properly report source:line:column on SyntaxErrors.

ext/v8/v8_msg.cpp

@@ -24,7 +24,8 @@ namespace {
   }
 
   VALUE GetStackTrace(VALUE self) {
-    return rr_v82rb(unwrap(self)->GetStackTrace());
+    Handle<StackTrace> trace = unwrap(self)->GetStackTrace();
+    return trace.IsEmpty() ? Qnil : rr_v82rb(trace);
   }
 
   VALUE GetLineNumber(VALUE self) {

lib/v8/error.rb

@@ -41,7 +41,6 @@ module V8
       else
         @value = ex
         message = ex.to_s
-        @boundaries.first.jsframes << 'at [???].js'
       end
       return message
     end
@@ -88,13 +87,31 @@ module V8
     end
 
     def parse_js_frames(try)
+      #I can't figure out why V8 is not capturing the stacktrace here
+      #in terms of StackTrace and StackFrame objects, so we have to
+      #parse the string.
       raw = @to.rb(try.StackTrace())
-      if raw && !raw.empty?
+      if raw && !raw.empty? && !syntax_error?(try)
         raw.split("\n")[1..-1].tap do |frames|
           frames.each {|frame| frame.strip!.chomp!(",")}
         end
       else
-        []
+        msg = try.Message()
+        ["at #{@to.rb(msg.GetScriptResourceName())}:#{msg.GetLineNumber()}:#{msg.GetStartColumn() + 1}"]
+      end
+    end
+
+    #Syntax errors are weird in that they have a non-empty stack trace
+    #but it does not contain any source location information, so
+    #in these instances, we have to pull it out of the Message object
+    #in the TryCatch. Is there a better way to detect a syntax error
+    def syntax_error?(try)
+      ex = try.Exception()
+      if ex && ex.kind_of?(V8::C::Object)
+        type = ex.Get("constructor")
+        type && type.kind_of?(V8::C::Function) && type.GetName().AsciiValue == "SyntaxError"
+      else
+        false
       end
     end
 

spec/v8/error_spec.rb

@@ -1,7 +1,7 @@
 require File.expand_path(File.dirname(__FILE__) + '/../spec_helper')
 
 describe V8::JSError do
-  
+
   before(:each) do
     @cxt = V8::Context.new
     @cxt['one'] = lambda do
@@ -11,13 +11,13 @@ describe V8::JSError do
       @cxt.eval('three()', 'two.js')
     end
   end
-  
+
   it "captures a message without over nesting when the error is an error" do
     throw! do |e|
       e.message.should == "BOOM!"
     end
   end
-  
+
   it "captures the js message without over nesting when the error is a normal object" do
     throw!('{foo: "bar"}') do |e|
       e.message.should == "[object Object]"
@@ -26,7 +26,7 @@ describe V8::JSError do
       e.message.should == "bar"
     end
   end
-  
+
   it "captures a thrown value as the message" do
     throw!('"BOOM!"') do |e|
       e.message.should == "BOOM!"
@@ -35,7 +35,7 @@ describe V8::JSError do
       e.message.should == '6'
     end
   end
-  
+
   it "has a reference to the root javascript cause" do
     throw!('"I am a String"') do |e|
       e.should_not be_in_ruby
@@ -43,7 +43,7 @@ describe V8::JSError do
       e.value.should == "I am a String"
     end
   end
-  
+
   it "has a reference to the root ruby cause if one exists" do
     StandardError.new("BOOM!").tap do |bomb|
       @cxt['boom'] = lambda do
@@ -58,9 +58,9 @@ describe V8::JSError do
       end)
     end
   end
-  
+
   describe "backtrace" do
-    
+
     it "is mixed with ruby and javascript" do
       throw! do |e|
         e.backtrace.first.should == "at three.js:1:7"
@@ -89,10 +89,23 @@ describe V8::JSError do
     
     it "includes a mystery marker when the original frame is unavailable because what got thrown wasn't an error" do
       throw!("6") do |e|
-        e.backtrace.first.should == 'at [???].js'
+        e.backtrace.first.should == 'at three.js:1:1'
       end
     end
     
+    it "has a source name and line number when there is a javascript SyntaxError" do
+      lambda do
+        @cxt.eval(<<-INVALID, 'source.js')
+"this line is okay";
+"this line has a syntax error because it ends with a colon":
+"this line is also okay";
+"how do I find out that line 2 has the syntax error?";
+INVALID
+      end.should raise_error(V8::JSError) {|error|
+        error.backtrace.first.should == 'at source.js:2:60'
+      }
+    end
+
     it "can start with ruby at the bottom" do
       @cxt['boom'] = lambda do
         raise StandardError, "Bif!"