From 0ee2a9dd3cbc0baed8e6ea640beca20863e1cfb6 Mon Sep 17 00:00:00 2001
From: Maarten Zuidhoorn <maarten@zuidhoorn.com>
Date: Fri, 2 May 2025 14:03:41 +0200
Subject: [PATCH 1/2] Remove web worker executor and environment

---
 packages/snaps-controllers/coverage.json      |   8 +-
 .../src/services/browser.test.ts              |   1 -
 .../snaps-controllers/src/services/browser.ts |   1 -
 .../snaps-controllers/src/services/index.ts   |   1 -
 .../WebWorkerExecutionService.test.browser.ts | 226 ------------------
 .../webworker/WebWorkerExecutionService.ts    | 122 ----------
 .../src/services/webworker/index.ts           |   1 -
 packages/snaps-controllers/vitest.config.mts  |  20 --
 .../coverage.json                             |   8 +-
 .../snaps-execution-environments/package.json |   1 -
 .../WebWorkerSnapExecutor.test.browser.ts     | 172 -------------
 .../executor/WebWorkerSnapExecutor.ts         |  37 ---
 .../src/webworker/executor/index.ts           |   9 -
 .../pool/WebWorkerPool.test.browser.ts        | 188 ---------------
 .../src/webworker/pool/WebWorkerPool.ts       | 211 ----------------
 .../src/webworker/pool/index.ts               |   9 -
 .../webpack.config.js                         |  18 --
 yarn.lock                                     |  25 +-
 18 files changed, 31 insertions(+), 1027 deletions(-)
 delete mode 100644 packages/snaps-controllers/src/services/webworker/WebWorkerExecutionService.test.browser.ts
 delete mode 100644 packages/snaps-controllers/src/services/webworker/WebWorkerExecutionService.ts
 delete mode 100644 packages/snaps-controllers/src/services/webworker/index.ts
 delete mode 100644 packages/snaps-execution-environments/src/webworker/executor/WebWorkerSnapExecutor.test.browser.ts
 delete mode 100644 packages/snaps-execution-environments/src/webworker/executor/WebWorkerSnapExecutor.ts
 delete mode 100644 packages/snaps-execution-environments/src/webworker/executor/index.ts
 delete mode 100644 packages/snaps-execution-environments/src/webworker/pool/WebWorkerPool.test.browser.ts
 delete mode 100644 packages/snaps-execution-environments/src/webworker/pool/WebWorkerPool.ts
 delete mode 100644 packages/snaps-execution-environments/src/webworker/pool/index.ts

diff --git a/packages/snaps-controllers/coverage.json b/packages/snaps-controllers/coverage.json
index 3e58e6d076..f7f509342b 100644
--- a/packages/snaps-controllers/coverage.json
+++ b/packages/snaps-controllers/coverage.json
@@ -1,6 +1,6 @@
 {
-  "branches": 93.54,
-  "functions": 97.38,
-  "lines": 98.34,
-  "statements": 98.08
+  "branches": 93.51,
+  "functions": 97.36,
+  "lines": 98.33,
+  "statements": 98.17
 }
diff --git a/packages/snaps-controllers/src/services/browser.test.ts b/packages/snaps-controllers/src/services/browser.test.ts
index 3a42acb126..b4cf203e56 100644
--- a/packages/snaps-controllers/src/services/browser.test.ts
+++ b/packages/snaps-controllers/src/services/browser.test.ts
@@ -6,7 +6,6 @@ describe('browser entrypoint', () => {
     'setupMultiplex',
     'IframeExecutionService',
     'OffscreenExecutionService',
-    'WebWorkerExecutionService',
     'ProxyPostMessageStream',
     'WebViewExecutionService',
     'WebViewMessageStream',
diff --git a/packages/snaps-controllers/src/services/browser.ts b/packages/snaps-controllers/src/services/browser.ts
index 1b80e9e865..871061032c 100644
--- a/packages/snaps-controllers/src/services/browser.ts
+++ b/packages/snaps-controllers/src/services/browser.ts
@@ -5,4 +5,3 @@ export * from './ProxyPostMessageStream';
 export * from './iframe';
 export * from './offscreen';
 export * from './webview';
-export { WebWorkerExecutionService } from './webworker';
diff --git a/packages/snaps-controllers/src/services/index.ts b/packages/snaps-controllers/src/services/index.ts
index b72ca852ee..2e0ea1263b 100644
--- a/packages/snaps-controllers/src/services/index.ts
+++ b/packages/snaps-controllers/src/services/index.ts
@@ -3,4 +3,3 @@ export type * from './ExecutionService';
 export * from './ProxyPostMessageStream';
 export * from './iframe';
 export * from './offscreen';
-export { WebWorkerExecutionService } from './webworker';
diff --git a/packages/snaps-controllers/src/services/webworker/WebWorkerExecutionService.test.browser.ts b/packages/snaps-controllers/src/services/webworker/WebWorkerExecutionService.test.browser.ts
deleted file mode 100644
index 463bc275ee..0000000000
--- a/packages/snaps-controllers/src/services/webworker/WebWorkerExecutionService.test.browser.ts
+++ /dev/null
@@ -1,226 +0,0 @@
-import { HandlerType } from '@metamask/snaps-utils';
-import {
-  DEFAULT_SNAP_BUNDLE,
-  MOCK_LOCAL_SNAP_ID,
-  MOCK_ORIGIN,
-  MOCK_SNAP_ID,
-  spy,
-} from '@metamask/snaps-utils/test-utils';
-import { describe, it, expect, afterEach } from 'vitest';
-
-import {
-  WebWorkerExecutionService,
-  WORKER_POOL_ID,
