core-api: avoid exporting AnyRoutes, AnyExternalRoutes, and ExternalRouteRef constructor

packages/core-api/src/app/types.ts

@@ -16,7 +16,7 @@
 
 import { ComponentType } from 'react';
 import { IconComponent, SystemIconKey, SystemIcons } from '../icons';
-import { BackstagePlugin, AnyExternalRoutes } from '../plugin';
+import { BackstagePlugin, AnyExternalRoutes } from '../plugin/types';
 import { RouteRef } from '../routing';
 import { AnyApiFactory } from '../apis';
 import { AppTheme, ProfileInfo } from '../apis/definitions';

packages/core-api/src/plugin/index.ts

@@ -15,4 +15,19 @@
  */
 
 export { createPlugin } from './Plugin';
-export * from './types';
+export type {
+  BackstagePlugin,
+  Extension,
+  FeatureFlagOutput,
+  FeatureFlagsHooks,
+  LegacyRedirectRouteOutput,
+  LegacyRouteOutput,
+  PluginConfig,
+  PluginHooks,
+  PluginOutput,
+  RedirectRouteOutput,
+  RouteOptions,
+  RouteOutput,
+  RoutePath,
+  RouterHooks,
+} from './types';

packages/core-api/src/routing/RouteRef.ts

@@ -54,12 +54,20 @@ export function createRouteRef<
   return new AbsoluteRouteRef<Params>(config);
 }
 
+const create = Symbol('create-external-route-ref');
+
 export class ExternalRouteRef {
+  static [create]() {
+    return new ExternalRouteRef();
+  }
+
+  private constructor() {}
+
   toString() {
     return `externalRouteRef{}`;
   }
 }
 
 export function createExternalRouteRef(): ExternalRouteRef {
-  return new ExternalRouteRef();
+  return ExternalRouteRef[create]();
 }