From ca1db22c95f3fff2ff9498cde967b279d20eac66 Mon Sep 17 00:00:00 2001
From: John French <johnfrench093@gmail.com>
Date: Mon, 2 Apr 2018 20:13:41 -0400
Subject: [PATCH] don't try to escape null

If an exception is pending from Call Or MakeCallback on
FunctionReference the return value may be nullptr.
Check for a pending exception and don't try to escape in these cases.

PR-URL: https://github.com/nodejs/node-addon-api/pull/245
Refs: https://github.com/nodejs/node-addon-api/issues/233
Reviewed-By: Hitesh Kanwathirtha <hiteshk@microsoft.com>
---
 napi-inl.h | 36 ++++++++++++++++++++++++++++++------
 1 file changed, 30 insertions(+), 6 deletions(-)

diff --git a/napi-inl.h b/napi-inl.h
index b3ac0ec..884f8cb 100644
--- a/napi-inl.h
+++ b/napi-inl.h
@@ -2285,36 +2285,60 @@ inline Napi::Value FunctionReference::operator ()(
 
 inline Napi::Value FunctionReference::Call(const std::initializer_list<napi_value>& args) const {
   EscapableHandleScope scope(_env);
-  return scope.Escape(Value().Call(args));
+  Napi::Value result = Value().Call(args);
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
 }
 
 inline Napi::Value FunctionReference::Call(const std::vector<napi_value>& args) const {
   EscapableHandleScope scope(_env);
-  return scope.Escape(Value().Call(args));
+  Napi::Value result = Value().Call(args);
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
 }
 
 inline Napi::Value FunctionReference::Call(
     napi_value recv, const std::initializer_list<napi_value>& args) const {
   EscapableHandleScope scope(_env);
-  return scope.Escape(Value().Call(recv, args));
+  Napi::Value result = Value().Call(recv, args);
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
 }
 
 inline Napi::Value FunctionReference::Call(
     napi_value recv, const std::vector<napi_value>& args) const {
   EscapableHandleScope scope(_env);
-  return scope.Escape(Value().Call(recv, args));
+  Napi::Value result = Value().Call(recv, args);
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
 }
 
 inline Napi::Value FunctionReference::MakeCallback(
     napi_value recv, const std::initializer_list<napi_value>& args) const {
   EscapableHandleScope scope(_env);
-  return scope.Escape(Value().MakeCallback(recv, args));
+  Napi::Value result = Value().MakeCallback(recv, args);
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
 }
 
 inline Napi::Value FunctionReference::MakeCallback(
     napi_value recv, const std::vector<napi_value>& args) const {
   EscapableHandleScope scope(_env);
-  return scope.Escape(Value().MakeCallback(recv, args));
+  Napi::Value result = Value().MakeCallback(recv, args);
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
 }
 
 inline Object FunctionReference::New(const std::initializer_list<napi_value>& args) const {