-} from './WebWorkerExecutionService';
-import { MOCK_BLOCK_NUMBER } from '../../test-utils/constants';
-import { createService } from '../../test-utils/service';
-
-const WORKER_POOL_URL = 'http://localhost:63315/worker/pool/index.html';
-
-describe('WebWorkerExecutionService', () => {
-  afterEach(() => {
-    document.getElementById(WORKER_POOL_ID)?.remove();
-  });
-
-  it('can boot', async () => {
-    const { service } = createService(WebWorkerExecutionService, {
-      documentUrl: new URL(WORKER_POOL_URL),
-    });
-
-    expect(service).toBeDefined();
-    await service.terminateAllSnaps();
-  });
-
-  it('only creates a single iframe', async () => {
-    const { service } = createService(WebWorkerExecutionService, {
-      documentUrl: new URL(WORKER_POOL_URL),
-    });
-
-    await service.executeSnap({
-      snapId: MOCK_SNAP_ID,
-      sourceCode: `
-        module.exports.onRpcRequest = () => null;
-      `,
-      endowments: [],
-    });
-
-    await service.executeSnap({
-      snapId: MOCK_LOCAL_SNAP_ID,
-      sourceCode: `
-        module.exports.onRpcRequest = () => null;
-      `,
-      endowments: [],
-    });
-
-    expect(document.getElementById(WORKER_POOL_ID)).not.toBeNull();
-    expect(document.getElementsByTagName('iframe')).toHaveLength(1);
-
-    await service.terminateAllSnaps();
-  });
-
-  it('can create a snap worker and start the snap', async () => {
-    const { service } = createService(WebWorkerExecutionService, {
-      documentUrl: new URL(WORKER_POOL_URL),
-    });
-
-    const response = await service.executeSnap({
-      snapId: 'TestSnap',
-      sourceCode: `
-        module.exports.onRpcRequest = () => null;
-      `,
-      endowments: [],
-    });
-
-    expect(response).toBe('OK');
-    await service.terminateAllSnaps();
-  });
-
-  it('executes a snap', async () => {
-    const { service } = createService(WebWorkerExecutionService, {
-      documentUrl: new URL(WORKER_POOL_URL),
-    });
-
-    await service.executeSnap({
-      snapId: MOCK_SNAP_ID,
-      sourceCode: DEFAULT_SNAP_BUNDLE,
-      endowments: ['console'],
-    });
-
-    const result = await service.handleRpcRequest(MOCK_SNAP_ID, {
-      origin: MOCK_ORIGIN,
-      handler: HandlerType.OnRpcRequest,
-      request: {
-        jsonrpc: '2.0',
-        id: 1,
-        method: 'foo',
-      },
-    });
-
-    expect(result).toBe('foo1');
-
-    await service.terminateAllSnaps();
-  });
-
-  it('can handle a crashed snap', async () => {
-    expect.assertions(1);
-    const { service } = createService(WebWorkerExecutionService, {
-      documentUrl: new URL(WORKER_POOL_URL),
-    });
-
-    const action = async () => {
-      await service.executeSnap({
-        snapId: MOCK_SNAP_ID,
-        sourceCode: `
-          throw new Error("Crashed.");
-        `,
-        endowments: [],
-      });
-    };
-
-    await expect(action()).rejects.toThrow(
-      `Error while running snap '${MOCK_SNAP_ID}': Crashed.`,
-    );
-    await service.terminateAllSnaps();
-  });
-
-  it('can detect outbound requests', async () => {
-    expect.assertions(5);
-
-    const { service, messenger } = createService(WebWorkerExecutionService, {
-      documentUrl: new URL(WORKER_POOL_URL),
-    });
-
-    const publishSpy = spy(messenger, 'publish');
-
-    const executeResult = await service.executeSnap({
-      snapId: MOCK_SNAP_ID,
-      sourceCode: `
-        module.exports.onRpcRequest = () => ethereum.request({ method: 'eth_blockNumber', params: [] });
-      `,
-      endowments: ['ethereum'],
-    });
-
-    expect(executeResult).toBe('OK');
-
-    const result = await service.handleRpcRequest(MOCK_SNAP_ID, {
-      origin: 'foo',
-      handler: HandlerType.OnRpcRequest,
-      request: {
-        jsonrpc: '2.0',
-        id: 1,
-        method: 'foobar',
-        params: [],
-      },
-    });
-
-    expect(result).toBe(MOCK_BLOCK_NUMBER);
-
-    expect(publishSpy.calls).toHaveLength(2);
-    expect(publishSpy.calls[0]).toStrictEqual({
-      args: ['ExecutionService:outboundRequest', MOCK_SNAP_ID],
-      result: undefined,
-    });
-
-    expect(publishSpy.calls[1]).toStrictEqual({
-      args: ['ExecutionService:outboundResponse', MOCK_SNAP_ID],
-      result: undefined,
-    });
-
-    await service.terminateAllSnaps();
-    publishSpy.reset();
-  });
-
-  it('confirms that events are secured', async () => {
-    // Check if the security critical properties of the Event object
-    // are unavailable. This will confirm that executeLockdownEvents works
-    // inside snaps-execution-environments
-    const { service } = createService(WebWorkerExecutionService, {
-      documentUrl: new URL(WORKER_POOL_URL),
-    });
-
-    await service.executeSnap({
-      snapId: MOCK_SNAP_ID,
-      sourceCode: `
-        module.exports.onRpcRequest = async ({ request }) => {
-            let result;
