When exceptions occur in handler functions or helpers, call chunk.setError

lib/dust.js

@@ -338,7 +338,11 @@ Chunk.prototype.map = function(callback) {
 
   this.next = branch;
   this.flushable = true;
-  callback(branch);
+  try {
+    callback(branch);
+  } catch(e) {
+    branch.setError(e);
+  }
   return cursor;
 };
 
@@ -365,7 +369,7 @@ Chunk.prototype.render = function(body, context) {
 Chunk.prototype.reference = function(elem, context, auto, filters) {
   if (typeof elem === "function") {
     elem.isFunction = true;
-    // Changed the function calling to use apply with the current context to make sure 
+    // Changed the function calling to use apply with the current context to make sure
     // that "this" is wat we expect it to be inside the function
     elem = elem.apply(context.current(), [this, context, null, {auto: auto, filters: filters}]);
     if (elem instanceof Chunk) {
@@ -382,7 +386,11 @@ Chunk.prototype.reference = function(elem, context, auto, filters) {
 Chunk.prototype.section = function(elem, context, bodies, params) {
   // anonymous functions
   if (typeof elem === "function") {
-    elem = elem.apply(context.current(), [this, context, bodies, params]);
+    try {
+      elem = elem.apply(context.current(), [this, context, bodies, params]);
+    } catch(e) {
+      return this.setError(e);
+    }
     // functions that return chunks are assumed to have handled the body and/or have modified the chunk
     // use that return value as the current chunk and go to the next method in the chain
     if (elem instanceof Chunk) {
@@ -399,15 +407,15 @@ Chunk.prototype.section = function(elem, context, bodies, params) {
 
   /*
   Dust's default behavior is to enumerate over the array elem, passing each object in the array to the block.
-  When elem resolves to a value or object instead of an array, Dust sets the current context to the value 
+  When elem resolves to a value or object instead of an array, Dust sets the current context to the value
   and renders the block one time.
   */
   //non empty array is truthy, empty array is falsy
   if (dust.isArray(elem)) {
      if (body) {
       var len = elem.length, chunk = this;
       if (len > 0) {
-        // any custom helper can blow up the stack 
+        // any custom helper can blow up the stack
         // and store a flattened context, guard defensively
         if(context.stack.head) {
          context.stack.head['$len'] = len;
@@ -423,15 +431,15 @@ Chunk.prototype.section = function(elem, context, bodies, params) {
          context.stack.head['$len'] = undefined;
         }
         return chunk;
-      } 
+      }
       else if (skip) {
          return skip(this, context);
       }
      }
    }
    // true is truthy but does not change context
    else if (elem  === true) {
-     if (body) { 
+     if (body) {
         return body(this, context);
      }
    }
@@ -445,7 +453,7 @@ Chunk.prototype.section = function(elem, context, bodies, params) {
    // undefined are all falsy
   } else if (skip) {
      return skip(this, context);
-   }  
+   }
   return this;
 };
 
@@ -515,7 +523,11 @@ Chunk.prototype.partial = function(elem, context, params) {
 Chunk.prototype.helper = function(name, context, bodies, params) {
   // handle invalid helpers, similar to invalid filters
   if( dust.helpers[name]){
-   return dust.helpers[name](this, context, bodies, params);
+    try {
+      return dust.helpers[name](this, context, bodies, params);
+    } catch (e) {
+      return this.setError(e);
+    }
   } else {
     return this;
   }

test/jasmine-test/spec/coreTests.js

@@ -1,5 +1,5 @@
 var coreTests = [
-  { 
+  {
     name: "core tests",
     tests: [
       {
@@ -573,7 +573,7 @@ var coreTests = [
       {
         name: "using len in array reference Accessing",
         source: "{#list3}{.[$len].idx}{/list3}",
-        context: { "list3": [ 
+        context: { "list3": [
                     [{"idx": "0"},
                      {"idx": "1"},
                      {"idx": "2"}],
@@ -704,7 +704,7 @@ var coreTests = [
       }
     ]
   },
-  { 
+  {
     name: "partial definitions",
     tests: [
       {
@@ -866,7 +866,7 @@ var coreTests = [
   {
     name: "inline partial/block tests",
     tests: [
-      {  
+      {
         name: "blocks with dynamic keys",
         source: ['{<title_A}',
                     'AAA',
@@ -1215,7 +1215,7 @@ var coreTests = [
         name: "Dust syntax error. Error in Conditional",
         source:["{?tags}",
                   "<ul>{~n}",
-                    "{#tags}{~s}", 
+                    "{#tags}{~s}",
                       "<li>{#@$}</li>{~n}",
                     "{/tags}",
                   "</ul>",
@@ -1230,7 +1230,7 @@ var coreTests = [
         name: "Dust syntax error. Error in Conditional's else",
         source:["{?tags}",
                   "<ul>{~n}",
-                    "{#tags}{~s}", 
+                    "{#tags}{~s}",
                       "<li>{.}</li>{~n}",
                     "{/tags}",
                   "</ul>",
@@ -1246,7 +1246,7 @@ var coreTests = [
         name: "Dust syntax error. Error in Conditional without end tag",
         source:["{?tags}",
                   "<ul>{~n}",
-                    "{#tags}{~s}", 
+                    "{#tags}{~s}",
                       "<li>{.}</li>{~n}",
                     "{/tags}",
                   "</ul>",
@@ -1255,6 +1255,20 @@ var coreTests = [
         context: {},
         error: 'Expected end tag for tags but it was not found. At line : 8, column : 9',
         message: "should test the errors message for Conditional without end tag."
+      },
+      {
+        name: "Helper syntax error. TypeError",
+        source:"{#hello/}",
+        context: {"hello":function() { var a; a.slice(1); }},
+        error: "Cannot call method 'slice' of undefined",
+        message: "should test helper syntax errors being handled gracefully"
+      },
+      {
+        name: "Helper syntax error. async TypeError",
+        source:"{#hello/}",
+        context: {"hello":function(chunk, context, bodies, params) { return chunk.map(function(chunk) { var a; a.slice(1); chunk.end(); })}},
+        error: "Cannot call method 'slice' of undefined",
+        message: "should test helper syntax errors inside an async block being handled gracefully"
       }
     ]
   },

test/jasmine-test/spec/renderTestSpec.js

@@ -14,7 +14,7 @@ function render(test) {
     try {
       dust.loadSource(dust.compile(test.source, test.name, test.strip));
       dust.render(test.name, test.context, function(err, output) {
-        expect(err).toBeNull();
+        if(err) throw err;
         expect(test.expected).toEqual(output);
       });
     }
@@ -41,17 +41,18 @@ function stream(test) {
         })
         .on("error", function(err) {
           output = err.message;
+          flag = true;
         });
       } catch(error) {
         output = error.message;
-        flag= true;
+        flag = true;
       }
     });
-    
+
     waitsFor(function(){
       return flag;
     }, "the output", 500);
-    
+
     runs(function(){
       if (test.error) {
         expect(test.error || {} ).toEqual(output);
@@ -105,11 +106,11 @@ function pipe(test) {
         flagTwo= true;
       }
     });
-    
+
     waitsFor(function(){
       return flag && flagTwo;
     }, "the output", 500);
-    
+
     runs(function(){
       if (test.error) {
         expect(test.error || {} ).toEqual(output);