From 3344a44dc6ef6b7d0de53d4f185ed6dba785a209 Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 7 Feb 2024 13:59:59 -0500
Subject: [PATCH 01/25] Add `@metamask/utils` to composable-controller deps

---
 packages/composable-controller/package.json | 3 ++-
 yarn.lock                                   | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/composable-controller/package.json b/packages/composable-controller/package.json
index 432b6b3c03f..d1e56cd004f 100644
--- a/packages/composable-controller/package.json
+++ b/packages/composable-controller/package.json
@@ -31,7 +31,8 @@
     "test:watch": "jest --watch"
   },
   "dependencies": {
-    "@metamask/base-controller": "^4.1.1"
+    "@metamask/base-controller": "^4.1.1",
+    "@metamask/utils": "^8.3.0"
   },
   "devDependencies": {
     "@metamask/auto-changelog": "^3.4.4",
diff --git a/yarn.lock b/yarn.lock
index fcc17862f20..4305ac86e80 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1708,6 +1708,7 @@ __metadata:
   dependencies:
     "@metamask/auto-changelog": ^3.4.4
     "@metamask/base-controller": ^4.1.1
+    "@metamask/utils": ^8.3.0
     "@types/jest": ^27.4.1
     deepmerge: ^4.2.2
     immer: ^9.0.6

From f50716abab684be10abba5b4b42d1d0011c8ee81 Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 7 Feb 2024 20:32:28 -0500
Subject: [PATCH 02/25] Define and apply `isBaseController` type guard

---
 .../src/ComposableController.ts               | 34 ++++++++++++++-----
 1 file changed, 26 insertions(+), 8 deletions(-)

diff --git a/packages/composable-controller/src/ComposableController.ts b/packages/composable-controller/src/ComposableController.ts
index 6d4f6eb7d83..15d4d7f3360 100644
--- a/packages/composable-controller/src/ComposableController.ts
+++ b/packages/composable-controller/src/ComposableController.ts
@@ -36,6 +36,23 @@ function isBaseControllerV1(
   return controller instanceof BaseControllerV1;
 }
 
+/**
+ * Determines if the given controller is an instance of BaseController
+ * @param controller - Controller instance to check
+ * @returns True if the controller is an instance of BaseController
+ */
+function isBaseController(
+  controller: ControllerInstance,
+): controller is BaseController<never, never, never> {
+  return (
+    'name' in controller &&
+    typeof controller.name === 'string' &&
+    'state' in controller &&
+    typeof controller.state === 'object' &&
+    controller instanceof BaseController
+  );
+}
+
 export type ComposableControllerState = {
   [name: string]: ControllerInstance['state'];
 };
@@ -113,15 +130,16 @@ export class ComposableController extends BaseController<
           [name]: childState,
         }));
       });
+    } else if (isBaseController(controller)) {
+      this.messagingSystem.subscribe(`${name}:stateChange`, (childState) => {
+        this.update((state) => ({
+          ...state,
+          [name]: childState,
+        }));
+      });
     } else {
-      this.messagingSystem.subscribe(
-        `${String(name)}:stateChange`,
-        (childState: Record<string, unknown>) => {
-          this.update((state) => ({
-            ...state,
-            [name]: childState,
-          }));
-        },
+      throw new Error(
+        'Invalid controller: controller must extend from BaseController or BaseControllerV1',
       );
     }
   }

From 7be4f2821411df1e1fc28f5e032206b56906e817 Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 7 Feb 2024 20:34:49 -0500
Subject: [PATCH 03/25] test: Add test for composing a non-controller

---
 .../src/ComposableController.test.ts          | 31 +++++++++++++++++++
 packages/composable-controller/tsconfig.json  |  3 ++
 2 files changed, 34 insertions(+)

diff --git a/packages/composable-controller/src/ComposableController.test.ts b/packages/composable-controller/src/ComposableController.test.ts
index 4e5d944fa1f..41b6e47f639 100644
--- a/packages/composable-controller/src/ComposableController.test.ts
+++ b/packages/composable-controller/src/ComposableController.test.ts
@@ -10,6 +10,7 @@ import {
 import type { Patch } from 'immer';
 import * as sinon from 'sinon';
 
+import { JsonRpcEngine } from '../../json-rpc-engine/src/JsonRpcEngine';
 import type { ComposableControllerStateChangeEvent } from './ComposableController';
 import { ComposableController } from './ComposableController';
 
@@ -335,5 +336,35 @@ describe('ComposableController', () => {
           }),
       ).toThrow('Messaging system is required');
     });
+
+    it('should throw if attempting to compose a controller that does not extend from BaseController', () => {
+      const notController = new JsonRpcEngine();
+      const controllerMessenger = new ControllerMessenger<
+        never,
+        FooControllerEvent
+      >();
+      const fooControllerMessenger = controllerMessenger.getRestricted<
+        'FooController',
+        never,
+        never
+      >({
+        name: 'FooController',
+      });
+      const fooController = new FooController(fooControllerMessenger);
+      const composableControllerMessenger = controllerMessenger.getRestricted({
+        name: 'ComposableController',
+        allowedEvents: ['FooController:stateChange'],
+      });
+      expect(
+        () =>
+          new ComposableController({
+            // @ts-expect-error - Suppressing type error to test for runtime error handling
+            controllers: [notController, fooController],
+            messenger: composableControllerMessenger,
+          }),
+      ).toThrow(
+        'Invalid controller: controller must extend from BaseController or BaseControllerV1',
+      );
+    });
   });
 });
diff --git a/packages/composable-controller/tsconfig.json b/packages/composable-controller/tsconfig.json
index f2d7b67ff66..cc814f313b7 100644
--- a/packages/composable-controller/tsconfig.json
+++ b/packages/composable-controller/tsconfig.json
@@ -6,6 +6,9 @@
   "references": [
     {
       "path": "../base-controller"
+    },
+    {
+      "path": "../json-rpc-engine"
     }
   ],
   "include": ["../../types", "./src"]

From 416382eb7674911a2b00bd9eb3e896b61c2934df Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 7 Feb 2024 20:35:35 -0500
Subject: [PATCH 04/25] Improve BaseControllerV1 typing, type guard, comments