-            const promise = new Promise((resolve) => {
-                const xhr = new XMLHttpRequest();
-                xhr.open('GET', 'https://metamask.io/');
-                xhr.send();
-                xhr.onreadystatechange = (ev) => {
-                  result = ev;
-                  resolve();
-                };
-            });
-            await promise;
-
-            return {
-              targetIsUndefined: result.target === undefined,
-              currentTargetIsUndefined: result.target === undefined,
-              srcElementIsUndefined: result.target === undefined,
-              composedPathIsUndefined: result.target === undefined
-            };
-        };
-      `,
-      endowments: ['console', 'XMLHttpRequest'],
-    });
-
-    const result = await service.handleRpcRequest(MOCK_SNAP_ID, {
-      origin: 'foo',
-      handler: HandlerType.OnRpcRequest,
-      request: {
-        jsonrpc: '2.0',
-        id: 1,
-        method: 'foobar',
-        params: [],
-      },
-    });
-
-    expect(result).toStrictEqual({
-      targetIsUndefined: true,
-      currentTargetIsUndefined: true,
-      srcElementIsUndefined: true,
-      composedPathIsUndefined: true,
-    });
-  });
-});
diff --git a/packages/snaps-controllers/src/services/webworker/WebWorkerExecutionService.ts b/packages/snaps-controllers/src/services/webworker/WebWorkerExecutionService.ts
deleted file mode 100644
index bd586543f2..0000000000
--- a/packages/snaps-controllers/src/services/webworker/WebWorkerExecutionService.ts
+++ /dev/null
@@ -1,122 +0,0 @@
-import type { BasePostMessageStream } from '@metamask/post-message-stream';
-import { WindowPostMessageStream } from '@metamask/post-message-stream';
-import { createWindow } from '@metamask/snaps-utils';
-import { assert } from '@metamask/utils';
-import { nanoid } from 'nanoid';
-
-import type {
-  ExecutionServiceArgs,
-  TerminateJobArgs,
-} from '../AbstractExecutionService';
-import { AbstractExecutionService } from '../AbstractExecutionService';
-import { ProxyPostMessageStream } from '../ProxyPostMessageStream';
-
-type WebWorkerExecutionEnvironmentServiceArgs = {
-  documentUrl: URL;
-} & ExecutionServiceArgs;
-
-export const WORKER_POOL_ID = 'snaps-worker-pool';
-
-export class WebWorkerExecutionService extends AbstractExecutionService<string> {
-  readonly #documentUrl: URL;
-
-  #runtimeStream?: BasePostMessageStream;
-
-  /**
-   * Create a new webworker execution service.
-   *
-   * @param args - The constructor arguments.
-   * @param args.documentUrl - The URL of the worker pool document to use as the
-   * execution environment.
-   * @param args.messenger - The messenger to use for communication with the
-   * `SnapController`.
-   * @param args.setupSnapProvider - The function to use to set up the snap
-   * provider.
-   */
-  constructor({
-    documentUrl,
-    messenger,
-    setupSnapProvider,
-    ...args
-  }: WebWorkerExecutionEnvironmentServiceArgs) {
-    super({
-      ...args,
-      messenger,
-      setupSnapProvider,
-    });
-
-    this.#documentUrl = documentUrl;
-  }
-
-  /**
-   * Send a termination command to the worker pool document.
-   *
-   * @param job - The job to terminate.
-   */
-  // TODO: Either fix this lint violation or explain why it's necessary to
-  //  ignore.
-  // eslint-disable-next-line @typescript-eslint/no-misused-promises
-  protected async terminateJob(job: TerminateJobArgs<string>) {
-    // The `AbstractExecutionService` will have already closed the job stream,
-    // so we write to the runtime stream directly.
-    assert(this.#runtimeStream, 'Runtime stream not initialized.');
-    this.#runtimeStream.write({
-      jobId: job.id,
-      data: {
-        jsonrpc: '2.0',
-        method: 'terminateJob',
-        id: nanoid(),
-      },
-    });
-  }
-
-  /**
-   * Create a new stream for the specified job. This wraps the runtime stream
-   * in a stream specific to the job.
-   *
-   * @param jobId - The job ID.
-   * @returns An object with the worker ID and stream.
-   */
-  protected async initEnvStream(jobId: string) {
-    // Lazily create the worker pool document.
-    await this.createDocument();
-
-    // `createDocument` should have initialized the runtime stream.
-    assert(this.#runtimeStream, 'Runtime stream not initialized.');
-
-    const stream = new ProxyPostMessageStream({
-      stream: this.#runtimeStream,
-      jobId,
-    });
-
-    return { worker: jobId, stream };
-  }
-
-  /**
-   * Creates the worker pool document to be used as the execution environment.
-   *
-   * If the document already exists, this does nothing.
-   */
-  // TODO: Either fix this lint violation or explain why it's necessary to
-  //  ignore.
-  // eslint-disable-next-line no-restricted-syntax
-  private async createDocument() {
-    // We only want to create a single pool.
