    this.approvedPlanPath = undefined;
+    this.topicState.reset();
+    this.skillManager.reset();
+    this.latestApiRequest = undefined;
+    this.lastModeSwitchTime = performance.now();
+    this.compressionTruncationCounter = 0;
+    this.quotaErrorOccurred = false;
+    this.creditsNotificationShown = false;
+    this.modelAvailabilityService.reset();
+    this.modelQuotas.clear();
+    this.lastRetrievedQuota = undefined;
+    this.lastQuotaFetchTime = 0;
+    this.hasAccessToPreviewModel = null;
+
+    // Force an event emission to clear the UI display
+    coreEvents.emitQuotaChanged(undefined, undefined, undefined);
+    this.lastEmittedQuotaRemaining = undefined;
+    this.lastEmittedQuotaLimit = undefined;
 
     if (previousPlansDir) {
       this.refreshSessionScopedPlansDirectory(previousPlansDir);
@@ -1811,7 +1829,6 @@ export class Config implements McpContext, AgentLoopContext {
 
   resetNewSessionState(sessionId: string): void {
     this.setSessionId(sessionId);
-    this.approvedPlanPath = undefined;
   }
 
   setTerminalBackground(terminalBackground: string | undefined): void {

packages/core/src/skills/skillManager.test.ts

@@ -318,6 +318,20 @@ description: project-desc
     expect(service.isAdminEnabled()).toBe(false);
   });
 
+  it('should reset active skill names', () => {
+    const service = new SkillManager();
+    service.activateSkill('skill-1');
+    service.activateSkill('skill-2');
+
+    expect(service.isSkillActive('skill-1')).toBe(true);
+    expect(service.isSkillActive('skill-2')).toBe(true);
+
+    service.reset();
+
+    expect(service.isSkillActive('skill-1')).toBe(false);
+    expect(service.isSkillActive('skill-2')).toBe(false);
+  });
+
   describe('Conflict Detection', () => {
     it('should emit UI warning when a non-built-in skill is overridden', async () => {
       const emitFeedbackSpy = vi.spyOn(coreEvents, 'emitFeedback');

packages/core/src/skills/skillManager.ts

@@ -26,6 +26,13 @@ export class SkillManager {
     this.skills = [];
   }
 
+  /**
+   * Resets session-scoped state (active skill names).
+   */
+  reset(): void {
+    this.activeSkillNames.clear();
+  }
+
   /**
    * Sets administrative settings for skills.
    */