---
 .../src/ComposableController.ts               | 29 +++++++++++++++----
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/packages/composable-controller/src/ComposableController.ts b/packages/composable-controller/src/ComposableController.ts
index 15d4d7f3360..2ba9b9d5e25 100644
--- a/packages/composable-controller/src/ComposableController.ts
+++ b/packages/composable-controller/src/ComposableController.ts
@@ -2,6 +2,8 @@ import { BaseController, BaseControllerV1 } from '@metamask/base-controller';
 import type {
   ControllerStateChangeEvent,
   RestrictedControllerMessenger,
+  BaseState,
+  BaseConfig,
 } from '@metamask/base-controller';
 
 export const controllerName = 'ComposableController';
@@ -14,7 +16,7 @@ export const controllerName = 'ComposableController';
  * that we use in the ComposableController (name and state).
  */
 type ControllerInstance =
-  // TODO: Replace `any` with type
+  // As explained above, `any` is used to include all `BaseControllerV1` instances.
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   BaseControllerV1<any, any> | { name: string; state: Record<string, unknown> };
 
@@ -30,10 +32,21 @@ export type ControllerList = ControllerInstance[];
  */
 function isBaseControllerV1(
   controller: ControllerInstance,
-  // TODO: Replace `any` with type
-  // eslint-disable-next-line @typescript-eslint/no-explicit-any
-): controller is BaseControllerV1<any, any> {
-  return controller instanceof BaseControllerV1;
+): controller is BaseControllerV1<
+  BaseConfig & Record<string, unknown>,
+  BaseState & Record<string, unknown>
+> {
+  return (
+    'name' in controller &&
+    typeof controller.name === 'string' &&
+    'defaultConfig' in controller &&
+    typeof controller.defaultConfig === 'object' &&
+    'defaultState' in controller &&
+    typeof controller.defaultState === 'object' &&
+    'disabled' in controller &&
+    typeof controller.disabled === 'boolean' &&
+    controller instanceof BaseControllerV1
+  );
 }
 
 /**
@@ -54,7 +67,11 @@ function isBaseController(
 }
 
 export type ComposableControllerState = {
-  [name: string]: ControllerInstance['state'];
+  // `any` is used here to disable the `BaseController` type constraint which expects state properties to extend `Record<string, Json>`.
+  // `ComposableController` state needs to accommodate `BaseControllerV1` state objects, and there is no straightforward way
+  // to include objects in `BaseController` state when they may have properties that are wider than `Json`.
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  [name: string]: Record<string, any>;
 };
 
 export type ComposableControllerStateChangeEvent = ControllerStateChangeEvent<

From 7b9e33a2baff855dd7c88a3d60501921018d7a37 Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 7 Feb 2024 20:36:19 -0500
Subject: [PATCH 05/25] Remove unused `#controllers` class field

---
 .../composable-controller/src/ComposableController.ts  | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/packages/composable-controller/src/ComposableController.ts b/packages/composable-controller/src/ComposableController.ts
index 2ba9b9d5e25..e88484d18a8 100644
--- a/packages/composable-controller/src/ComposableController.ts
+++ b/packages/composable-controller/src/ComposableController.ts
@@ -97,8 +97,6 @@ export class ComposableController extends BaseController<
   ComposableControllerState,
   ComposableControllerMessenger
 > {
-  readonly #controllers: ControllerList = [];
-
   /**
    * Creates a ComposableController instance.
    *
@@ -127,19 +125,19 @@ export class ComposableController extends BaseController<
       messenger,
     });
 
-    this.#controllers = controllers;
-    this.#controllers.forEach((controller) =>
+    controllers.forEach((controller) =>
       this.#updateChildController(controller),
     );
   }
 
   /**
-   * Adds a child controller instance to composable controller state,
-   * or updates the state of a child controller.
+   * Constructor helper that adds a child controller instance to composable controller state
+   * and subscribes to child controller state changes.
    * @param controller - Controller instance to update
    */
   #updateChildController(controller: ControllerInstance): void {
     const { name } = controller;
+
     if (isBaseControllerV1(controller)) {
       controller.subscribe((childState) => {
         this.update((state) => ({

From d4a8161b18004ffc2f2c69d03b12f93ff4f8a4cf Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 7 Feb 2024 20:54:48 -0500
Subject: [PATCH 06/25] Export base-controller type guards

---
 packages/composable-controller/src/ComposableController.ts | 4 ++--
 packages/composable-controller/src/index.ts                | 6 +++++-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/packages/composable-controller/src/ComposableController.ts b/packages/composable-controller/src/ComposableController.ts
index e88484d18a8..620389b3069 100644
--- a/packages/composable-controller/src/ComposableController.ts
+++ b/packages/composable-controller/src/ComposableController.ts
@@ -30,7 +30,7 @@ export type ControllerList = ControllerInstance[];
  * @param controller - Controller instance to check
  * @returns True if the controller is an instance of BaseControllerV1
  */
-function isBaseControllerV1(
+export function isBaseControllerV1(
   controller: ControllerInstance,
 ): controller is BaseControllerV1<
   BaseConfig & Record<string, unknown>,
@@ -54,7 +54,7 @@ function isBaseControllerV1(
  * @param controller - Controller instance to check
  * @returns True if the controller is an instance of BaseController
  */
-function isBaseController(
+export function isBaseController(
   controller: ControllerInstance,
 ): controller is BaseController<never, never, never> {
   return (
diff --git a/packages/composable-controller/src/index.ts b/packages/composable-controller/src/index.ts
index da2d27e177e..5fc5a803c5d 100644
--- a/packages/composable-controller/src/index.ts
+++ b/packages/composable-controller/src/index.ts
@@ -5,4 +5,8 @@ export type {
   ComposableControllerEvents,
   ComposableControllerMessenger,
 } from './ComposableController';
-export { ComposableController } from './ComposableController';
+export {
+  ComposableController,
+  isBaseController,
+  isBaseControllerV1,
+} from './ComposableController';