-    if (document.getElementById(WORKER_POOL_ID)) {
-      return;
-    }
-
-    const window = await createWindow({
-      uri: this.#documentUrl.href,
-      id: WORKER_POOL_ID,
-      sandbox: false,
-    });
-
-    this.#runtimeStream = new WindowPostMessageStream({
-      name: 'parent',
-      target: 'child',
-      targetWindow: window,
-      targetOrigin: '*',
-    });
-  }
-}
diff --git a/packages/snaps-controllers/src/services/webworker/index.ts b/packages/snaps-controllers/src/services/webworker/index.ts
deleted file mode 100644
index 6c1383c319..0000000000
--- a/packages/snaps-controllers/src/services/webworker/index.ts
+++ /dev/null
@@ -1 +0,0 @@
-export * from './WebWorkerExecutionService';
diff --git a/packages/snaps-controllers/vitest.config.mts b/packages/snaps-controllers/vitest.config.mts
index a05377b1dd..3e905cd16e 100644
--- a/packages/snaps-controllers/vitest.config.mts
+++ b/packages/snaps-controllers/vitest.config.mts
@@ -14,16 +14,6 @@ const IFRAME_TEST_PATH = join(
   './src/services/iframe/test',
 );
 
-const WORKER_EXECUTOR_PATH = join(
-  import.meta.dirname,
-  '../snaps-execution-environments/dist/webpack/worker-executor',
-);
-
-const WORKER_POOL_PATH = join(
-  import.meta.dirname,
-  '../snaps-execution-environments/dist/webpack/worker-pool',
-);
-
 export default defineConfig({
   plugins: [tsconfigPaths(), nodePolyfills()],
 
@@ -38,16 +28,6 @@ export default defineConfig({
         target: `http://localhost:63315/@fs${IFRAME_TEST_PATH}`,
         rewrite: (path) => path.replace(/^\/iframe\/test/u, ''),
       },
-
-      '/worker/executor': {
-        target: `http://localhost:63315/@fs${WORKER_EXECUTOR_PATH}`,
-        rewrite: (path) => path.replace(/^\/worker\/executor/u, ''),
-      },
-
-      '/worker/pool': {
-        target: `http://localhost:63315/@fs${WORKER_POOL_PATH}`,
-        rewrite: (path) => path.replace(/^\/worker\/pool/u, ''),
-      },
     },
 
     fs: {
diff --git a/packages/snaps-execution-environments/coverage.json b/packages/snaps-execution-environments/coverage.json
index 31ccde4fe9..1e437e58f6 100644
--- a/packages/snaps-execution-environments/coverage.json
+++ b/packages/snaps-execution-environments/coverage.json
@@ -1,6 +1,6 @@
 {
-  "branches": 90.78,
-  "functions": 94.96,
-  "lines": 90.84,
-  "statements": 90.25
+  "branches": 90,
+  "functions": 94.57,
+  "lines": 90.13,
+  "statements": 89.5
 }
diff --git a/packages/snaps-execution-environments/package.json b/packages/snaps-execution-environments/package.json
index 7f04d57b53..a794af00d6 100644
--- a/packages/snaps-execution-environments/package.json
+++ b/packages/snaps-execution-environments/package.json
@@ -75,7 +75,6 @@
     "@metamask/snaps-utils": "workspace:^",
     "@metamask/superstruct": "^3.2.1",
     "@metamask/utils": "^11.4.0",
-    "nanoid": "^3.3.10",
     "readable-stream": "^3.6.2"
   },
   "devDependencies": {
diff --git a/packages/snaps-execution-environments/src/webworker/executor/WebWorkerSnapExecutor.test.browser.ts b/packages/snaps-execution-environments/src/webworker/executor/WebWorkerSnapExecutor.test.browser.ts
deleted file mode 100644
index cbaf72b7e5..0000000000
--- a/packages/snaps-execution-environments/src/webworker/executor/WebWorkerSnapExecutor.test.browser.ts
+++ /dev/null
@@ -1,172 +0,0 @@
-// eslint-disable-next-line import-x/no-unassigned-import
-import 'ses';
-import { HandlerType } from '@metamask/snaps-utils';
-import type { SpyFunction } from '@metamask/snaps-utils/test-utils';
-import {
-  MOCK_ORIGIN,
-  MOCK_SNAP_ID,
-  MockWindowPostMessageStream,
-  spy,
-} from '@metamask/snaps-utils/test-utils';
-import { describe, expect, it, beforeAll, beforeEach } from 'vitest';
-
-import { WebWorkerSnapExecutor } from './WebWorkerSnapExecutor';
-
-/**
- * Write a message to the stream, wrapped with the job ID.
- *
- * @param stream - The stream to write to.
- * @param message - The message to write.
- */
-function writeMessage(
-  stream: MockWindowPostMessageStream,
-  message: Record<string, unknown>,
-) {
-  stream.write(message);
-}
-
-/**
- * Wait for a response from the stream.
- *
- * @param stream - The stream to wait for a response on.
- * @returns The raw JSON-RPC response object.
- */
-async function getResponse(
-  stream: MockWindowPostMessageStream,
-): Promise<Record<string, unknown>> {
-  return new Promise((resolve) => {
-    stream.once('response', (data) => {
-      resolve(data);
-    });
-  });
-}
-
-describe('WebWorkerSnapExecutor', () => {
-  let consoleSpy: SpyFunction<unknown, unknown>;
-
-  beforeAll(() => {
-    // @ts-expect-error - `globalThis.process` is not optional.
-    delete globalThis.process;
-
-    // SES makes the `console.error` property non-writable, so we have to
-    // create the spy before lockdown.
-    consoleSpy = spy(console, 'error');
-
-    lockdown({
-      domainTaming: 'unsafe',
-      errorTaming: 'unsafe',
-      stackFiltering: 'verbose',
-    });
-  });
-
-  beforeEach(() => {
-    consoleSpy.clear();
-  });
-
-  it('receives and processes commands', async () => {
-    const mockStream = new MockWindowPostMessageStream();
-
-    // Initialize
-    WebWorkerSnapExecutor.initialize(mockStream);
-
-    writeMessage(mockStream, {
-      name: 'command',
-      data: {
-        jsonrpc: '2.0',
-        id: 1,
-        method: 'ping',
-      },
-    });
-
-    expect(await getResponse(mockStream)).toStrictEqual({
-      jsonrpc: '2.0',
-      id: 1,
-      result: 'OK',
-    });
-
-    const CODE = `
-      exports.onRpcRequest = () => {
-        return 'foobar';
-      };
-    `;
-
-    writeMessage(mockStream, {
-      name: 'command',
-      data: {
-        jsonrpc: '2.0',
-        id: 2,
-        method: 'executeSnap',
-        params: [MOCK_SNAP_ID, CODE, []],
-      },
-    });
-
-    expect(await getResponse(mockStream)).toStrictEqual({
-      jsonrpc: '2.0',
-      id: 2,
-      result: 'OK',
-    });
-
-    writeMessage(mockStream, {
-      name: 'command',
-      data: {
-        jsonrpc: '2.0',
-        id: 3,
-        method: 'snapRpc',
-        params: [
-          MOCK_SNAP_ID,
-          HandlerType.OnRpcRequest,
-          MOCK_ORIGIN,
-          { jsonrpc: '2.0', method: '' },
-        ],
-      },
-    });
-
-    expect(await getResponse(mockStream)).toStrictEqual({
-      result: 'foobar',
-      id: 3,
-      jsonrpc: '2.0',
-    });
-  });
-
-  // TODO: Re-enable this test after investigating error handling further.
