refactor(extension): Update vat command validation logic

Author: rekmarks

packages/extension/src/kernel-integration/handlers/send-vat-command.ts

@@ -1,4 +1,5 @@
 import { object } from '@metamask/superstruct';
+import type { Infer } from '@metamask/superstruct';
 import { UnsafeJsonStruct } from '@metamask/utils';
 import type { Json } from '@metamask/utils';
 import { VatIdStruct } from '@ocap/kernel';
@@ -17,6 +18,8 @@ export const sendVatCommandSpec: MethodSpec<
   result: object({ result: UnsafeJsonStruct }),
 };
 
+export type SendVatCommandParams = Infer<(typeof sendVatCommandSpec)['params']>;
+
 export type SendVatCommandHooks = {
   kernel: Pick<Kernel, 'sendVatCommand'>;
 };
@@ -34,3 +37,14 @@ export const sendVatCommandHandler: Handler<
     return { result };
   },
 };
+
+/**
+ * Asserts that the given params are valid for the `sendVatCommand` method.
+ *
+ * @param params - The params to assert.
+ */
+export function assertVatCommandParams(
+  params: unknown,
+): asserts params is SendVatCommandParams {
+  sendVatCommandSpec.params.assert(params);
+}

packages/extension/src/ui/hooks/useKernelActions.test.ts

@@ -3,6 +3,10 @@ import { describe, it, expect, vi, beforeEach } from 'vitest';
 
 import clusterConfig from '../../vats/default-cluster.json';
 
+vi.mock('../../kernel-integration/handlers/send-vat-command.ts', () => ({
+  assertVatCommandParams: vi.fn(),
+}));
+
 vi.mock('../context/PanelContext.tsx', () => ({
   usePanelContext: vi.fn(),
 }));
@@ -15,7 +19,7 @@ vi.mock('@ocap/utils', async (importOriginal) => ({
 describe('useKernelActions', () => {
   const mockSendMessage = vi.fn();
   const mockLogMessage = vi.fn();
-  const mockMessageContent = '{"test": "content"}';
+  const mockMessageContent = '{"id": "v0", "payload": {"method": "test"}}';
 
   beforeEach(async () => {
     const { usePanelContext } = await import('../context/PanelContext.tsx');
@@ -35,13 +39,15 @@ describe('useKernelActions', () => {
     it('sends message with payload', async () => {
       const { useKernelActions } = await import('./useKernelActions.ts');
       const { result } = renderHook(() => useKernelActions());
-      const expectedParams = { test: 'content' };
       mockSendMessage.mockResolvedValueOnce({ success: true });
       result.current.sendKernelCommand();
       await waitFor(() => {
         expect(mockSendMessage).toHaveBeenCalledWith({
           method: 'sendVatCommand',
-          params: expectedParams,
+          params: expect.objectContaining({
+            id: 'v0',
+            payload: expect.any(Object),
+          }),
         });
       });
     });

packages/extension/src/ui/hooks/useKernelActions.ts

@@ -3,6 +3,8 @@ import type { ClusterConfig } from '@ocap/kernel';
 import { stringify } from '@ocap/utils';
 import { useCallback } from 'react';
 
+import { assertVatCommandParams } from '../../kernel-integration/handlers/send-vat-command.ts';
+import type { SendVatCommandParams } from '../../kernel-integration/handlers/send-vat-command.ts';
 import { usePanelContext } from '../context/PanelContext.tsx';
 import { nextMessageId } from '../utils.ts';
 
@@ -28,7 +30,7 @@ export function useKernelActions(): {
   const sendKernelCommand = useCallback(() => {
     callKernelMethod({
       method: 'sendVatCommand',
-      params: coerceCommandParams(JSON.parse(messageContent)),
+      params: parseCommandParams(messageContent),
     })
       .then((result) => logMessage(stringify(result, 0), 'received'))
       .catch((error) => logMessage(error.message, 'error'));
@@ -129,27 +131,29 @@ export function useKernelActions(): {
 }
 
 /**
- * Coerces sendVatCommand params to the expected format. Basically, turns the payload
+ * Parses sendVatCommand params to the expected format. Basically, turns the payload
  * into a JSON-RPC request.
  *
- * @param params - The params to coerce.
- * @returns The coerced params.
+ * @param rawParams - The raw, stringified params to parse.
+ * @returns The parsed params.
  */
-// eslint-disable-next-line @typescript-eslint/explicit-function-return-type
-function coerceCommandParams<Params>(params: Params) {
+function parseCommandParams(rawParams: string): SendVatCommandParams {
+  const params = JSON.parse(rawParams);
   if (
     isObject(params) &&
     isObject(params.payload) &&
     hasProperty(params.payload, 'method')
   ) {
-    return {
+    const parsed = {
       ...params,
       payload: {
         ...params.payload,
         id: nextMessageId(),
         jsonrpc: '2.0',
       },
     };
+    assertVatCommandParams(parsed);
+    return parsed;
   }
-  return params;
+  throw new Error('Invalid command params');
 }

vitest.config.ts

@@ -82,10 +82,10 @@ export default defineConfig({
           lines: 98.63,
         },
         'packages/extension/**': {
-          statements: 78.73,
-          functions: 81.15,
-          branches: 74.1,
-          lines: 78.72,
+          statements: 78.71,
+          functions: 80.72,
+          branches: 74.82,
+          lines: 78.7,
         },
         'packages/kernel/**': {
           statements: 89.31,