From c762c6eaf2482a95a04fc68856f3d4501f5369be Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 7 Feb 2024 22:02:32 -0500
Subject: [PATCH 07/25] Remove deprecated `subscribe` property from
 BaseControllerV2

---
 packages/base-controller/src/BaseControllerV2.ts | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/packages/base-controller/src/BaseControllerV2.ts b/packages/base-controller/src/BaseControllerV2.ts
index 32467cf0d43..23b5c22f4c6 100644
--- a/packages/base-controller/src/BaseControllerV2.ts
+++ b/packages/base-controller/src/BaseControllerV2.ts
@@ -113,17 +113,6 @@ export class BaseController<
 
   public readonly metadata: StateMetadata<ControllerState>;
 
-  /**
-   * The existence of the `subscribe` property is how the ComposableController used to detect
-   * whether a controller extends the old BaseController or the new one. We set it to `undefined` here to
-   * ensure the ComposableController never mistakes them for an older style controller.
-   *
-   * This property is no longer used, and will be removed in a future release.
-   *
-   * @deprecated This will be removed in a future release
-   */
-  public readonly subscribe: undefined;
-
   /**
    * Creates a BaseController instance.
    *

From 53be42748478d11da750ceb251b246ef6f634b9c Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 7 Feb 2024 22:07:26 -0500
Subject: [PATCH 08/25] Use `Record<string, Json>` typing for BaseControllerV2
 state objects

---
 .../composable-controller/src/ComposableController.ts    | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/packages/composable-controller/src/ComposableController.ts b/packages/composable-controller/src/ComposableController.ts
index 620389b3069..1452dd764e8 100644
--- a/packages/composable-controller/src/ComposableController.ts
+++ b/packages/composable-controller/src/ComposableController.ts
@@ -5,6 +5,7 @@ import type {
   BaseState,
   BaseConfig,
 } from '@metamask/base-controller';
+import type { Json } from '@metamask/utils';
 
 export const controllerName = 'ComposableController';
 
@@ -18,7 +19,7 @@ export const controllerName = 'ComposableController';
 type ControllerInstance =
   // As explained above, `any` is used to include all `BaseControllerV1` instances.
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  BaseControllerV1<any, any> | { name: string; state: Record<string, unknown> };
+  BaseControllerV1<any, any> | { name: string; state: Record<string, Json> };
 
 /**
  * List of child controller instances
@@ -68,15 +69,14 @@ export function isBaseController(
 
 export type ComposableControllerState = {
   // `any` is used here to disable the `BaseController` type constraint which expects state properties to extend `Record<string, Json>`.
-  // `ComposableController` state needs to accommodate `BaseControllerV1` state objects, and there is no straightforward way
-  // to include objects in `BaseController` state when they may have properties that are wider than `Json`.
+  // `ComposableController` state needs to accommodate `BaseControllerV1` state objects that may have properties wider than `Json`.
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   [name: string]: Record<string, any>;
 };
 
 export type ComposableControllerStateChangeEvent = ControllerStateChangeEvent<
   typeof controllerName,
-  ComposableControllerState
+  Record<string, Json | (BaseState & Record<string, unknown>)>
 >;
 
 export type ComposableControllerEvents = ComposableControllerStateChangeEvent;
@@ -137,7 +137,6 @@ export class ComposableController extends BaseController<
    */
   #updateChildController(controller: ControllerInstance): void {
     const { name } = controller;
-
     if (isBaseControllerV1(controller)) {
       controller.subscribe((childState) => {
         this.update((state) => ({

From 4f5484122c9e73b3dbf4e37951f7ac151f4198fe Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 7 Feb 2024 22:08:23 -0500
Subject: [PATCH 09/25] Use generic argument for typing `reduce`

---
 .../composable-controller/src/ComposableController.ts    | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/packages/composable-controller/src/ComposableController.ts b/packages/composable-controller/src/ComposableController.ts
index 1452dd764e8..d55993a82e2 100644
--- a/packages/composable-controller/src/ComposableController.ts
+++ b/packages/composable-controller/src/ComposableController.ts
@@ -119,9 +119,12 @@ export class ComposableController extends BaseController<
     super({
       name: controllerName,
       metadata: {},
-      state: controllers.reduce((state, controller) => {
-        return { ...state, [controller.name]: controller.state };
-      }, {} as ComposableControllerState),
+      state: controllers.reduce<ComposableControllerState>(
+        (state, controller) => {
+          return { ...state, [controller.name]: controller.state };
+        },
+        {},
+      ),
       messenger,
     });
 

From f4530ab24a22686cdaa98ebc662d9960bce04a6c Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 7 Feb 2024 22:13:10 -0500
Subject: [PATCH 10/25] Update CHANGELOGs

---
 packages/base-controller/CHANGELOG.md       | 5 +++++
 packages/composable-controller/CHANGELOG.md | 9 +++++++++
 2 files changed, 14 insertions(+)

diff --git a/packages/base-controller/CHANGELOG.md b/packages/base-controller/CHANGELOG.md
index 52ee840f1d7..bda0315b5e4 100644
--- a/packages/base-controller/CHANGELOG.md
+++ b/packages/base-controller/CHANGELOG.md
@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Removed
+
+- **BREAKING:** Remove the deprecated `subscribe` class field from `BaseControllerV2` ([#3904](https://github.com/MetaMask/core/pull/3904))
+  - Replaced by the `isBaseController` type guard in `@metamask/composable-controller`.
+
 ## [4.1.1]
 
 ### Changed
diff --git a/packages/composable-controller/CHANGELOG.md b/packages/composable-controller/CHANGELOG.md
index 26688cf855f..d96288facb4 100644
--- a/packages/composable-controller/CHANGELOG.md
+++ b/packages/composable-controller/CHANGELOG.md
@@ -7,6 +7,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- **BREAKING:** Add `@metamask/utils` ^8.3.0 as a dependency. ([#3904](https://github.com/MetaMask/core/pull/3904))
+- Add exports `isBaseControllerV1` and `isBaseController`, which are type guards for validating controller instances ([#3904](https://github.com/MetaMask/core/pull/3904))
+
+### Changed
+
+- Throws an error if a non-controller is passed into the `controllers` constructor option ([#3904](https://github.com/MetaMask/core/pull/3904))
+
 ## [5.0.1]
 