-
-  it.skip('handles closing the stream', async () => {
-    const mockStream = new MockWindowPostMessageStream();
-
-    // We have to mock close, because otherwise WebDriverIO will break.
-    const closeSpy = spy(globalThis, 'close').mockImplementation(() => {
-      // Do nothing
-    });
-
-    WebWorkerSnapExecutor.initialize(mockStream);
-    mockStream.destroy();
-
-    await new Promise((resolve) => setTimeout(resolve, 1));
-
-    expect(closeSpy.calls).toHaveLength(1);
-
-    closeSpy.reset();
-  });
-
-  // TODO: Re-enable this test after investigating error handling further.
-
-  it.skip('handles stream errors', async () => {
-    const mockStream = new MockWindowPostMessageStream();
-
-    // We have to mock close, because otherwise WebDriverIO will break.
-    const closeSpy = spy(globalThis, 'close').mockImplementation(() => {
-      // Do nothing
-    });
-
-    WebWorkerSnapExecutor.initialize(mockStream);
-    mockStream.emit('error', new Error('test error'));
-
-    expect(closeSpy.calls).toHaveLength(1);
-    expect(consoleSpy.calls).toHaveLength(3);
-    expect(consoleSpy.calls[0].args[0]).toBe(
-      'Parent stream failure, closing worker.',
-    );
-
-    closeSpy.reset();
-  });
-});
diff --git a/packages/snaps-execution-environments/src/webworker/executor/WebWorkerSnapExecutor.ts b/packages/snaps-execution-environments/src/webworker/executor/WebWorkerSnapExecutor.ts
deleted file mode 100644
index 2f13f81d81..0000000000
--- a/packages/snaps-execution-environments/src/webworker/executor/WebWorkerSnapExecutor.ts
+++ /dev/null
@@ -1,37 +0,0 @@
-import ObjectMultiplex from '@metamask/object-multiplex';
-import type { BasePostMessageStream } from '@metamask/post-message-stream';
-import { WebWorkerPostMessageStream } from '@metamask/post-message-stream';
-import { logError, SNAP_STREAM_NAMES } from '@metamask/snaps-utils';
-import { pipeline } from 'readable-stream';
-
-import { BaseSnapExecutor } from '../../common/BaseSnapExecutor';
-import { log } from '../../logging';
-
-export class WebWorkerSnapExecutor extends BaseSnapExecutor {
-  /**
-   * Initialize the WebWorkerSnapExecutor. This creates a post message stream
-   * from and to the parent window, for two-way communication with the iframe.
-   *
-   * @param stream - The stream to use for communication.
-   * @returns An instance of `WebWorkerSnapExecutor`, with the initialized post
-   * message streams.
-   */
-  static initialize(
-    stream: BasePostMessageStream = new WebWorkerPostMessageStream(),
-  ) {
-    log('Worker: Connecting to parent.');
-
-    const mux = new ObjectMultiplex();
-    pipeline(stream, mux, stream, (error) => {
-      if (error) {
-        logError(`Parent stream failure, closing worker.`, error);
-      }
-      self.close();
-    });
-
-    const commandStream = mux.createStream(SNAP_STREAM_NAMES.COMMAND);
-    const rpcStream = mux.createStream(SNAP_STREAM_NAMES.JSON_RPC);
-
-    return new WebWorkerSnapExecutor(commandStream, rpcStream);
-  }
-}
diff --git a/packages/snaps-execution-environments/src/webworker/executor/index.ts b/packages/snaps-execution-environments/src/webworker/executor/index.ts
deleted file mode 100644
index ec8f55ee81..0000000000
--- a/packages/snaps-execution-environments/src/webworker/executor/index.ts
+++ /dev/null
@@ -1,9 +0,0 @@
-import { WebWorkerSnapExecutor } from './WebWorkerSnapExecutor';
-import { executeLockdownEvents } from '../../common/lockdown/lockdown-events';
-import { executeLockdownMore } from '../../common/lockdown/lockdown-more';
-
-// Lockdown is already applied in LavaMoat
-executeLockdownMore();
-executeLockdownEvents();
-
-WebWorkerSnapExecutor.initialize();
diff --git a/packages/snaps-execution-environments/src/webworker/pool/WebWorkerPool.test.browser.ts b/packages/snaps-execution-environments/src/webworker/pool/WebWorkerPool.test.browser.ts
deleted file mode 100644
index c1b62fa350..0000000000
--- a/packages/snaps-execution-environments/src/webworker/pool/WebWorkerPool.test.browser.ts
+++ /dev/null
@@ -1,188 +0,0 @@
-import { MockPostMessageStream, spy } from '@metamask/snaps-utils/test-utils';
-import { assert } from '@metamask/utils';
-import { describe, expect, it } from 'vitest';
-
-import { WebWorkerPool } from './WebWorkerPool';
-
-const MOCK_JOB_ID = 'job-id';
-const WORKER_URL = 'http://localhost:63316/worker/executor/bundle.js';
-
-/**
- * Write a message to the stream, wrapped with the job ID.
