fix(ses): re-exported names available in imported modules

This fixes a situation in which module _A_ re-exports name _X_ from module _B_, and then imports module _C_, which in turn imports _X_ from _A_.

Originally encountered in the source code for `terser`.

Author: boneskull

packages/ses/src/module-instance.js

@@ -26,6 +26,8 @@ import { compartmentEvaluate } from './compartment-evaluate.js';
 
 const { quote: q } = assert;
 
+let id = 0;
+
 export const makeVirtualModuleInstance = (
   compartmentPrivateFields,
   moduleSource,
@@ -372,26 +374,14 @@ export const makeModuleInstance = (
     // export * cannot export default.
     const candidateAll = create(null);
     candidateAll.default = false;
-    for (const [specifier, importUpdaters] of updateRecord) {
+
+    for (const [specifier] of updateRecord) {
       const instance = mapGet(importedInstances, specifier);
       // The module instance object is an internal literal, does not bind this,
       // and never revealed outside the SES shim.
       // There are two instantiation sites for instances and they are both in
       // this module.
-      // eslint-disable-next-line @endo/no-polymorphic-call
-      instance.execute(); // bottom up cycle tolerant
       const { notifiers: importNotifiers } = instance;
-      for (const [importName, updaters] of importUpdaters) {
-        const importNotify = importNotifiers[importName];
-        if (!importNotify) {
-          throw SyntaxError(
-            `The requested module '${specifier}' does not provide an export named '${importName}'`,
-          );
-        }
-        for (const updater of updaters) {
-          importNotify(updater);
-        }
-      }
       if (arrayIncludes(exportAlls, specifier)) {
         // Make all these imports candidates.
         // Note names don't change in reexporting all
@@ -433,6 +423,26 @@ export const makeModuleInstance = (
       }
     }
 
+    // this must happen _after_ the previous loop so that re-exported names
+    // have associated import notifiers
+    for (const [specifier, importUpdaters] of updateRecord) {
+      const instance = mapGet(importedInstances, specifier);
+      // eslint-disable-next-line @endo/no-polymorphic-call
+      instance.execute(); // bottom up cycle tolerant
+      const { notifiers: importNotifiers } = instance;
+      for (const [importName, updaters] of importUpdaters) {
+        const importNotify = importNotifiers[importName];
+        if (!importNotify) {
+          throw SyntaxError(
+            `The requested module '${specifier}' does not provide an export named '${importName}'`,
+          );
+        }
+        for (const updater of updaters) {
+          importNotify(updater);
+        }
+      }
+    }
+
     // Sort the module exports namespace as per spec.
     // The module exports namespace will be wrapped in a module namespace
     // exports proxy which will serve as a "module exports namespace exotic
@@ -493,5 +503,6 @@ export const makeModuleInstance = (
     notifiers,
     exportsProxy,
     execute,
+    id: (id += 1),
   });
 };

packages/ses/test/import-gauntlet.test.js

@@ -406,3 +406,31 @@ test('this in module scope must be undefined', async t => {
 
   await compartment.import('./index.js');
 });
+
+test('re-exported names should available in imported modules', async t => {
+  t.plan(1);
+
+  const makeImportHook = makeNodeImporter({
+    'https://example.com/index.js': `
+      export { a } from './a.js';   
+      import './c.js';
+    `,
+    'https://example.com/a.js': `
+      export const a = 'a';
+    `,
+    'https://example.com/c.js': `
+      import { a } from './index.js';
+      t.is(a, 'a', 're-exported name "a" from importing module should be string "a"');
+    `,
+  });
+  const importHook = makeImportHook('https://example.com');
+
+  const compartment = new Compartment({
+    globals: { t },
+    resolveHook: resolveNode,
+    importHook,
+    __options__: true,
+  });
+
+  await compartment.import('./index.js');
+});