initiate shield subscriptions polling (#6770)

## Explanation

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Implemented Polling mechanism for SubscriptionController.
This PR includes the following changes
- **BREAKING**: The `SubscriptionController` now extends
`StaticIntervalPollingController`, and the new polling API
`startPolling` must be used to initiate polling (`startPolling`,
`stopPollingByPollingToken`).
([#6770](#6770))
- **BREAKING**: The `SubscriptionController` now accepts an optional
`pollingInterval` property in the constructor argument, to enable the
configurable polling interval.
([#6770](#6770))
- Prevent unnecessary state updates to avoid emitting `:stateChange` in
`getSubscriptions` method.
([#6770](#6770))

## References

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## Checklist

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


<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Adds polling to `SubscriptionController` with configurable interval
and `getSubscriptionByProduct`, while optimizing state updates;
BREAKING: controller now extends polling controller and requires
`startPolling`.
> 
> - **SubscriptionController**
> - **BREAKING**: Extends `StaticIntervalPollingController`; use
`startPolling`/`stopPollingByPollingToken` to manage polling.
> - Adds optional `pollingInterval` (defaults to
`DEFAULT_POLLING_INTERVAL`).
> - Implements `_executePoll` to fetch subscriptions and trigger
`triggerAccessTokenRefresh` on state changes.
> - Adds `getSubscriptionByProduct(product)` and corresponding action
export.
> - Optimizes `getSubscriptions` to avoid unnecessary state updates via
equality checks (subscriptions, trialed products, customerId).
> - **Dependencies/Config**
> - Adds `@metamask/polling-controller`; updates TS project references.
> - Test updates incl. polling behavior and order-insensitive state
checks; adds `sinon` for fake timers.
> - **Docs**
>   - Changelog updated with new method and breaking changes.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
eee1d7a. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: lwin-kyaw

packages/subscription-controller/CHANGELOG.md

@@ -7,6 +7,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Added new public method, `getSubscriptionByProduct` which accepts `product` name as parameter and return the relevant subscription. ([#6770](https://github.com/MetaMask/core/pull/6770))
+
+### Changed
+
+- **BREAKING**: The `SubscriptionController` now extends `StaticIntervalPollingController`, and the new polling API `startPolling` must be used to initiate polling (`startPolling`, `stopPollingByPollingToken`). ([#6770](https://github.com/MetaMask/core/pull/6770))
+- **BREAKING**: The `SubscriptionController` now accepts an optional `pollingInterval` property in the constructor argument, to enable the configurable polling interval. ([#6770](https://github.com/MetaMask/core/pull/6770))
+- Prevent unnecessary state updates to avoid emitting `:stateChange` in `getSubscriptions` method. ([#6770](https://github.com/MetaMask/core/pull/6770))
+
 ## [0.5.0]
 
 ### Changed

packages/subscription-controller/package.json

@@ -49,6 +49,7 @@
   "dependencies": {
     "@metamask/base-controller": "^8.4.0",
     "@metamask/controller-utils": "^11.14.0",
+    "@metamask/polling-controller": "^14.0.0",
     "@metamask/utils": "^11.8.1"
   },
   "devDependencies": {
@@ -57,6 +58,7 @@
     "@types/jest": "^27.4.1",
     "deepmerge": "^4.2.2",
     "jest": "^27.5.1",
+    "sinon": "^9.2.4",
     "ts-jest": "^27.1.4",
     "typedoc": "^0.24.8",
     "typedoc-plugin-missing-exports": "^2.0.0",

packages/subscription-controller/src/SubscriptionController.test.ts

@@ -1,4 +1,5 @@
 import { deriveStateFromMetadata, Messenger } from '@metamask/base-controller';
+import * as sinon from 'sinon';
 
 import {
   controllerName,
@@ -22,13 +23,15 @@ import type {
   StartCryptoSubscriptionRequest,
   StartCryptoSubscriptionResponse,
   UpdatePaymentMethodOpts,
+  Product,
 } from './types';
 import {
   PAYMENT_TYPES,
   PRODUCT_TYPES,
   RECURRING_INTERVALS,
   SUBSCRIPTION_STATUSES,
 } from './types';
+import { advanceTime } from '../../../tests/helpers';
 
 // Mock data
 const MOCK_SUBSCRIPTION: Subscription = {
@@ -269,6 +272,7 @@ describe('SubscriptionController', () => {
         messenger,
         state: initialState,
         subscriptionService: mockService,
+        pollingInterval: 10_000,
       });
 
       expect(controller).toBeDefined();
@@ -291,7 +295,7 @@ describe('SubscriptionController', () => {
     });
   });
 
