fix(ptc-runtime-node): preserve native then-export results

packages/ptc-runtime/ptc-runtime-node/src/imports/vm-modules.ts

@@ -1,5 +1,6 @@
 /** Adapt runner-local import decisions to Node's VM module callbacks. */
 import * as vm from 'node:vm'
+import { types } from 'node:util'
 import type { ImportAttributes } from 'node:module'
 import type { ProgramImportHandler } from '../evaluators/types.ts'
 
@@ -56,7 +57,10 @@ export class VmModuleImportLoader {
       nativeImport ??= vm.compileFunction('return import(specifier, { with: attributes })', ['specifier', 'attributes'], {
         filename, importModuleDynamically: vm.constants.USE_MAIN_CONTEXT_DEFAULT_LOADER,
       }) as NativeImport
-      return nativeImport(specifier, attributes)
+      const value = await nativeImport(specifier, attributes)
+      if (types.isModuleNamespaceObject(value)) return value
+      // A native then export can settle to any value; the VM callback still requires a module.
+      return this.module({ then(resolve: (result: unknown) => void) { resolve(value) } })
     }
     // Node accepts namespace objects as well as vm.Module; the Node types declare only vm.Module.
     return load as vm.DynamicModuleLoader<object>

packages/ptc-runtime/ptc-runtime-node/tests/imports.spec.ts

@@ -125,6 +125,14 @@ it.each(formats)('preserves JavaScript then-export assimilation in %s', async (f
   else expect(await e.expression('import("runner:then")')).toBe(42)
 })
 
+it.each(['default', 'redirect'] as const)('preserves native then-export results through Script %s loading', async (decision) => {
+  const specifier = 'data:text/javascript,export function then(resolve) { resolve({ answer() { return 42 } }) }'
+  const handler = vi.fn((): ProgramImportResult => decision === 'default' ? { type: 'default' } : { type: 'redirect', specifier })
+  const e = evaluator('script', handler)
+  expect(await e.expression(`(await import(${JSON.stringify(decision === 'default' ? specifier : 'runner:then')})).answer()`)).toBe(42)
+  expect(handler).toHaveBeenCalledTimes(1)
+})
+
 it('keeps async-function grammar and parameter semantics when imports are intercepted', async () => {
   const e = evaluator('function-body', () => ({ type: 'default' }))
   e.globals.answer = 42