 ### Changed

From 724f80eb2b37ffb8f8000e6b80bf837f9be59343 Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 7 Feb 2024 23:10:43 -0500
Subject: [PATCH 11/25] Refactor messenger typing for controller events and
 allowed events

---
 .../src/ComposableController.test.ts            | 17 ++++++++++-------
 .../src/ComposableController.ts                 | 15 +++++++++++----
 2 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/packages/composable-controller/src/ComposableController.test.ts b/packages/composable-controller/src/ComposableController.test.ts
index 41b6e47f639..6087de8313e 100644
--- a/packages/composable-controller/src/ComposableController.test.ts
+++ b/packages/composable-controller/src/ComposableController.test.ts
@@ -11,7 +11,7 @@ import type { Patch } from 'immer';
 import * as sinon from 'sinon';
 
 import { JsonRpcEngine } from '../../json-rpc-engine/src/JsonRpcEngine';
-import type { ComposableControllerStateChangeEvent } from './ComposableController';
+import type { ComposableControllerEvents } from './ComposableController';
 import { ComposableController } from './ComposableController';
 
 // Mock BaseController classes
@@ -107,7 +107,10 @@ describe('ComposableController', () => {
 
   describe('BaseControllerV1', () => {
     it('should compose controller state', () => {
-      const composableMessenger = new ControllerMessenger().getRestricted({
+      const composableMessenger = new ControllerMessenger<
+        never,
+        ComposableControllerEvents
+      >().getRestricted({
         name: 'ComposableController',
       });
       const controller = new ComposableController({
@@ -124,7 +127,7 @@ describe('ComposableController', () => {
     it('should notify listeners of nested state change', () => {
       const controllerMessenger = new ControllerMessenger<
         never,
-        ComposableControllerStateChangeEvent
+        ComposableControllerEvents
       >();
       const composableMessenger = controllerMessenger.getRestricted({
         name: 'ComposableController',
@@ -177,7 +180,7 @@ describe('ComposableController', () => {
     it('should notify listeners of nested state change', () => {
       const controllerMessenger = new ControllerMessenger<
         never,
-        ComposableControllerStateChangeEvent | FooControllerEvent
+        ComposableControllerEvents | FooControllerEvent
       >();
       const fooControllerMessenger = controllerMessenger.getRestricted<
         'FooController',
@@ -241,7 +244,7 @@ describe('ComposableController', () => {
       const barController = new BarController();
       const controllerMessenger = new ControllerMessenger<
         never,
-        ComposableControllerStateChangeEvent | FooControllerEvent
+        ComposableControllerEvents | FooControllerEvent
       >();
       const fooControllerMessenger = controllerMessenger.getRestricted<
         'FooController',
@@ -281,7 +284,7 @@ describe('ComposableController', () => {
       const barController = new BarController();
       const controllerMessenger = new ControllerMessenger<
         never,
-        ComposableControllerStateChangeEvent | FooControllerEvent
+        ComposableControllerEvents | FooControllerEvent
       >();
       const fooControllerMessenger = controllerMessenger.getRestricted<
         'FooController',
@@ -337,7 +340,7 @@ describe('ComposableController', () => {
       ).toThrow('Messaging system is required');
     });
 
-    it('should throw if attempting to compose a controller that does not extend from BaseController', () => {
+    it('should throw if composing a controller that does not extend from BaseController', () => {
       const notController = new JsonRpcEngine();
       const controllerMessenger = new ControllerMessenger<
         never,
diff --git a/packages/composable-controller/src/ComposableController.ts b/packages/composable-controller/src/ComposableController.ts
index d55993a82e2..d796c76898a 100644
--- a/packages/composable-controller/src/ComposableController.ts
+++ b/packages/composable-controller/src/ComposableController.ts
@@ -76,17 +76,24 @@ export type ComposableControllerState = {
 
 export type ComposableControllerStateChangeEvent = ControllerStateChangeEvent<
   typeof controllerName,
-  Record<string, Json | (BaseState & Record<string, unknown>)>
+  Record<string, unknown>
 >;
 
 export type ComposableControllerEvents = ComposableControllerStateChangeEvent;
 
+type AnyControllerStateChangeEvent = ControllerStateChangeEvent<
+  string,
+  Record<string, unknown>
+>;
+
+type AllowedEvents = AnyControllerStateChangeEvent;
+
 export type ComposableControllerMessenger = RestrictedControllerMessenger<
   typeof controllerName,
   never,
-  ControllerStateChangeEvent<string, Record<string, unknown>>,
-  string,
-  string
+  ComposableControllerEvents | AllowedEvents,
+  never,
+  AllowedEvents['type']
 >;
 
 /**

From 48669b20a8d9a57254a6589209fcf20c309e6e36 Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 7 Feb 2024 23:11:17 -0500
Subject: [PATCH 12/25] Add `isValidJson` check for child state from
 BaseControllerV2 controllers

---
 .../src/ComposableController.ts                      | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/packages/composable-controller/src/ComposableController.ts b/packages/composable-controller/src/ComposableController.ts
index d796c76898a..7e85c72e66b 100644
--- a/packages/composable-controller/src/ComposableController.ts
+++ b/packages/composable-controller/src/ComposableController.ts
@@ -5,7 +5,7 @@ import type {
   BaseState,
   BaseConfig,
 } from '@metamask/base-controller';
-import type { Json } from '@metamask/utils';
+import { isValidJson, type Json } from '@metamask/utils';
 
 export const controllerName = 'ComposableController';
 
@@ -156,10 +156,12 @@ export class ComposableController extends BaseController<
       });
     } else if (isBaseController(controller)) {
       this.messagingSystem.subscribe(`${name}:stateChange`, (childState) => {
-        this.update((state) => ({
-          ...state,
-          [name]: childState,
-        }));
+        if (isValidJson(childState)) {
+          this.update((state) => ({
+            ...state,
+            [name]: childState,
+          }));
+        }
       });
     } else {
       throw new Error(

