Allow explicit package list & add UI

Co-authored-by: Vincenzo Scamporlino <vinzscam@users.noreply.github.com>
Signed-off-by: Philipp Hugenroth <philipph@spotify.com>

packages/cli/src/lib/bundler/config.ts

@@ -131,7 +131,7 @@ export async function createConfig(
 
   if (extraPackages.length > 0) {
     const requirePackageScript = extraPackages
-      ?.map(pkg => `require('${pkg}')`)
+      ?.map(pkg => `{name: '${pkg}', module: require('${pkg}')}`)
       .join(',');
 
     plugins.push(

packages/cli/src/lib/bundler/server.ts

@@ -42,7 +42,7 @@ export async function serveBundle(options: ServeOptions) {
 
   // TODO: proper
   // Assumption for config string based on https://github.com/backstage/backstage/issues/18372 ^
-  const packageDetectionMode = options.fullConfig.getOptionalString(
+  const packageDetectionMode = options.fullConfig.getOptional(
     'app.experimental.packages',
   );
   const extraPackages = [];
@@ -60,6 +60,23 @@ export async function serveBundle(options: ServeOptions) {
         extraPackages.push(depName);
       }
     }
+  } else {
+    const packagesList = Array.isArray(packageDetectionMode)
+      ? packageDetectionMode
+      : [];
+    for (const depName of packagesList ?? []) {
+      const depPackageJson: BackstagePackageJson = require(require.resolve(
+        `${depName}/package.json`,
+        { paths: [paths.targetPath] },
+      ));
+      if (
+        ['frontend-plugin', 'frontend-plugin-module'].includes(
+          depPackageJson.backstage?.role || '',
+        )
+      ) {
+        extraPackages.push(depName);
+      }
+    }
   }
   if (options.verifyVersions) {
     const lockfile = await Lockfile.load(