- *
- * @param stream - The stream to write to.
- * @param message - The message to write.
- * @param jobId - The job ID.
- */
-function writeMessage(
-  stream: MockPostMessageStream,
-  message: Record<string, unknown>,
-  jobId = MOCK_JOB_ID,
-) {
-  stream.write({
-    jobId,
-    data: message,
-  });
-}
-
-/**
- * Write a termination message to the stream.
- *
- * @param stream - The stream to write to.
- * @returns A promise that resolves after 1 millisecond.
- */
-async function terminateJob(stream: MockPostMessageStream) {
-  writeMessage(stream, {
-    jsonrpc: '2.0',
-    id: 2,
-    method: 'terminateJob',
-  });
-
-  return await new Promise((resolve) => setTimeout(resolve, 1));
-}
-
-/**
- * Wait for a response from the stream.
- *
- * @param stream - The stream to wait for a response on.
- * @returns The raw JSON-RPC response object.
- */
-async function getResponse(
-  stream: MockPostMessageStream,
-): Promise<Record<string, unknown>> {
-  return new Promise((resolve) => {
-    stream.once('response', (data) => {
-      resolve(data);
-    });
-  });
-}
-
-describe('WebWorkerPool', () => {
-  it('forwards messages to the worker', async () => {
-    const mockStream = new MockPostMessageStream();
-
-    WebWorkerPool.initialize(mockStream, WORKER_URL);
-
-    writeMessage(mockStream, {
-      name: 'command',
-      data: {
-        jsonrpc: '2.0',
-        id: 1,
-        method: 'ping',
-      },
-    });
-
-    expect(await getResponse(mockStream)).toEqual({
-      jsonrpc: '2.0',
-      id: 1,
-      result: 'OK',
-    });
-
-    expect(document.getElementById(MOCK_JOB_ID)).toBeDefined();
-
-    await terminateJob(mockStream);
-  });
-
-  it('terminates the worker', async () => {
-    const mockStream = new MockPostMessageStream();
-
-    const executor = WebWorkerPool.initialize(mockStream, WORKER_URL);
-
-    // Send ping to ensure that the worker is created.
-    writeMessage(mockStream, {
-      name: 'command',
-      data: {
-        jsonrpc: '2.0',
-        id: 1,
-        method: 'ping',
-      },
-    });
-
-    // Wait for the response, so that we know the worker is created.
-    await getResponse(mockStream);
-
-    const worker = executor.jobs.get(MOCK_JOB_ID);
-
-    assert(worker);
-    const terminateSpy = spy(worker.worker, 'terminate');
-
-    await terminateJob(mockStream);
-
-    expect(executor.jobs.get(MOCK_JOB_ID)).toBeUndefined();
-    expect(terminateSpy.calls).toHaveLength(1);
-  });
-
-  it('creates a worker pool', async () => {
-    const mockStream = new MockPostMessageStream();
-
-    const executor = WebWorkerPool.initialize(mockStream, WORKER_URL);
-    expect(executor.pool).toHaveLength(0);
-
-    // Send ping to ensure that the worker is created.
-    writeMessage(mockStream, {
-      name: 'command',
-      data: {
-        jsonrpc: '2.0',
-        id: 1,
-        method: 'ping',
-      },
-    });
-
-    // Wait for the response, so that we know the worker is created.
-    await getResponse(mockStream);
-
-    expect(executor.pool).toHaveLength(3);
-    const nextWorker = executor.pool[0];
-
-    writeMessage(
-      mockStream,
-      {
-        name: 'command',
-        data: {
-          jsonrpc: '2.0',
-          id: 2,
-          method: 'ping',
-        },
-      },
-      'job-id-2',
-    );
-
-    // Wait for the response, so that we know the worker is created.
-    await getResponse(mockStream);
-
-    expect(executor.pool).toHaveLength(3);
-    expect(executor.pool[0]).not.toBe(nextWorker);
-  });
-
-  it('handles errors', async () => {
-    const mockStream = new MockPostMessageStream();
-
-    const fetchSpy = spy(globalThis, 'fetch').mockImplementation(() => {
-      throw new Error('Failed to fetch.');
-    });
-
-    WebWorkerPool.initialize(mockStream, WORKER_URL);
-
-    writeMessage(mockStream, {
-      name: 'command',
-      data: {
-        jsonrpc: '2.0',
-        id: 1,
-        method: 'ping',
-      },
-    });
-
-    // Wait for the response, so that we know the worker is created.
-    const response = await getResponse(mockStream);
-    expect(response).toStrictEqual({
-      jsonrpc: '2.0',
-      id: null,
-      error: {
-        code: -32000,
-        message: 'Internal error',
-      },
-    });
-
-    expect(fetchSpy.calls).toHaveLength(1);
-  });
-});
diff --git a/packages/snaps-execution-environments/src/webworker/pool/WebWorkerPool.ts b/packages/snaps-execution-environments/src/webworker/pool/WebWorkerPool.ts
deleted file mode 100644
index ffdb165687..0000000000
--- a/packages/snaps-execution-environments/src/webworker/pool/WebWorkerPool.ts
+++ /dev/null
@@ -1,211 +0,0 @@
-import type { BasePostMessageStream } from '@metamask/post-message-stream';
-import {
-  WebWorkerParentPostMessageStream,
-  WindowPostMessageStream,
-} from '@metamask/post-message-stream';
-import { logError } from '@metamask/snaps-utils';
-import type { JsonRpcRequest } from '@metamask/utils';
-import { assert } from '@metamask/utils';
-import { nanoid } from 'nanoid/non-secure';
-
-type ExecutorJob = {
-  id: string;
-  worker: Worker;
-  stream: WebWorkerParentPostMessageStream;
-};
-
-/**
- * A snap executor using the WebWorker API.