-  describe('getSubscription', () => {
+  describe('getSubscriptions', () => {
     it('should fetch and store subscription successfully', async () => {
       await withController(async ({ controller, mockService }) => {
         mockService.getSubscriptions.mockResolvedValue(
@@ -371,6 +375,156 @@ describe('SubscriptionController', () => {
         },
       );
     });
+
+    it('should not update state when multiple subscriptions are the same but in different order', async () => {
+      const mockSubscription1 = { ...MOCK_SUBSCRIPTION, id: 'sub_1' };
+      const mockSubscription2 = { ...MOCK_SUBSCRIPTION, id: 'sub_2' };
+      const mockSubscription3 = { ...MOCK_SUBSCRIPTION, id: 'sub_3' };
+
+      await withController(
+        {
+          state: {
+            customerId: 'cus_1',
+            subscriptions: [
+              mockSubscription1,
+              mockSubscription2,
+              mockSubscription3,
+            ],
+          },
+        },
+        async ({ controller, mockService }) => {
+          // Return the same subscriptions but in different order
+          mockService.getSubscriptions.mockResolvedValue({
+            customerId: 'cus_1',
+            subscriptions: [
+              mockSubscription3,
+              mockSubscription1,
+              mockSubscription2,
+            ], // Different order
+            trialedProducts: [],
+          });
+
+          const initialState = [...controller.state.subscriptions];
+          await controller.getSubscriptions();
+
+          // Should not update state since subscriptions are the same (just different order)
+          expect(controller.state.subscriptions).toStrictEqual(initialState);
+        },
+      );
+    });
+
+    it('should not update state when subscriptions are the same but the products are in different order', async () => {
+      const mockProduct1: Product = {
+        // @ts-expect-error - mock data
+        name: 'Product 1',
+        currency: 'usd',
+        unitAmount: 900,
+        unitDecimals: 2,
+      };
+      const mockProduct2: Product = {
+        // @ts-expect-error - mock data
+        name: 'Product 2',
+        currency: 'usd',
+        unitAmount: 900,
+        unitDecimals: 2,
+      };
+      const mockSubscription = {
+        ...MOCK_SUBSCRIPTION,
+        products: [mockProduct1, mockProduct2],
+      };
+
+      await withController(
+        {
+          state: {
+            subscriptions: [mockSubscription],
+            trialedProducts: [PRODUCT_TYPES.SHIELD],
+          },
+        },
+        async ({ controller, mockService }) => {
+          mockService.getSubscriptions.mockResolvedValue({
+            ...MOCK_SUBSCRIPTION,
+            subscriptions: [
+              { ...MOCK_SUBSCRIPTION, products: [mockProduct2, mockProduct1] },
+            ],
+            trialedProducts: [PRODUCT_TYPES.SHIELD],
+          });
+          await controller.getSubscriptions();
+          expect(controller.state.subscriptions).toStrictEqual([
+            mockSubscription,
+          ]);
+        },
+      );
+    });
+
+    it('should update state when subscriptions are the same but the trialed products are different', async () => {
+      const mockProduct1: Product = {
+        // @ts-expect-error - mock data
+        name: 'Product 1',
+        currency: 'usd',
+        unitAmount: 900,
+        unitDecimals: 2,
+      };
+      const mockProduct2: Product = {
+        // @ts-expect-error - mock data
+        name: 'Product 2',
+        currency: 'usd',
+        unitAmount: 900,
+        unitDecimals: 2,
+      };
+      const mockSubscription = {
+        ...MOCK_SUBSCRIPTION,
+        products: [mockProduct1, mockProduct2],
+      };
+
+      await withController(
+        {
+          state: {
+            subscriptions: [mockSubscription],
+          },
+        },
+        async ({ controller, mockService }) => {
+          mockService.getSubscriptions.mockResolvedValue({
+            ...MOCK_SUBSCRIPTION,
+            subscriptions: [
+              { ...MOCK_SUBSCRIPTION, products: [mockProduct1, mockProduct2] },
+            ],
+            trialedProducts: [PRODUCT_TYPES.SHIELD],
+          });
+          await controller.getSubscriptions();
+          expect(controller.state.subscriptions).toStrictEqual([
+            mockSubscription,
+          ]);
+          expect(controller.state.trialedProducts).toStrictEqual([
+            PRODUCT_TYPES.SHIELD,
+          ]);
+        },
+      );
+    });
+  });
+
+  describe('getSubscriptionByProduct', () => {
+    it('should get subscription by product successfully', async () => {
+      await withController(
+        {
+          state: {
+            subscriptions: [MOCK_SUBSCRIPTION],
+          },
+        },
+        async ({ controller }) => {
+          expect(
+            controller.getSubscriptionByProduct(PRODUCT_TYPES.SHIELD),
+          ).toStrictEqual(MOCK_SUBSCRIPTION);
+        },
+      );
+    });
+
+    it('should return undefined if no subscription is found', async () => {
+      await withController(async ({ controller }) => {
+        expect(
+          controller.getSubscriptionByProduct(PRODUCT_TYPES.SHIELD),
+        ).toBeUndefined();
+      });
+    });
   });
 
   describe('cancelSubscription', () => {
@@ -699,6 +853,42 @@ describe('SubscriptionController', () => {
     });
   });
 
+  describe('startPolling', () => {
+    let clock: sinon.SinonFakeTimers;
+    beforeEach(() => {
+      // eslint-disable-next-line import-x/namespace
+      clock = sinon.useFakeTimers();
+    });
+
+    afterEach(() => {
+      clock.restore();
+    });
+
+    it('should call getSubscriptions with the correct interval', async () => {
+      await withController(async ({ controller }) => {
+        const getSubscriptionsSpy = jest.spyOn(controller, 'getSubscriptions');
+        controller.startPolling({});
+        await advanceTime({ clock, duration: 0 });
+        expect(getSubscriptionsSpy).toHaveBeenCalledTimes(1);
+      });
+    });
+
+    it('should call `triggerAccessTokenRefresh` when the state changes', async () => {
+      await withController(async ({ controller, mockService }) => {
+        mockService.getSubscriptions.mockResolvedValue(
+          MOCK_GET_SUBSCRIPTIONS_RESPONSE,
+        );
+        const triggerAccessTokenRefreshSpy = jest.spyOn(
+          controller,
+          'triggerAccessTokenRefresh',
+        );
+        controller.startPolling({});
+        await advanceTime({ clock, duration: 0 });
+        expect(triggerAccessTokenRefreshSpy).toHaveBeenCalledTimes(1);
+      });
+    });
+  });
+
   describe('integration scenarios', () => {
     it('should handle complete subscription lifecycle with updated logic', async () => {
       await withController(async ({ controller, mockService }) => {