CLI export-dynamic-plugin fails after backstage update

[johanneswuerbach]

Describe the bug

Trying the export a package with @janus-idp/[email protected] package export-dynamic-plugin --clean fails with an error after updating backstage using yarn backstage-cli versions:bump --release 1.27.7:

Error: Backend plugin is not valid for dynamic loading: it should either export a BackendFeature or BackendFeatureFactory as default export, or export a const dynamicPluginInstaller: BackendDynamicPluginInstaller field as dynamic loading entrypoint

Expected Behavior

@janus-idp/[email protected] package export-dynamic-plugin --clean should work as before.

Debugging

There has been an upstream change backstage/backstage#25098, which is potentially affecting the validate export detection logic of the CLI

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

Lines 101 to 123 in 582cf36

	export function isValidPluginModule(pluginModule: any): boolean {
	return (
	isBackendFeature(pluginModule?.default) ||
	isBackendFeatureFactory(pluginModule?.default) ||
	isBackendDynamicPluginInstaller(pluginModule?.dynamicPluginInstaller)
	);
	}
	function isBackendFeature(value: unknown): boolean {
	return (
	!!value &&
	typeof value === 'object' &&
	(value as any).$$type === '@backstage/BackendFeature'
	);
	}
	function isBackendFeatureFactory(value: unknown): boolean {
	return (
	!!value &&
	typeof value === 'function' &&
	(value as any).$$type === '@backstage/BackendFeatureFactory'
	);
	}

.

Sadly this upstream change has been released as a patch release, so everyone locking to ^0.6.x will soon get this change.

Locking the version "@backstage/backend-plugin-api": "0.6.18" inside the package.json of the respective plugin fixes the build.

[gashcrumb]

FYI this has been fixed by #2059, thanks @JessicaJHee