fix(settings): Handle null Apollo cache reads safely

Because:

* Sentry reports type errors when GQL cache reads return null

This commit:

* Updates Apollo readQuery usage to handle null results safely
* Tightens Typescript typing for cache reads to avoid destructuring null
* Switches from `cache.readQuery` to `client.readQuery` for safer, supported cache access
* Removes unused getProfileInfo getter

Closes #FXA-12756

Author: vpomerleau

packages/fxa-settings/src/models/Account.ts

@@ -388,13 +388,17 @@ export class Account implements AccountData {
     }
   }
 
-  private get data() {
-    const { account } = this.apolloClient.cache.readQuery<{
-      account: AccountData;
-    }>({
+  private get data(): AccountData {
+    // readQuery is cache-only by default
+    const result = this.apolloClient.readQuery<{ account: AccountData }>({
       query: GET_ACCOUNT,
-    })!;
-    return account;
+    });
+
+    if (!result?.account) {
+      throw new Error('Account data not loaded from Apollo cache');
+    }
+
+    return result.account;
   }
 
   get loading() {
@@ -541,32 +545,12 @@ export class Account implements AccountData {
     );
   }
 
-  async getSecurityEvents() {
+  async getSecurityEvents(): Promise<SecurityEvent[]> {
     const { data } = await this.apolloClient.query({
       fetchPolicy: 'network-only',
       query: GET_SECURITY_EVENTS,
     });
-    const { account } = data;
-    return account.securityEvents;
-  }
-
-  async getProfileInfo() {
-    try {
-      const { data } = await this.apolloClient.query({
-        fetchPolicy: 'network-only',
-        query: GET_PROFILE_INFO,
-      });
-      const { account } = data;
-      return account as ProfileInfo;
-    } catch (err) {
-      const errno = (err as ApolloError).graphQLErrors[0].extensions?.errno as
-        | number
-        | undefined;
-      if (errno && AuthUiErrorNos[errno]) {
-        throw AuthUiErrorNos[errno];
-      }
-      throw AuthUiErrors.UNEXPECTED_ERROR;
-    }
+    return data?.account?.securityEvents ?? [];
   }
 
   async getRecoveryKeyBundle(

packages/fxa-settings/src/models/contexts/SettingsContext.ts

@@ -7,7 +7,7 @@ import React from 'react';
 import config from '../../lib/config';
 import firefox, { FirefoxCommand } from '../../lib/channels/firefox';
 import { createApolloClient } from '../../lib/gql';
-import { Account, GET_PROFILE_INFO } from '../Account';
+import { GET_PROFILE_INFO } from '../Account';
 import { AlertBarInfo } from '../AlertBarInfo';
 
 export const INITIAL_SETTINGS_QUERY = gql`
@@ -95,17 +95,25 @@ export function initializeSettingsContext() {
   const alertBarInfo = new AlertBarInfo();
   const apolloClient = createApolloClient(config.servers.gql.url);
 
+  const GET_UID_QUERY = gql`
+    query GetUid {
+      account {
+        uid
+      }
+    }
+  `;
+
   const isForCurrentUser = (event: Event) => {
-    const { account } = apolloClient.cache.readQuery<{ account: Account }>({
-      query: gql`
-        query GetUid {
-          account {
-            uid
-          }
-        }
-      `,
-    })!;
-    return account.uid === (event as CustomEvent).detail.uid;
+    const data = apolloClient.readQuery<{ account: { uid: string } }>({
+      query: GET_UID_QUERY,
+    });
+
+    if (!data?.account?.uid) {
+      return false;
+    }
+    const currentUid = data.account.uid;
+    const eventUid = (event as CustomEvent).detail?.uid;
+    return currentUid != null && currentUid === eventUid;
   };
 
   firefox.addEventListener(FirefoxCommand.ProfileChanged, (event) => {