Blink-in-JS: Output a correct JS file name and line number when an exception is thrown

Source/bindings/core/v8/PrivateScriptRunner.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "bindings/core/v8/PrivateScriptRunner.h"
 
 #include "bindings/core/v8/DOMWrapperWorld.h"
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/V8Binding.h"
 #include "bindings/core/v8/V8PerContextData.h"
 #include "bindings/core/v8/V8ScriptRunner.h"
 #include "core/PrivateScriptSources.h"
 #ifndef NDEBUG
 #include "core/PrivateScriptSourcesForTesting.h"
 #endif
 #include "core/dom/ExceptionCode.h"
 
 namespace blink {
 
 static void dumpV8Message(v8::Handle<v8::Message> message)
 {
     if (message.IsEmpty())
         return;
 
-    // FIXME: How can we get a resource name when an exception is thrown by DOM attributes/methods
-    // implemented in private scripts? In that case, currently ResourceName() returns an empty handle.
+    // FIXME: GetScriptOrigin() and GetLineNumber() return empty handles
+    // when they are called at the first time if V8 has a pending exception.
+    // So we need to call twice to get a correct ScriptOrigin and line number.
+    // This is a bug of V8.

[Jens Widell, 2014/08/15 04:55:29]

Is there a bug report?

[haraken, 2014/08/15 04:57:23]

Not yet, I'm writing a fix :)

+    message->GetScriptOrigin();
+    message->GetLineNumber();
+
     v8::Handle<v8::Value> resourceName = message->GetScriptOrigin().ResourceName();
     String fileName = "Unknown JavaScript file";
     if (!resourceName.IsEmpty() && resourceName->IsString())
         fileName = toCoreString(v8::Handle<v8::String>::Cast(resourceName));
     int lineNumber = message->GetLineNumber();
     v8::Handle<v8::String> errorMessage = message->Get();
     fprintf(stderr, "%s (line %d): %s\n", fileName.utf8().data(), lineNumber, toCoreString(errorMessage).utf8().data());
 }
 
 static void dumpJSError(String exceptionName, v8::Handle<v8::Message> message)
@@ skipping 248 matching lines @@
     if (exceptionName == "ReferenceError") {
         exceptionState.throwDOMException(V8ReferenceError, messageString);
         exceptionState.throwIfNeeded();
         dumpJSError(exceptionName, tryCatchMessage);
         return true;
     }
     return false;
 }
 
 } // namespace blink