fix nested render error message

src/util/error.js

@@ -31,6 +31,10 @@ ParseError.prototype = Object.create(Error.prototype);
 ParseError.prototype.constructor = ParseError;
 
 function RenderError(e, tpl) {
+    // return the original render error
+    if(e instanceof RenderError){
+        return e;
+    }
     this.name = this.constructor.name;
     this.stack = e.stack;
 

test/util/error.js

@@ -10,6 +10,9 @@ var strictEngine = require('../..')({
 });
 
 describe('error', function() {
+    afterEach(function(){
+        mock.restore();
+    });
 
     describe('TokenizationError', function() {
         it('should throw TokenizationError when tag illegal', function() {
@@ -78,7 +81,9 @@ describe('error', function() {
 
     describe('RenderError', function() {
         beforeEach(function() {
-            engine = require('../..')();
+            engine = require('../..')({
+                root: '/'
+            });
             engine.registerTag('throwingTag', {
                 render: function() {
                     throw new Error('intended render error');
@@ -131,7 +136,7 @@ describe('error', function() {
                     expect(e.message).to.contain('undefined variable: a');
                 });
         });
-        it('should contain template content in err.message', function() {
+        it('should contain template context in err.stack', function() {
             var html = ['1st', '2nd', '3rd', 'X{%throwingTag%} Y', '5th', '6th', '7th'];
             var message = [
                 '   2| 2nd',
@@ -150,6 +155,31 @@ describe('error', function() {
                     expect(err.name).to.equal('RenderError');
                 });
         });
+        it.only('should contain original template context in err.stack', function() {
+            var origin = ['1st', '2nd', '3rd', 'X{%throwingTag%} Y', '5th', '6th', '7th'];
+            mock({
+                '/throwing-tag.html': origin.join('\n')
+            });
+            var html = '{%include "throwing-tag.html"%}';
+            var message = [
+                '   2| 2nd',
+                '   3| 3rd',
+                '>> 4| X{%throwingTag%} Y',
+                '   5| 5th',
+                '   6| 6th',
+                '   7| 7th',
+                'Error: intended render error',
+            ];
+            return expect(engine.parseAndRender(html)).to.eventually
+                .be.rejected
+                .then(function(err) {
+                    console.log(err.message);
+                    console.log(err.stack);
+                    expect(err.message).to.equal('intended render error, line:4');
+                    expect(err.stack).to.contain(message.join('\n'));
+                    expect(err.name).to.equal('RenderError');
+                });
+        });
         it('should contain the whole template content in err.input', function() {
             var html = 'bar\nfoo{%throwingTag%}\nfoo';
             return expect(engine.parseAndRender(html)).to.eventually
@@ -245,7 +275,7 @@ describe('error', function() {
                 });
         });
 
-        it('should contain template content in err.message', function() {
+        it('should contain template context in err.stack', function() {
             var html = ['1st', '2nd', '3rd', 'X{% a %} {% enda %} Y', '5th', '6th', '7th'];
             var message = [
                 '   2| 2nd',