Description

0ee7360 introduced a change such that when the app is cold-started and Engine is initialized, RemoteFeatureFlagController is no longer instructed to reuse feature flags from a previous start, but rather, it will fetch them all over again. This change was made so that by simply listening to RemoteFeatureFlagController:stateChange, the RPC failover mode in NetworkController could be easily enabled or disabled.

In hindsight, this changed increased the start time of the app, negatively impacting performance. This is particularly noticeable on low-end devices where the app is frequently killed and restarted automatically due to out-of-memory issues. Also, changing the behavior of RemoteFeatureFlagController:stateChange in the way described above is admittedly strange.

To address this, this PR once again initializes RemoteFeatureFlagController from persisted state. As for NetworkController, it now correctly asks for the RemoteFeatureFlagController state once it is initialized and uses it to switch the RPC failover mode.

Changelog

CHANGELOG entry: Don't re-fetch feature flags on app restart, but rely on persistence instead

Related issues

(N/A)

Manual testing steps

1. Check out this branch.
2. Add QUICKNODE_ environment variables to .js.env. Ask me for what they should be.
3. Check out this branch, run yarn setup:expo, run yarn watch:clean.
4. Open node_modules/@metamask/network-controller/dist/rpc-service/rpc-service.cjs, look for async function _RpcService_processRequest and make these changes:

   async function _RpcService_processRequest(fetchOptions) {
       let response;
       try {
           return await __classPrivateFieldGet(this, _RpcService_policy, "f").execute(async () => {
   +           console.log('[REQUEST]', this.endpointUrl.toString(), 'with', fetchOptions);
   +           if (
   +             this.endpointUrl.toString().includes("linea-mainnet.infura.io") ||
   +             this.endpointUrl.toString().includes("mainnet.era.zksync.io")
   +           ) {
   +               console.log('[RESPONSE]', this.endpointUrl.toString(), '=> 502');
   +               throw new controller_utils_1.HttpError(502);
   +           }
               response = await __classPrivateFieldGet(this, _RpcService_fetch, "f").call(this, this.endpointUrl, fetchOptions);
   +           console.log('[RESPONSE]', this.endpointUrl.toString(), '=>', response.status);
               if (!response.ok) {
                   throw new controller_utils_1.HttpError(response.status);
               }
               return await response.json();
           });
       }

5. Open app/core/Engine/controllers/network-controller-init.ts, look for new NetworkController, and make these changes:

           return {
             ...commonOptions,
             policyOptions: {
               maxRetries,
   -           maxConsecutiveFailures: (maxRetries + 1) * 7,
   +           maxConsecutiveFailures: (maxRetries + 1) * 4,
             },
           };
         },
         additionalDefaultNetworks,
       };
       const networkController = new NetworkController(networkControllerOptions);

6. Open the app, go through onboarding if needed.
7. Once on the home screen, switch to Linea.
8. Monitor the messages appearing in your terminal. Pretty quickly, you should see a line that says [REQUEST] https://linea-mainnet.infura.io/v3/<api key>... with a line under this is [RESPONSE] https://linea-mainnet.infura.io/v3/<api key> => 502.
9. Pull down on the token list a few times to refresh it.
10. Eventually you should start to see lines in the terminal such as [REQUEST] https://<name>.linea-mainnet.quiknode.pro/<api-key>. This is an indicator that the RPC failover logic is still working.

Screenshots/Recordings

(N/A)

Before

After

Pre-merge author checklist

• I’ve followed MetaMask Contributor Docs and MetaMask Mobile Coding Standards.
• I've completed the PR template to the best of my ability
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
• I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.