fix review comments

Signed-off-by: David Festal <dfestal@redhat.com>

packages/backend-dynamic-feature-service/src/scanner/plugin-scanner.test.ts

@@ -544,7 +544,7 @@ Please add '${mockDir.resolve(
             {
               message: `failed to load dynamic plugin manifest from '${mockDir.resolve(
                 'backstageRoot/dist-dynamic/test-backend-plugin/alpha',
-              )}'`,
+              )}'; caused by SyntaxError: Unexpected token 'i', "invalid js"... is not valid JSON`,
               meta: {
                 name: 'SyntaxError',
                 message: expect.stringContaining('Unexpected token'),

packages/backend-dynamic-feature-service/src/scanner/plugin-scanner.ts

@@ -22,6 +22,7 @@ import * as path from 'path';
 import * as url from 'url';
 import debounce from 'lodash/debounce';
 import { LoggerService } from '@backstage/backend-plugin-api';
+import { ForwardedError } from '@backstage/errors';
 
 export interface DynamicPluginScannerOptions {
   config: Config;
@@ -36,15 +37,6 @@ export interface ScanRootResponse {
 
 export const configKey = 'dynamicPlugins';
 
-class WrappedError extends Error {
-  wrapped: Error;
-
-  constructor(message: string, wrapped: Error) {
-    super(message);
-    this.wrapped = wrapped;
-  }
-}
-
 export class PluginScanner {
   private _rootDirectory?: string;
   private configUnsubscribe?: () => void;
@@ -178,8 +170,8 @@ export class PluginScanner {
           throw new Error("field 'backstage.role' not found in 'package.json'");
         }
       } catch (e) {
-        if (e instanceof WrappedError) {
-          this.logger.error(e.message, e.wrapped);
+        if (e instanceof ForwardedError) {
+          this.logger.error(e.message, e.cause);
         } else {
           this.logger.error(
             `failed to load dynamic plugin manifest from '${pluginHome}'`,
@@ -214,7 +206,7 @@ export class PluginScanner {
               alphaContent.toString(),
             );
           } catch (e) {
-            throw new WrappedError(
+            throw new ForwardedError(
               `failed to load dynamic plugin manifest from '${pluginHome}/alpha'`,
               e,
             );