From 1069fa40a96996373e99a011326bbcde0070ff16 Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 7 Feb 2024 23:22:36 -0500
Subject: [PATCH 13/25] Update CHANGELOG

---
 packages/composable-controller/CHANGELOG.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/packages/composable-controller/CHANGELOG.md b/packages/composable-controller/CHANGELOG.md
index d96288facb4..369ca9143ef 100644
--- a/packages/composable-controller/CHANGELOG.md
+++ b/packages/composable-controller/CHANGELOG.md
@@ -16,6 +16,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Throws an error if a non-controller is passed into the `controllers` constructor option ([#3904](https://github.com/MetaMask/core/pull/3904))
 
+### Removed
+
+- **BREAKING:** The `AllowedActions` parameter of the `ComposableControllerMessenger` type is narrowed from `string` to `never`, as `ComposableController` does not use any external controller actions. ([#3904](https://github.com/MetaMask/core/pull/3904))
+
 ## [5.0.1]
 
 ### Changed

From d4cf789a94bdf8d177d69650deafa1e7c2eb038f Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Thu, 8 Feb 2024 14:18:14 -0500
Subject: [PATCH 14/25] Add `@metamask/json-rpc-engine` as devDep

---
 packages/composable-controller/package.json | 1 +
 yarn.lock                                   | 1 +
 2 files changed, 2 insertions(+)

diff --git a/packages/composable-controller/package.json b/packages/composable-controller/package.json
index d1e56cd004f..53ad6a93be6 100644
--- a/packages/composable-controller/package.json
+++ b/packages/composable-controller/package.json
@@ -36,6 +36,7 @@
   },
   "devDependencies": {
     "@metamask/auto-changelog": "^3.4.4",
+    "@metamask/json-rpc-engine": "^7.3.2",
     "@types/jest": "^27.4.1",
     "deepmerge": "^4.2.2",
     "immer": "^9.0.6",
diff --git a/yarn.lock b/yarn.lock
index 4305ac86e80..17c75c30e27 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1708,6 +1708,7 @@ __metadata:
   dependencies:
     "@metamask/auto-changelog": ^3.4.4
     "@metamask/base-controller": ^4.1.1
+    "@metamask/json-rpc-engine": ^7.3.2
     "@metamask/utils": ^8.3.0
     "@types/jest": ^27.4.1
     deepmerge: ^4.2.2

From 559b4a1e211c78c84e70b6de7bc96d63fc9bdbec Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Tue, 20 Feb 2024 15:02:05 -0500
Subject: [PATCH 15/25] Revert "Remove deprecated `subscribe` property from
 BaseControllerV2"

This reverts commit 280e8e4f764fe5682d3bff08558441d741782d2f.
---
 packages/base-controller/src/BaseControllerV2.ts | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/packages/base-controller/src/BaseControllerV2.ts b/packages/base-controller/src/BaseControllerV2.ts
index 23b5c22f4c6..32467cf0d43 100644
--- a/packages/base-controller/src/BaseControllerV2.ts
+++ b/packages/base-controller/src/BaseControllerV2.ts
@@ -113,6 +113,17 @@ export class BaseController<
 
   public readonly metadata: StateMetadata<ControllerState>;
 
+  /**
+   * The existence of the `subscribe` property is how the ComposableController used to detect
+   * whether a controller extends the old BaseController or the new one. We set it to `undefined` here to
+   * ensure the ComposableController never mistakes them for an older style controller.
+   *
+   * This property is no longer used, and will be removed in a future release.
+   *
+   * @deprecated This will be removed in a future release
+   */
+  public readonly subscribe: undefined;
+
   /**
    * Creates a BaseController instance.
    *

From 71fc9a401c1bd6e38674313bf189b1726cc6e9a2 Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Tue, 20 Feb 2024 12:06:34 -0800
Subject: [PATCH 16/25] Update packages/base-controller/CHANGELOG.md

---
 packages/base-controller/CHANGELOG.md | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/packages/base-controller/CHANGELOG.md b/packages/base-controller/CHANGELOG.md
index bda0315b5e4..52ee840f1d7 100644
--- a/packages/base-controller/CHANGELOG.md
+++ b/packages/base-controller/CHANGELOG.md
@@ -7,11 +7,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
-### Removed
-
-- **BREAKING:** Remove the deprecated `subscribe` class field from `BaseControllerV2` ([#3904](https://github.com/MetaMask/core/pull/3904))
-  - Replaced by the `isBaseController` type guard in `@metamask/composable-controller`.
-
 ## [4.1.1]
 
 ### Changed

From f7097cb295ac8fd74a9826df0a77071e50f1f417 Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Tue, 20 Feb 2024 22:41:39 -0500
Subject: [PATCH 17/25] Add TODOs for removing `BaseControllerV1` related
 features once all controllers have migrated to V2

---
 packages/composable-controller/src/ComposableController.ts | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/packages/composable-controller/src/ComposableController.ts b/packages/composable-controller/src/ComposableController.ts
index 7e85c72e66b..8ef24a758f2 100644
--- a/packages/composable-controller/src/ComposableController.ts
+++ b/packages/composable-controller/src/ComposableController.ts
@@ -18,6 +18,7 @@ export const controllerName = 'ComposableController';
  */
 type ControllerInstance =
   // As explained above, `any` is used to include all `BaseControllerV1` instances.
+  // TODO: Remove first union member once `BaseControllerV2` migrations are completed for all controllers.
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   BaseControllerV1<any, any> | { name: string; state: Record<string, Json> };
 
