vm: don't print out arrow message for custom error

src/node.cc

@@ -1423,7 +1423,8 @@ bool IsExceptionDecorated(Environment* env, Local<Value> er) {
 
 void AppendExceptionLine(Environment* env,
  Local<Value> er,
- Local<Message> message) {
+ Local<Message> message,
+ enum ErrorHandlingMode mode) {
  if (message.IsEmpty())
  return;
 
@@ -1510,20 +1511,26 @@ void AppendExceptionLine(Environment* env,
 
  Local<String> arrow_str = String::NewFromUtf8(env->isolate(), arrow);
 
- if (!arrow_str.IsEmpty() && !err_obj.IsEmpty() && err_obj->IsNativeError()) {
- err_obj->SetPrivate(
- env->context(),
- env->arrow_message_private_symbol(),
- arrow_str);
+ const bool can_set_arrow = !arrow_str.IsEmpty() && !err_obj.IsEmpty();
+ // If allocating arrow_str failed, print it out. There's not much else to do.
+ // If it's not an error, but something needs to be printed out because
+ // it's a fatal exception, also print it out from here.
+ // Otherwise, the arrow property will be attached to the object and handled
+ // by the caller.
+ if (!can_set_arrow || (mode == FATAL_ERROR && !err_obj->IsNativeError())) {
+ if (env->printed_error())
+ return;
+ env->set_printed_error(true);
+
+ uv_tty_reset_mode();
+ PrintErrorString("\n%s", arrow);
  return;
  }
 
- // Allocation failed, just print it out.
- if (env->printed_error())
- return;
- env->set_printed_error(true);
- uv_tty_reset_mode();
- PrintErrorString("\n%s", arrow);
+ CHECK(err_obj->SetPrivate(
+ env->context(),
+ env->arrow_message_private_symbol(),
+ arrow_str).FromMaybe(false));
 }
 
 
@@ -1532,7 +1539,7 @@ static void ReportException(Environment* env,
  Local<Message> message) {
  HandleScope scope(env->isolate());
 
- AppendExceptionLine(env, er, message);
+ AppendExceptionLine(env, er, message, FATAL_ERROR);
 
  Local<Value> trace_value;
  Local<Value> arrow;

src/node_contextify.cc

@@ -632,7 +632,7 @@ class ContextifyScript : public BaseObject {
  if (IsExceptionDecorated(env, err_obj))
  return;
 
- AppendExceptionLine(env, exception, try_catch.Message());
+ AppendExceptionLine(env, exception, try_catch.Message(), CONTEXTIFY_ERROR);
  Local<Value> stack = err_obj->Get(env->stack_string());
  auto maybe_value =
  err_obj->GetPrivate(

src/node_internals.h

@@ -137,9 +137,11 @@ constexpr size_t arraysize(const T(&)[N]) { return N; }
 
 bool IsExceptionDecorated(Environment* env, v8::Local<v8::Value> er);
 
+enum ErrorHandlingMode { FATAL_ERROR, CONTEXTIFY_ERROR };
 void AppendExceptionLine(Environment* env,
  v8::Local<v8::Value> er,
- v8::Local<v8::Message> message);
+ v8::Local<v8::Message> message,
+ enum ErrorHandlingMode mode);
 
 NO_RETURN void FatalError(const char* location, const char* message);
 

test/message/vm_caught_custom_runtime_error.js

@@ -0,0 +1,18 @@
+'use strict';
+require('../common');
+const vm = require('vm');
+
+console.error('beginning');
+
+// Regression test for https://github.com/nodejs/node/issues/7397:
+// vm.runInThisContext() should not print out anything to stderr by itself.
+try {
+ vm.runInThisContext(`throw ({
+ name: 'MyCustomError',
+ message: 'This is a custom message'
+ })`, { filename: 'test.vm' });
+} catch (e) {
+ console.error('received error', e.name);
+}
+
+console.error('end');

test/message/vm_caught_custom_runtime_error.out

@@ -0,0 +1,3 @@
+beginning
+received error MyCustomError
+end