fix: Throw if Snap not installed

Author: FrederikBolding

packages/snaps-controllers/src/snaps/SnapController.test.tsx

@@ -2192,6 +2192,27 @@ describe('SnapController', () => {
   });
 
   describe('handleRequest', () => {
+    it('throws if the Snap is not installed', async () => {
+      const snapController = getSnapController();
+
+      await expect(
+        snapController.handleRequest({
+          snapId: 'npm:foo' as SnapId,
+          origin: METAMASK_ORIGIN,
+          handler: HandlerType.OnUserInput,
+          request: {
+            jsonrpc: '2.0',
+            method: 'test',
+            params: { id: MOCK_INTERFACE_ID },
+          },
+        }),
+      ).rejects.toThrow(
+        'The Snap "npm:foo" is not installed. Please install it before invoking it.',
+      );
+
+      snapController.destroy();
+    });
+
     it.each(
       Object.keys(handlerEndowments).filter(
         (handler) => handlerEndowments[handler as HandlerType],

packages/snaps-controllers/src/snaps/SnapController.ts

@@ -3588,6 +3588,13 @@ export class SnapController extends BaseController<
   }: SnapRpcHookArgs & { snapId: SnapId }): Promise<unknown> {
     this.#assertCanUsePlatform();
 
+    const snap = this.get(snapId);
+
+    assert(
+      snap,
+      `The Snap "${snapId}" is not installed. Please install it before invoking it.`,
+    );
+
     assert(
       origin === METAMASK_ORIGIN || isValidUrl(origin),
       "'origin' must be a valid URL or 'metamask'.",
@@ -3666,11 +3673,11 @@ export class SnapController extends BaseController<
       throw new Error(`"${handlerType}" can only be invoked by MetaMask.`);
     }
 
-    if (!this.state.snaps[snapId].enabled) {
+    if (!snap.enabled) {
       throw new Error(`Snap "${snapId}" is disabled.`);
     }
 
-    if (this.state.snaps[snapId].status === SnapStatus.Installing) {
+    if (snap.status === SnapStatus.Installing) {
       throw new Error(
         `Snap "${snapId}" is currently being installed. Please try again later.`,
       );