fixup!

src/api/environment.cc

@@ -67,15 +67,13 @@ MaybeLocal<Value> PrepareStackTraceCallback(Local<Context> context,
   if (env == nullptr) {
     return exception->ToString(context).FromMaybe(Local<Value>());
   }
-  Realm* current_realm = Realm::GetCurrent(context);
+  Realm* realm = Realm::GetCurrent(context);
   Local<Function> prepare;
-  if (current_realm != nullptr &&
-      current_realm->kind() != Realm::Kind::kPrincipal) {
-    // If we are in a Realm that is not the principal Realm (e.g. ShadowRealm),
-    // call the realm specific prepareStackTrace callback to avoid passing the
-    // JS objects (the exception and trace) across the realm boundary with the
-    // `Error.prepareStackTrace` override.
-    prepare = current_realm->prepare_stack_trace_callback();
+  if (realm != nullptr) {
+    // If we are in a Realm, call the realm specific prepareStackTrace callback
+    // to avoid passing the JS objects (the exception and trace) across the
+    // realm boundary with the `Error.prepareStackTrace` override.
+    prepare = realm->prepare_stack_trace_callback();
   } else {
     // The context is created with ContextifyContext, call the principal
     // realm's prepareStackTrace callback.

test/parallel/test-shadow-realm-prepare-stack-trace.js

@@ -4,14 +4,20 @@
 require('../common');
 const assert = require('assert');
 
+let principalRealmPrepareStackTraceCalled = false;
+Error.prepareStackTrace = (error, trace) => {
+  principalRealmPrepareStackTraceCalled = true;
+  return `${String(error)}\n    at ${trace.join('\n    at ')}`;
+};
+
 {
   // Validates inner Error.prepareStackTrace can not leak into the outer realm.
   const shadowRealm = new ShadowRealm();
 
   const stack = shadowRealm.evaluate(`
 Error.prepareStackTrace = (error, trace) => {
   globalThis.leaked = 'inner';
-  return String(error);
+  return 'from shadow realm';
 };
 
 try {
@@ -20,7 +26,8 @@ try {
   e.stack;
 }
 `);
-  assert.strictEqual(stack, 'Error: boom');
+  assert.ok(!principalRealmPrepareStackTraceCalled);
+  assert.strictEqual(stack, 'from shadow realm');
   assert.strictEqual('leaked' in globalThis, false);
 }
 
@@ -39,6 +46,7 @@ try {
   e.stack;
 }
 `);
+  assert.ok(!principalRealmPrepareStackTraceCalled);
   const lines = stack.split('\n');
   assert.strictEqual(lines[0], 'Error: boom');
   assert.match(lines[1], /^ {4}at myFunc \(.*\)/);