fix(auth): prevent infinite loading hang on Firestore snapshot error

src/context/AuthContext.tsx

@@ -338,6 +338,10 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {
                 setUser(updatedUser as User);
               }
               setIsLoading(false);
+            },
+            (error) => {
+              console.error('Firestore user sync error:', error);
+              setIsLoading(false);
             }
           );
 

src/context/__tests__/AuthContext.test.tsx

@@ -1,10 +1,20 @@
 import '@testing-library/jest-dom';
 import React from 'react';
-import { render, screen, act } from '@testing-library/react';
+import { render, screen, act, waitFor } from '@testing-library/react';
 import { AuthProvider, useAuth } from '../AuthContext';
 
 const mockSignIn = jest.fn();
 const mockSignOut = jest.fn();
+const mockOnAuthStateChanged = jest.fn(() => jest.fn());
+const mockOnSnapshot = jest.fn(
+  (
+    _ref: unknown,
+    cb: (snapshot: { exists: () => boolean; data?: () => Record<string, unknown> }) => void
+  ) => {
+    cb({ exists: () => false });
+    return jest.fn();
+  }
+);
 
 const firebaseMock = {
   auth: {},
@@ -15,7 +25,7 @@ const firebaseMock = {
 
 jest.mock('firebase/auth', () => ({
   getAuth: () => ({}),
-  onAuthStateChanged: jest.fn(() => jest.fn()),
+  onAuthStateChanged: (...args: unknown[]) => mockOnAuthStateChanged(...args),
   signInWithEmailAndPassword: (...args: unknown[]) => mockSignIn(...args),
   signOut: (...args: unknown[]) => mockSignOut(...args),
   setPersistence: jest.fn(() => Promise.resolve()),
@@ -41,12 +51,11 @@ jest.mock('firebase/firestore', () => ({
   doc: jest.fn(() => ({})),
   getDoc: jest.fn(() => Promise.resolve({ exists: () => false })),
   setDoc: jest.fn(() => Promise.resolve()),
-  onSnapshot: jest.fn(
-    (_ref: unknown, cb: (snapshot: { exists: () => boolean }) => void) => {
-      cb({ exists: () => false });
-      return jest.fn();
-    }
-  ),
+  onSnapshot: (
+    ref: unknown,
+    cb: (snapshot: { exists: () => boolean; data?: () => Record<string, unknown> }) => void,
+    errorCb?: (error: Error) => void
+  ) => mockOnSnapshot(ref, cb, errorCb),
   writeBatch: jest.fn(() => ({
     commit: jest.fn(),
     set: jest.fn(),
@@ -76,7 +85,7 @@ jest.mock('@/lib/points', () => ({
 }));
 
 function TestHarness() {
-  const { user, login, logout } = useAuth();
+  const { user, isLoading, login, logout } = useAuth();
   const [error, setError] = React.useState<string | null>(null);
   const handleLogin = async () => {
     try {
@@ -89,6 +98,7 @@ function TestHarness() {
     <div>
       <span data-testid="user-email">{user?.email || 'null'}</span>
       <span data-testid="error">{error || ''}</span>
+      <span data-testid="loading-status">{isLoading ? 'loading' : 'done'}</span>
       <button data-testid="login-btn" onClick={handleLogin}>
         login
       </button>
@@ -110,6 +120,16 @@ function renderWithAuth() {
 beforeEach(() => {
   jest.clearAllMocks();
   localStorage.clear();
+  mockOnAuthStateChanged.mockImplementation(() => jest.fn());
+  mockOnSnapshot.mockImplementation(
+    (
+      _ref: unknown,
+      cb: (snapshot: { exists: () => boolean; data?: () => Record<string, unknown> }) => void
+    ) => {
+      cb({ exists: () => false });
+      return jest.fn();
+    }
+  );
 });
 
 describe('AuthContext', () => {
@@ -207,4 +227,62 @@ describe('AuthContext', () => {
       firebaseMock.firebaseAvailable = true;
     });
   });
+
+  describe('Firestore onSnapshot loading state', () => {
+    it('sets isLoading to false when Firestore sync succeeds', async () => {
+      mockOnAuthStateChanged.mockImplementation((_auth: unknown, callback: (user: { uid: string; email: string | null; displayName: string | null } | null) => void) => {
+        callback({ uid: 'test-uid', email: 'test@example.com', displayName: 'Test User' });
+        return jest.fn();
+      });
+
+      mockOnSnapshot.mockImplementation(
+        (
+          _ref: unknown,
+          cb: (snapshot: { exists: () => boolean; data?: () => Record<string, unknown> }) => void
+        ) => {
+          cb({
+            exists: () => true,
+            data: () => ({
+              role: 'member',
+              points: 100,
+            }),
+          });
+          return jest.fn();
+        }
+      );
+
+      renderWithAuth();
+
+      await waitFor(() => {
+        expect(screen.getByTestId('loading-status')).toHaveTextContent('done');
+      });
+      expect(screen.getByTestId('user-email')).toHaveTextContent('test@example.com');
+    });
+
+    it('sets isLoading to false and does not hang when Firestore sync fails', async () => {
+      mockOnAuthStateChanged.mockImplementation((_auth: unknown, callback: (user: { uid: string; email: string | null; displayName: string | null } | null) => void) => {
+        callback({ uid: 'test-uid-error', email: 'test-error@example.com', displayName: 'Test User Error' });
+        return jest.fn();
+      });
+
+      mockOnSnapshot.mockImplementation(
+        (
+          _ref: unknown,
+          _cb: (snapshot: { exists: () => boolean; data?: () => Record<string, unknown> }) => void,
+          errorCb?: (error: Error) => void
+        ) => {
+          if (errorCb) {
+            errorCb(new Error('Mocked Firestore Permission Denied'));
+          }
+          return jest.fn();
+        }
+      );
+
+      renderWithAuth();
+
+      await waitFor(() => {
+        expect(screen.getByTestId('loading-status')).toHaveTextContent('done');
+      });
+    });
+  });
 });