fix(cli): do not change interop mode by default

but provide an additional CLI argument to change it
per imported package.
Also include the related `./alpha` package when embedding a package.

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

packages/cli/src/commands/export-dynamic-plugin/backend.ts

@@ -21,7 +21,7 @@ import { loadConfig } from '@backstage/config-loader';
 import { getPackages } from '@manypkg/get-packages';
 import { OptionValues } from 'commander';
 import fs from 'fs-extra';
-import { rollup } from 'rollup';
+import { InteropType, rollup } from 'rollup';
 import * as semver from 'semver';
 
 import { execSync } from 'child_process';
@@ -102,6 +102,8 @@ export async function backend(
       if (relatedCommonPackage !== pkgToEmbed) {
         mergeWithOutput.push(relatedCommonPackage);
       }
+      const relatedAlphaPackage = pkgToEmbed.concat('/alpha');
+      mergeWithOutput.push(relatedAlphaPackage);
     }
   }
 
@@ -125,6 +127,21 @@ export async function backend(
     .map(p => p.slice(1))
     .map(stringOrRegexp);
 
+  let interopForAll: InteropType | undefined = undefined;
+  const interopForPackage: { [key: string]: InteropType } = {};
+  for (const mode in opts.overrideInterop) {
+    if (!Object.prototype.hasOwnProperty.call(opts.overrideInterop, mode)) {
+      continue;
+    }
+
+    if (!opts.overrideInterop[mode]?.length) {
+      interopForAll = mode as InteropType;
+    }
+    for (const interopPkg of opts.overrideInterop[mode]) {
+      interopForPackage[interopPkg] = mode as InteropType;
+    }
+  }
+
   const rollupConfigs = await makeRollupConfigs({
     outputs,
     minify: Boolean(opts.minify),
@@ -189,7 +206,20 @@ export async function backend(
   if (Array.isArray(rollupConfig.output)) {
     rollupConfig.output.forEach(output => {
       if (output.format === 'commonjs') {
-        output.interop = 'default';
+        if (interopForAll) {
+          console.log(
+            `Overriding Interop to '${interopForAll}' for all imports`,
+          );
+        }
+        output.interop = (id: string | null) => {
+          if (id && interopForPackage[id]) {
+            console.log(
+              `Overriding Interop to '${interopForPackage[id]}' for '${id}'`,
+            );
+            return interopForPackage[id];
+          }
+          return interopForAll || true; // true is the default value in Rollup.
+        };
       }
     });
   }

packages/cli/src/commands/index.ts

@@ -16,7 +16,7 @@
 
 import { assertError } from '@backstage/errors';
 
-import { Command } from 'commander';
+import { Command, InvalidArgumentError } from 'commander';
 
 import { exitWithError } from '../lib/errors';
 
@@ -87,6 +87,20 @@ export function registerScriptCommand(program: Command) {
       '--shared-package [package-name...]',
       'Optional list of packages that should be considered shared by all dynamic plugins, and will be moved to peer dependencies of the dynamic plugin. The `@backstage` packages are by default considered shared dependencies.',
     )
+    .option(
+      '--override-interop <mode:package-name,package-name...>',
+      'Optional list of packages for which the CommonJS Rollup output interop mode should be overridden to `mode` when building the dynamic plugin assets (backend plugin only).',
+      (value, previous) => {
+        const [key, val] = value.split(':');
+        if (!['auto', 'esModule', 'default', 'defaultOnly'].includes(key)) {
+          throw new InvalidArgumentError(
+            `Invalid interop mode '${key}'. Possible values are: auto, esModule, default, defaultOnly (see https://rollupjs.org/configuration-options/#output-interop).`,
+          );
+        }
+        return { ...previous, [key]: val?.split(',') || [] };
+      },
+      {},
+    )
     .option(
       '--no-install',
       'Do not run `yarn install` to fill the dynamic plugin `node_modules` folder (backend plugin only).',

packages/cli/src/lib/builder/embedPlugin.ts

@@ -54,6 +54,9 @@ export function embedModules(options: EmbedModulesOptions): Plugin {
         return;
       }
       for (const e of embedded) {
+        if (e.endsWith('/alpha')) {
+          continue;
+        }
         const mod = await this.resolve(
           path.join(e, 'package.json'),
           undefined,