- *
- * This is not a traditional snap executor, as it does not execute snaps itself.
- * Instead, it creates a pool of webworkers for each snap execution, and sends
- * the snap execution request to the webworker. The webworker is responsible for
- * executing the snap.
- */
-export class WebWorkerPool {
-  readonly #poolSize;
-
-  readonly #stream: BasePostMessageStream;
-
-  readonly #url: string;
-
-  readonly pool: Worker[] = [];
-
-  readonly jobs: Map<string, ExecutorJob> = new Map();
-
-  #workerSourceURL?: string;
-
-  /* istanbul ignore next - Constructor arguments. */
-  static initialize(
-    stream: BasePostMessageStream = new WindowPostMessageStream({
-      name: 'child',
-      target: 'parent',
-      targetWindow: self.parent,
-      targetOrigin: '*',
-    }),
-    url = '../executor/bundle.js',
-    poolSize?: number,
-  ) {
-    return new WebWorkerPool(stream, url, poolSize);
-  }
-
-  constructor(stream: BasePostMessageStream, url: string, poolSize = 3) {
-    this.#stream = stream;
-    this.#url = url;
-    this.#poolSize = poolSize;
-
-    this.#stream.on('data', this.#onData.bind(this));
-  }
-
-  /**
-   * Handle an incoming message from the `WebWorkerExecutionService`. This
-   * assumes that the message contains a `jobId` property, and a JSON-RPC
-   * request in the `data` property.
-   *
-   * @param data - The message data.
-   * @param data.data - The JSON-RPC request.
-   * @param data.jobId - The job ID.
-   */
-  #onData(data: { data: JsonRpcRequest; jobId: string }) {
-    const { jobId, data: request } = data;
-
-    const job = this.jobs.get(jobId);
-    if (!job) {
-      // This ensures that a job is initialized before it is used. To avoid
-      // code duplication, we call the `#onData` method again, which will
-      // run the rest of the logic after initialization.
-      this.#initializeJob(jobId)
-        .then(() => {
-          this.#onData(data);
-        })
-        .catch((error) => {
-          logError('[Worker] Error initializing job:', error.toString());
-
-          this.#stream.write({
-            jobId,
-            data: {
-              name: 'command',
-              data: {
-                jsonrpc: '2.0',
-                id: request.id ?? null,
-                error: {
-                  code: -32000,
-                  message: 'Internal error',
-                },
-              },
-            },
-          });
-        });
-
-      return;
-    }
-
-    // This is a method specific to the `WebWorkerPool`, as the service itself
-    // does not have access to the workers directly.
-    if (request.method === 'terminateJob') {
-      this.#terminateJob(jobId);
-      return;
-    }
-
-    job.stream.write(request);
-  }
-
-  /**
-   * Create a new worker and set up a stream to communicate with it.
-   *
-   * @param jobId - The job ID.
-   * @returns The job.
-   */
-  async #initializeJob(jobId: string): Promise<ExecutorJob> {
-    const worker = await this.#getWorker();
-    const jobStream = new WebWorkerParentPostMessageStream({
-      worker,
-    });
-
-    // Write messages from the worker to the parent, wrapped with the job ID.
-    jobStream.on('data', (data) => {
-      this.#stream.write({ data, jobId });
-    });
-
-    const job = { id: jobId, worker, stream: jobStream };
-    this.jobs.set(jobId, job);
-    return job;
-  }
-
-  /**
-   * Terminate the job with the given ID. This will close the worker and delete
-   * the job from the internal job map.
-   *
-   * @param jobId - The job ID.
-   */
-  #terminateJob(jobId: string) {
-    const job = this.jobs.get(jobId);
-    assert(job, `Job "${jobId}" not found.`);
-
-    job.stream.destroy();
-    job.worker.terminate();
-
-    this.jobs.delete(jobId);
-  }
-
-  /**
-   * Get a worker from the pool. A new worker will be created automatically.
-   *
-   * @returns The worker.
-   */
-  async #getWorker() {
-    // Lazily create the pool of workers.
-    if (this.pool.length === 0) {
-      await this.#updatePool();
-    }
-
-    const worker = this.pool.shift();
-    assert(worker, 'Worker not found.');
-
-    await this.#updatePool();
-
-    return worker;
-  }
-
-  /**
-   * Update the pool of workers. This will create new workers if the pool is
-   * below the minimum size.
-   */
-  async #updatePool() {
-    while (this.pool.length < this.#poolSize) {
-      const worker = await this.#createWorker();
-      this.pool.push(worker);
-    }
-  }
-
-  /**
-   * Create a new worker. This will fetch the worker source if it has not
-   * already been fetched.
-   *
-   * @returns The worker.
-   */
-  async #createWorker() {
-    return new Worker(await this.#getWorkerURL(), {
-      name: `worker-${nanoid()}`,
-    });
-  }
-
-  /**
-   * Get the URL of the worker source. This will fetch the worker source if it
-   * has not already been fetched.
-   *
-   * @returns The worker source URL, as a `blob:` URL.
