Use opaque types for command graph nodes

Switch CommandGraph and CliInitializer to use OpaqueCommandTreeNode and
OpaqueCommandLeafNode from @internal/cli instead of raw $$type markers.

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
Made-with: Cursor

packages/cli-internal/src/InternalCommandNode.ts

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2024 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { BackstageCommand } from '@backstage/cli-plugin-api';
+import { OpaqueType } from '@internal/opaque';
+
+/** @internal */
+export interface CommandTreeNode {
+  readonly $$type: '@backstage/CommandTreeNode';
+}
+
+/** @internal */
+export interface CommandLeafNode {
+  readonly $$type: '@backstage/CommandLeafNode';
+}
+
+export type CommandNode = CommandTreeNode | CommandLeafNode;
+
+export const OpaqueCommandTreeNode = OpaqueType.create<{
+  public: CommandTreeNode;
+  versions: {
+    readonly version: 'v1';
+    readonly name: string;
+    readonly children: CommandNode[];
+  };
+}>({
+  type: '@backstage/CommandTreeNode',
+  versions: ['v1'],
+});
+
+export const OpaqueCommandLeafNode = OpaqueType.create<{
+  public: CommandLeafNode;
+  versions: {
+    readonly version: 'v1';
+    readonly name: string;
+    readonly command: BackstageCommand;
+  };
+}>({
+  type: '@backstage/CommandLeafNode',
+  versions: ['v1'],
+});

packages/cli-internal/src/index.ts

@@ -15,3 +15,12 @@
  */
 
 export { OpaqueCliPlugin } from './InternalCliPlugin';
+export type {
+  CommandNode,
+  CommandTreeNode,
+  CommandLeafNode,
+} from './InternalCommandNode';
+export {
+  OpaqueCommandTreeNode,
+  OpaqueCommandLeafNode,
+} from './InternalCommandNode';