@@ -30,6 +31,7 @@ export type ControllerList = ControllerInstance[];
  * Determines if the given controller is an instance of BaseControllerV1
  * @param controller - Controller instance to check
  * @returns True if the controller is an instance of BaseControllerV1
+ * TODO: Deprecate once `BaseControllerV2` migrations are completed for all controllers.
  */
 export function isBaseControllerV1(
   controller: ControllerInstance,
@@ -70,6 +72,7 @@ export function isBaseController(
 export type ComposableControllerState = {
   // `any` is used here to disable the `BaseController` type constraint which expects state properties to extend `Record<string, Json>`.
   // `ComposableController` state needs to accommodate `BaseControllerV1` state objects that may have properties wider than `Json`.
+  // TODO: Replace `any` with `Json` once `BaseControllerV2` migrations are completed for all controllers.
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   [name: string]: Record<string, any>;
 };
@@ -144,6 +147,7 @@ export class ComposableController extends BaseController<
    * Constructor helper that adds a child controller instance to composable controller state
    * and subscribes to child controller state changes.
    * @param controller - Controller instance to update
+   * TODO: Remove `isBaseControllerV1` branch once `BaseControllerV2` migrations are completed for all controllers.
    */
   #updateChildController(controller: ControllerInstance): void {
     const { name } = controller;

From ada78a2b1960d2f9b65802e114b69a382b449991 Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Tue, 20 Feb 2024 23:30:55 -0500
Subject: [PATCH 18/25] Remove `ControllerList` type, add
 `BaseControllerV{1,2}Instance` types

---
 packages/composable-controller/CHANGELOG.md   |  3 ++-
 .../src/ComposableController.ts               | 20 ++++++++++---------
 packages/composable-controller/src/index.ts   |  1 -
 3 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/packages/composable-controller/CHANGELOG.md b/packages/composable-controller/CHANGELOG.md
index 369ca9143ef..401ebee7b27 100644
--- a/packages/composable-controller/CHANGELOG.md
+++ b/packages/composable-controller/CHANGELOG.md
@@ -9,16 +9,17 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
-- **BREAKING:** Add `@metamask/utils` ^8.3.0 as a dependency. ([#3904](https://github.com/MetaMask/core/pull/3904))
 - Add exports `isBaseControllerV1` and `isBaseController`, which are type guards for validating controller instances ([#3904](https://github.com/MetaMask/core/pull/3904))
 
 ### Changed
 
+- **BREAKING:** Add `@metamask/utils` ^8.3.0 as a dependency. ([#3904](https://github.com/MetaMask/core/pull/3904))
 - Throws an error if a non-controller is passed into the `controllers` constructor option ([#3904](https://github.com/MetaMask/core/pull/3904))
 
 ### Removed
 
 - **BREAKING:** The `AllowedActions` parameter of the `ComposableControllerMessenger` type is narrowed from `string` to `never`, as `ComposableController` does not use any external controller actions. ([#3904](https://github.com/MetaMask/core/pull/3904))
+- **BREAKING:** Remove `ControllerList` as an exported type. ([#3904](https://github.com/MetaMask/core/pull/3904))
 
 ## [5.0.1]
 
diff --git a/packages/composable-controller/src/ComposableController.ts b/packages/composable-controller/src/ComposableController.ts
index 8ef24a758f2..456539f7da4 100644
--- a/packages/composable-controller/src/ComposableController.ts
+++ b/packages/composable-controller/src/ComposableController.ts
@@ -10,22 +10,24 @@ import { isValidJson, type Json } from '@metamask/utils';
 export const controllerName = 'ComposableController';
 
 /*
- * This type encompasses controllers based on either BaseControllerV1 or
+ * The following three types encompass controllers based on either BaseControllerV1 or
  * BaseController. The BaseController type can't be included directly
  * because the generic parameters it expects require knowing the exact state
  * shape, so instead we look for an object with the BaseController properties
  * that we use in the ComposableController (name and state).
  */
+// As explained above, `any` is used to include all `BaseControllerV1` instances.
+// TODO: Remove this type once `BaseControllerV2` migrations are completed for all controllers.
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+type BaseControllerV1Instance = BaseControllerV1<any, any>;
+
+type BaseControllerV2Instance = { name: string; state: Record<string, Json> };
+
 type ControllerInstance =
   // As explained above, `any` is used to include all `BaseControllerV1` instances.
-  // TODO: Remove first union member once `BaseControllerV2` migrations are completed for all controllers.
+  // TODO: Remove `BaseControllerV1Instance` once `BaseControllerV2` migrations are completed for all controllers.
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  BaseControllerV1<any, any> | { name: string; state: Record<string, Json> };
-
-/**
- * List of child controller instances
- */
-export type ControllerList = ControllerInstance[];
+  BaseControllerV1Instance | BaseControllerV2Instance;
 
 /**
  * Determines if the given controller is an instance of BaseControllerV1
@@ -119,7 +121,7 @@ export class ComposableController extends BaseController<
     controllers,
     messenger,
   }: {
-    controllers: ControllerList;
+    controllers: ControllerInstance[];
     messenger: ComposableControllerMessenger;
   }) {
     if (messenger === undefined) {
diff --git a/packages/composable-controller/src/index.ts b/packages/composable-controller/src/index.ts
index 5fc5a803c5d..9deb15385bb 100644
--- a/packages/composable-controller/src/index.ts
+++ b/packages/composable-controller/src/index.ts
@@ -1,5 +1,4 @@
 export type {
-  ControllerList,
   ComposableControllerState,
   ComposableControllerStateChangeEvent,
   ComposableControllerEvents,

From 68f2a04ef85654a1bad510286c2b64b8614dd0d8 Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 21 Feb 2024 08:53:34 -0500
Subject: [PATCH 19/25] Populate metadata object in constructor with child
 controllers

---
 .../composable-controller/src/ComposableController.ts | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/packages/composable-controller/src/ComposableController.ts b/packages/composable-controller/src/ComposableController.ts
index 456539f7da4..ba12539ace4 100644
--- a/packages/composable-controller/src/ComposableController.ts
+++ b/packages/composable-controller/src/ComposableController.ts
@@ -4,6 +4,7 @@ import type {
   RestrictedControllerMessenger,
   BaseState,
   BaseConfig,
+  StateMetadata,
 } from '@metamask/base-controller';
 import { isValidJson, type Json } from '@metamask/utils';
 
@@ -130,7 +131,15 @@ export class ComposableController extends BaseController<
 
     super({
       name: controllerName,
-      metadata: {},
+      metadata: controllers.reduce<StateMetadata<ComposableControllerState>>(
+        (metadata, controller) => ({
+          ...metadata,
+          [controller.name]: isBaseController(controller)
+            ? controller.metadata
+            : { persist: true, anonymous: true },
+        }),
+        {},
+      ),
       state: controllers.reduce<ComposableControllerState>(
         (state, controller) => {
           return { ...state, [controller.name]: controller.state };