-   */
-  async #getWorkerURL() {
-    if (this.#workerSourceURL) {
-      return this.#workerSourceURL;
-    }
-
-    const blob = await fetch(this.#url)
-      .then(async (response) => response.blob())
-      .then(URL.createObjectURL.bind(URL));
-
-    this.#workerSourceURL = blob;
-    return blob;
-  }
-}
diff --git a/packages/snaps-execution-environments/src/webworker/pool/index.ts b/packages/snaps-execution-environments/src/webworker/pool/index.ts
deleted file mode 100644
index 7d85d1c642..0000000000
--- a/packages/snaps-execution-environments/src/webworker/pool/index.ts
+++ /dev/null
@@ -1,9 +0,0 @@
-import { WebWorkerPool } from './WebWorkerPool';
-import { executeLockdownEvents } from '../../common/lockdown/lockdown-events';
-import { executeLockdownMore } from '../../common/lockdown/lockdown-more';
-
-// Lockdown is already applied in LavaMoat
-executeLockdownMore();
-executeLockdownEvents();
-
-WebWorkerPool.initialize();
diff --git a/packages/snaps-execution-environments/webpack.config.js b/packages/snaps-execution-environments/webpack.config.js
index 79e76313fa..da124f8855 100644
--- a/packages/snaps-execution-environments/webpack.config.js
+++ b/packages/snaps-execution-environments/webpack.config.js
@@ -133,24 +133,6 @@ const ENTRY_POINTS = [
       ],
     },
   },
-
-  {
-    name: 'worker-executor',
-    entry: './src/webworker/executor/index.ts',
-    inline: true,
-
-    config: {
-      target: 'webworker',
-    },
-  },
-
-  {
-    name: 'worker-pool',
-    entry: './src/webworker/pool/index.ts',
-    scuttleGlobalThis: true,
-
-    config: DEFAULT_WEB_CONFIG,
-  },
 ];
 
 /**
diff --git a/yarn.lock b/yarn.lock
index 2dfd8aef4f..8cb9c52106 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -4321,7 +4321,6 @@ __metadata:
     jest-fetch-mock: "npm:^3.0.3"
     jest-silent-reporter: "npm:^0.6.0"
     lavamoat: "npm:^9.0.8"
-    nanoid: "npm:^3.3.10"
     prettier: "npm:^3.3.3"
     readable-stream: "npm:^3.6.2"
     rimraf: "npm:^4.1.2"
@@ -11603,6 +11602,18 @@ __metadata:
   languageName: node
   linkType: hard
 
+"fdir@npm:^6.4.2":
+  version: 6.4.3
+  resolution: "fdir@npm:6.4.3"
+  peerDependencies:
+    picomatch: ^3 || ^4
+  peerDependenciesMeta:
+    picomatch:
+      optional: true
+  checksum: 10/8e6d20f4590dc168de1374a9cadaa37e20ca6e0b822aa247c230e7ea1d9e9674a68cd816146435e4ecc98f9285091462ab7e5e56eebc9510931a1794e4db68b2
+  languageName: node
+  linkType: hard
+
 "fdir@npm:^6.4.4":
   version: 6.4.4
   resolution: "fdir@npm:6.4.4"
@@ -18455,7 +18466,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"tinyglobby@npm:^0.2.13, tinyglobby@npm:^0.2.9":
+"tinyglobby@npm:^0.2.13":
   version: 0.2.13
   resolution: "tinyglobby@npm:0.2.13"
   dependencies:
@@ -18465,6 +18476,16 @@ __metadata:
   languageName: node
   linkType: hard
 
+"tinyglobby@npm:^0.2.9":
+  version: 0.2.10
+  resolution: "tinyglobby@npm:0.2.10"
+  dependencies:
+    fdir: "npm:^6.4.2"
+    picomatch: "npm:^4.0.2"
+  checksum: 10/10c976866d849702edc47fc3fef27d63f074c40f75ef17171ecc1452967900699fa1e62373681dd58e673ddff2e3f6094bcd0a2101e3e4b30f4c2b9da41397f2
+  languageName: node
+  linkType: hard
+
 "tinypool@npm:^1.0.2":
   version: 1.0.2
   resolution: "tinypool@npm:1.0.2"

From 9861942d30420885946622522b3d3816ee314828 Mon Sep 17 00:00:00 2001
From: Maarten Zuidhoorn <maarten@zuidhoorn.com>
Date: Fri, 2 May 2025 14:07:50 +0200
Subject: [PATCH 2/2] Dedupe lockfile

---
 yarn.lock | 24 +-----------------------
 1 file changed, 1 insertion(+), 23 deletions(-)

diff --git a/yarn.lock b/yarn.lock
index 8cb9c52106..3c893d678c 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -11602,18 +11602,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"fdir@npm:^6.4.2":
-  version: 6.4.3
-  resolution: "fdir@npm:6.4.3"
-  peerDependencies:
-    picomatch: ^3 || ^4
-  peerDependenciesMeta:
-    picomatch:
-      optional: true
-  checksum: 10/8e6d20f4590dc168de1374a9cadaa37e20ca6e0b822aa247c230e7ea1d9e9674a68cd816146435e4ecc98f9285091462ab7e5e56eebc9510931a1794e4db68b2
-  languageName: node
-  linkType: hard
-
 "fdir@npm:^6.4.4":
   version: 6.4.4
   resolution: "fdir@npm:6.4.4"
@@ -18466,7 +18454,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"tinyglobby@npm:^0.2.13":
+"tinyglobby@npm:^0.2.13, tinyglobby@npm:^0.2.9":
   version: 0.2.13
   resolution: "tinyglobby@npm:0.2.13"
   dependencies:
@@ -18476,16 +18464,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"tinyglobby@npm:^0.2.9":
-  version: 0.2.10
-  resolution: "tinyglobby@npm:0.2.10"
-  dependencies:
-    fdir: "npm:^6.4.2"
-    picomatch: "npm:^4.0.2"
-  checksum: 10/10c976866d849702edc47fc3fef27d63f074c40f75ef17171ecc1452967900699fa1e62373681dd58e673ddff2e3f6094bcd0a2101e3e4b30f4c2b9da41397f2
-  languageName: node
-  linkType: hard
-
 "tinypool@npm:^1.0.2":
   version: 1.0.2
   resolution: "tinypool@npm:1.0.2"