From d434746a4649b69c57a2f749b4f7e848b63cedf6 Mon Sep 17 00:00:00 2001
From: "Thiago Marcos P. Santos" <thiago@mapbox.com>
Date: Tue, 16 Jun 2015 16:42:33 +0300
Subject: [PATCH] Better error messages

Use the error message passed by the error exception instead of
always reporting "Error rendering image".
---
 src/node_map.cpp | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/node_map.cpp b/src/node_map.cpp
index 89ba8d3b9..9a21decd5 100644
--- a/src/node_map.cpp
+++ b/src/node_map.cpp
@@ -229,13 +229,22 @@ void NodeMap::renderFinished() {
     assert(!image);
 
     if (error) {
+        std::string errorMessage;
+
+        try {
+            std::rethrow_exception(error);
+        } catch (const std::exception& ex) {
+            errorMessage = ex.what();
+        }
+
+        v8::Local<v8::Value> argv[] = {
+            NanError(errorMessage.c_str())
+        };
+
         // This must be empty to be prepared for the next render call.
         error = nullptr;
         assert(!error);
 
-        v8::Local<v8::Value> argv[] = {
-            NanError("Error rendering image")
-        };
         cb->Call(1, argv);
     } else if (img) {
         auto result = NanNew<v8::Object>();