From 523f74615912021ad9afbddb427b98beb9f115c2 Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 21 Feb 2024 09:26:00 -0500
Subject: [PATCH 20/25] Fix jsdoc

---
 packages/composable-controller/src/ComposableController.ts | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/packages/composable-controller/src/ComposableController.ts b/packages/composable-controller/src/ComposableController.ts
index ba12539ace4..ff208a99aa1 100644
--- a/packages/composable-controller/src/ComposableController.ts
+++ b/packages/composable-controller/src/ComposableController.ts
@@ -155,8 +155,7 @@ export class ComposableController extends BaseController<
   }
 
   /**
-   * Constructor helper that adds a child controller instance to composable controller state
-   * and subscribes to child controller state changes.
+   * Constructor helper that subscribes to child controller state changes.
    * @param controller - Controller instance to update
    * TODO: Remove `isBaseControllerV1` branch once `BaseControllerV2` migrations are completed for all controllers.
    */

From 3b687f42f0d24cc519dd499fb492d2e1f29c3948 Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 21 Feb 2024 14:47:20 -0500
Subject: [PATCH 21/25] Add jsdoc for types `BaseControllerV{1,2}Instance`,
 `ControllerInstance`

---
 .../src/ComposableController.ts               | 40 +++++++++++--------
 1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/packages/composable-controller/src/ComposableController.ts b/packages/composable-controller/src/ComposableController.ts
index ff208a99aa1..6cecf0b5072 100644
--- a/packages/composable-controller/src/ComposableController.ts
+++ b/packages/composable-controller/src/ComposableController.ts
@@ -10,25 +10,33 @@ import { isValidJson, type Json } from '@metamask/utils';
 
 export const controllerName = 'ComposableController';
 
-/*
- * The following three types encompass controllers based on either BaseControllerV1 or
- * BaseController. The BaseController type can't be included directly
- * because the generic parameters it expects require knowing the exact state
- * shape, so instead we look for an object with the BaseController properties
- * that we use in the ComposableController (name and state).
- */
-// As explained above, `any` is used to include all `BaseControllerV1` instances.
 // TODO: Remove this type once `BaseControllerV2` migrations are completed for all controllers.
-// eslint-disable-next-line @typescript-eslint/no-explicit-any
-type BaseControllerV1Instance = BaseControllerV1<any, any>;
+/**
+ * A type encompassing all controller instances that extend from `BaseControllerV1`.
+ */
+type BaseControllerV1Instance =
+  // `any` is used to include all `BaseControllerV1` instances.
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  BaseControllerV1<any, any>;
 
-type BaseControllerV2Instance = { name: string; state: Record<string, Json> };
+/**
+ * A type encompassing all controller instances that extend from `BaseController` (formerly `BaseControllerV2`).
+ *
+ * The `BaseController` class itself can't be used directly as a type representing all of its subclasses,
+ * because the generic parameters it expects require knowing the exact shape of the controller's state and messenger.
+ *
+ * Instead, we look for an object with the `BaseController` properties that we use in the ComposableController (name and state).
+ */
+type BaseControllerV2Instance = {
+  name: string;
+  state: Record<string, Json>;
+};
 
-type ControllerInstance =
-  // As explained above, `any` is used to include all `BaseControllerV1` instances.
-  // TODO: Remove `BaseControllerV1Instance` once `BaseControllerV2` migrations are completed for all controllers.
-  // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  BaseControllerV1Instance | BaseControllerV2Instance;
+// TODO: Remove `BaseControllerV1Instance` member once `BaseControllerV2` migrations are completed for all controllers.
+/**
+ * A type encompassing all controller instances that extend from `BaseControllerV1` or `BaseController`.
+ */
+type ControllerInstance = BaseControllerV1Instance | BaseControllerV2Instance;
 
 /**
  * Determines if the given controller is an instance of BaseControllerV1

From c5edafd7ea19679070a746435e2b5e5243709486 Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 21 Feb 2024 14:47:47 -0500
Subject: [PATCH 22/25] Export types `ControllerInstance`,
 `BaseControllerV{1,2}Instance`

---
 packages/composable-controller/CHANGELOG.md               | 3 ++-
 .../composable-controller/src/ComposableController.ts     | 8 +++++---
 packages/composable-controller/src/index.ts               | 3 +++
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/packages/composable-controller/CHANGELOG.md b/packages/composable-controller/CHANGELOG.md
index 401ebee7b27..09c143b4211 100644
--- a/packages/composable-controller/CHANGELOG.md
+++ b/packages/composable-controller/CHANGELOG.md
@@ -9,7 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
-- Add exports `isBaseControllerV1` and `isBaseController`, which are type guards for validating controller instances ([#3904](https://github.com/MetaMask/core/pull/3904))
+- Add and export functions `isBaseControllerV1` and `isBaseController`, which are type guards for validating controller instances ([#3904](https://github.com/MetaMask/core/pull/3904))
+- Add and export types `BaseControllerV1Instance`, `BaseControllerV2Instance`, `ControllerInstance` which are the narrowest supertypes for all controllers extending from, respectively, `BaseControllerV1`, `BaseController`, and both ([#3904](https://github.com/MetaMask/core/pull/3904))
 
