fix: confusing error message when using wrong password (#5627)

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When calling `submitPassword` with the wrong password, a confusing error
is shown instead of `Incorrect password`. This is due to the recently
added metadata length check in `#restoreSerializedKeyrings`, which
doesn't match the correct behavior when `isUnlocked = true`.

We can move the metadata length check to `#unlockKeyrings`, so that it
will be skipped everytime the controller is locked

## References

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* Related to MetaMask/metamask-extension#31436

## Changelog

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Changelog updated in the PR

## 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 communicated my changes to consumers by [updating changelogs
for packages I've
changed](https://github.com/MetaMask/core/tree/main/docs/contributing.md#updating-changelogs),
highlighting breaking changes as necessary
- [ ] I've prepared draft pull requests for clients and consumer
packages to resolve any breaking changes

Author: mikesposito

packages/keyring-controller/CHANGELOG.md

@@ -12,6 +12,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `ExportableKeyEncryptor` is now a generic type with a type parameter `EncryptionKey` ([#5395](https://github.com/MetaMask/core/pull/5395))
   - The type parameter defaults to `unknown`
 
+### Fixed
+
+- Fixed wrong error message thrown when using the wrong password ([#5627](https://github.com/MetaMask/core/pull/5627))
+
 ## [21.0.2]
 
 ### Changed

packages/keyring-controller/src/KeyringController.test.ts

@@ -2734,6 +2734,21 @@ describe('KeyringController', () => {
               expect(controller.state.encryptionSalt).toBeDefined();
             });
           });
+
+        it('should throw error when using the wrong password', async () => {
+          await withController(
+            {
+              skipVaultCreation: true,
+              cacheEncryptionKey,
+              state: { vault: 'my vault' },
+            },
+            async ({ controller }) => {
+              await expect(
+                controller.submitPassword('wrong password'),
+              ).rejects.toThrow('Incorrect password.');
+            },
+          );
+        });
       }),
     );
   });

packages/keyring-controller/src/KeyringController.ts

@@ -2159,10 +2159,6 @@ export class KeyringController extends BaseController<
     for (const serializedKeyring of serializedKeyrings) {
       await this.#restoreKeyring(serializedKeyring);
     }
-
-    if (this.#keyrings.length !== this.#keyringsMetadata.length) {
-      throw new Error(KeyringControllerError.KeyringMetadataLengthMismatch);
-    }
   }
 
   /**
@@ -2240,6 +2236,13 @@ export class KeyringController extends BaseController<
       }
 
       await this.#restoreSerializedKeyrings(vault);
+
+      // The keyrings array and the keyringsMetadata array should
+      // always have the same length while the controller is unlocked.
+      if (this.#keyrings.length !== this.#keyringsMetadata.length) {
+        throw new Error(KeyringControllerError.KeyringMetadataLengthMismatch);
+      }
+
       const updatedKeyrings = await this.#getUpdatedKeyrings();
 
       this.update((state) => {