fix: Network controller race condition after state update (#5122)

## Explanation

Fixes a race condition where:

- You update a network with a new endpoint.
- In the `stateChange` subscription callback, call
`getNetworkConfigurationByNetworkClientId` on the new endpoint.
- It returns undefined.

This occurs because the `network client id -> network configuration` map
was being built *after* the state update, so it was not ready at the
time of the `stateChange` event.

The fix involves moving this map building inside the state update, so
that its built by the time `stateChange` fires. But also requires deep
cloning the state before building the map from it. Otherwise we get
`Cannot perform 'get' on a proxy that has been revoked` when referencing
the ephemeral `state` lambda.


## References

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### `@metamask/network-controller`

- **FIXED**: A race condition when calling
`getNetworkConfigurationByNetworkClientId` in response to a
`stateChange` event adding a new endpoint to a network.


## Checklist

- [ ] I've updated the test suite for new or updated code as appropriate
- [ ] I've updated documentation (JSDoc, Markdown, etc.) for new or
updated code as appropriate
- [ ] I've highlighted breaking changes using the "BREAKING" category
above as appropriate
- [ ] I've prepared draft pull requests for clients and consumer
packages to resolve any breaking changes

packages/network-controller/src/NetworkController.ts

@@ -22,6 +22,7 @@ import type { Hex } from '@metamask/utils';
 import { hasProperty, isPlainObject, isStrictHexString } from '@metamask/utils';
 import deepEqual from 'fast-deep-equal';
 import type { Draft } from 'immer';
+import { cloneDeep } from 'lodash';
 import type { Logger } from 'loglevel';
 import { createSelector } from 'reselect';
 import * as URI from 'uri-js';
@@ -1636,11 +1637,6 @@ export class NetworkController extends BaseController<
       });
     });
 
-    this.#networkConfigurationsByNetworkClientId =
-      buildNetworkConfigurationsByNetworkClientId(
-        this.state.networkConfigurationsByChainId,
-      );
-
     this.messagingSystem.publish(
       `${controllerName}:networkAdded`,
       newNetworkConfiguration,
@@ -1919,11 +1915,6 @@ export class NetworkController extends BaseController<
       });
     }
 
-    this.#networkConfigurationsByNetworkClientId =
-      buildNetworkConfigurationsByNetworkClientId(
-        this.state.networkConfigurationsByChainId,
-      );
-
     this.#unregisterNetworkClientsAsNeeded({
       networkClientOperations,
       autoManagedNetworkClientRegistry,
@@ -1983,11 +1974,6 @@ export class NetworkController extends BaseController<
       });
     });
 
-    this.#networkConfigurationsByNetworkClientId =
-      buildNetworkConfigurationsByNetworkClientId(
-        this.state.networkConfigurationsByChainId,
-      );
-
     this.messagingSystem.publish(
       'NetworkController:networkRemoved',
       existingNetworkConfiguration,
@@ -2500,6 +2486,11 @@ export class NetworkController extends BaseController<
       state.networkConfigurationsByChainId[args.networkFields.chainId] =
         args.networkConfigurationToPersist;
     }
+
+    this.#networkConfigurationsByNetworkClientId =
+      buildNetworkConfigurationsByNetworkClientId(
+        cloneDeep(state.networkConfigurationsByChainId),
+      );
   }
 
   /**

packages/network-controller/tests/NetworkController.test.ts

@@ -11338,6 +11338,60 @@ describe('NetworkController', () => {
         });
       });
     });
+
+    it('allows calling `getNetworkConfigurationByNetworkClientId` when subscribing to state changes containing new endpoints', async () => {
+      const network = buildCustomNetworkConfiguration({
+        chainId: '0x1' as Hex,
+        name: 'mainnet',
+        nativeCurrency: 'ETH',
+        blockExplorerUrls: [],
+        defaultRpcEndpointIndex: 0,
+        rpcEndpoints: [
+          {
+            type: RpcEndpointType.Custom,
+            url: 'https://test.endpoint/1',
+            networkClientId: 'client1',
+          },
+        ],
+      });
+
+      await withController(
+        {
+          state: {
+            selectedNetworkClientId: 'client1',
+            networkConfigurationsByChainId: { '0x1': network },
+          },
+        },
+        async ({ controller, messenger }) => {
+
+          const stateChangePromise = new Promise<NetworkConfiguration | undefined>((resolve) => {
+            messenger.subscribe('NetworkController:stateChange', (state) => {
+              const { networkClientId } =
+                state.networkConfigurationsByChainId['0x1'].rpcEndpoints[1];
+
+              resolve(
+                controller.getNetworkConfigurationByNetworkClientId(networkClientId),
+              );
+            });
+          });
+
+          // Add a new endpoint
+          await controller.updateNetwork('0x1', {
+            ...network,
+            rpcEndpoints: [
+              ...network.rpcEndpoints,
+              {
+                type: RpcEndpointType.Custom,
+                url: 'https://test.endpoint/2',
+              },
+            ],
+          });
+
+          const networkConfiguration = await stateChangePromise;
+          expect(networkConfiguration).toBeDefined();
+        },
+      );
+    });
   });
 
   describe('removeNetwork', () => {