 ### Changed
 
diff --git a/packages/composable-controller/src/ComposableController.ts b/packages/composable-controller/src/ComposableController.ts
index 6cecf0b5072..fc3fd2565be 100644
--- a/packages/composable-controller/src/ComposableController.ts
+++ b/packages/composable-controller/src/ComposableController.ts
@@ -14,7 +14,7 @@ export const controllerName = 'ComposableController';
 /**
  * A type encompassing all controller instances that extend from `BaseControllerV1`.
  */
-type BaseControllerV1Instance =
+export type BaseControllerV1Instance =
   // `any` is used to include all `BaseControllerV1` instances.
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   BaseControllerV1<any, any>;
@@ -27,7 +27,7 @@ type BaseControllerV1Instance =
  *
  * Instead, we look for an object with the `BaseController` properties that we use in the ComposableController (name and state).
  */
-type BaseControllerV2Instance = {
+export type BaseControllerV2Instance = {
   name: string;
   state: Record<string, Json>;
 };
@@ -36,7 +36,9 @@ type BaseControllerV2Instance = {
 /**
  * A type encompassing all controller instances that extend from `BaseControllerV1` or `BaseController`.
  */
-type ControllerInstance = BaseControllerV1Instance | BaseControllerV2Instance;
+export type ControllerInstance =
+  | BaseControllerV1Instance
+  | BaseControllerV2Instance;
 
 /**
  * Determines if the given controller is an instance of BaseControllerV1
diff --git a/packages/composable-controller/src/index.ts b/packages/composable-controller/src/index.ts
index 9deb15385bb..c803f27d442 100644
--- a/packages/composable-controller/src/index.ts
+++ b/packages/composable-controller/src/index.ts
@@ -1,4 +1,7 @@
 export type {
+  BaseControllerV1Instance,
+  BaseControllerV2Instance,
+  ControllerInstance,
   ComposableControllerState,
   ComposableControllerStateChangeEvent,
   ComposableControllerEvents,

From 9e7a6255738acece3912bc29f002cd6107a8273f Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 21 Feb 2024 11:50:07 -0800
Subject: [PATCH 23/25] Update packages/composable-controller/CHANGELOG.md

Co-authored-by: Elliot Winkler <elliot.winkler@gmail.com>
---
 packages/composable-controller/CHANGELOG.md | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/packages/composable-controller/CHANGELOG.md b/packages/composable-controller/CHANGELOG.md
index 09c143b4211..da123f4ceb4 100644
--- a/packages/composable-controller/CHANGELOG.md
+++ b/packages/composable-controller/CHANGELOG.md
@@ -14,12 +14,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
-- **BREAKING:** Add `@metamask/utils` ^8.3.0 as a dependency. ([#3904](https://github.com/MetaMask/core/pull/3904))
-- Throws an error if a non-controller is passed into the `controllers` constructor option ([#3904](https://github.com/MetaMask/core/pull/3904))
+- **BREAKING:** Passing a non-controller into `controllers` constructor option now throws an error ([#3904](https://github.com/MetaMask/core/pull/3904))
+- **BREAKING:** The `AllowedActions` parameter of the `ComposableControllerMessenger` type is narrowed from `string` to `never`, as `ComposableController` does not use any external controller actions. ([#3904](https://github.com/MetaMask/core/pull/3904))
+- Add `@metamask/utils` ^8.3.0 as a dependency. ([#3904](https://github.com/MetaMask/core/pull/3904))
 
 ### Removed
-
-- **BREAKING:** The `AllowedActions` parameter of the `ComposableControllerMessenger` type is narrowed from `string` to `never`, as `ComposableController` does not use any external controller actions. ([#3904](https://github.com/MetaMask/core/pull/3904))
 - **BREAKING:** Remove `ControllerList` as an exported type. ([#3904](https://github.com/MetaMask/core/pull/3904))
 
 ## [5.0.1]

From 8c5accecb2c7e2137aae6a014e9b33cd377a8b19 Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 21 Feb 2024 11:50:47 -0800
Subject: [PATCH 24/25] Update import statement for non-dependency to use
 `@metamask/` prefix

Co-authored-by: Elliot Winkler <elliot.winkler@gmail.com>
---
 packages/composable-controller/src/ComposableController.test.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/composable-controller/src/ComposableController.test.ts b/packages/composable-controller/src/ComposableController.test.ts
index 6087de8313e..303e956951b 100644
--- a/packages/composable-controller/src/ComposableController.test.ts
+++ b/packages/composable-controller/src/ComposableController.test.ts
@@ -10,7 +10,7 @@ import {
 import type { Patch } from 'immer';
 import * as sinon from 'sinon';
 
-import { JsonRpcEngine } from '../../json-rpc-engine/src/JsonRpcEngine';
+import { JsonRpcEngine } from '@metamask/json-rpc-engine';
 import type { ComposableControllerEvents } from './ComposableController';
 import { ComposableController } from './ComposableController';
 

From 856001b32713f59e71529a45cc31cab1d3d05592 Mon Sep 17 00:00:00 2001
From: Jongsun Suh <jongsun.suh@icloud.com>
Date: Wed, 21 Feb 2024 15:01:01 -0500
Subject: [PATCH 25/25] Linter fixes

Linter fix
---
 packages/composable-controller/CHANGELOG.md                     | 1 +
 packages/composable-controller/src/ComposableController.test.ts | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/packages/composable-controller/CHANGELOG.md b/packages/composable-controller/CHANGELOG.md
index da123f4ceb4..32709313aef 100644
--- a/packages/composable-controller/CHANGELOG.md
+++ b/packages/composable-controller/CHANGELOG.md
@@ -19,6 +19,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add `@metamask/utils` ^8.3.0 as a dependency. ([#3904](https://github.com/MetaMask/core/pull/3904))
 
 ### Removed
+
 - **BREAKING:** Remove `ControllerList` as an exported type. ([#3904](https://github.com/MetaMask/core/pull/3904))
 
 ## [5.0.1]
diff --git a/packages/composable-controller/src/ComposableController.test.ts b/packages/composable-controller/src/ComposableController.test.ts
index 303e956951b..868605deb1e 100644
--- a/packages/composable-controller/src/ComposableController.test.ts
+++ b/packages/composable-controller/src/ComposableController.test.ts
@@ -7,10 +7,10 @@ import {
   BaseControllerV1,
   ControllerMessenger,
 } from '@metamask/base-controller';
+import { JsonRpcEngine } from '@metamask/json-rpc-engine';
 import type { Patch } from 'immer';
 import * as sinon from 'sinon';
 
-import { JsonRpcEngine } from '@metamask/json-rpc-engine';
 import type { ComposableControllerEvents } from './ComposableController';
 import { ComposableController } from './ComposableController';