Correct handling of exceptions occured during getting of exception stack trace.

src/d8.cc

Index: src/d8.cc
diff --git a/src/d8.cc b/src/d8.cc
index 132891e2b8a694919c0643118dea5fd8ef82b403..2ef7162878713a6c0385c4c5c0ed6a190facb87b 100644
--- a/src/d8.cc
+++ b/src/d8.cc
@@ -587,24 +587,24 @@ Handle<String> Shell::ReadFromStdin(Isolate* isolate) {
 
 
 void Shell::Load(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  Isolate* isolate = args.GetIsolate();
   for (int i = 0; i < args.Length(); i++) {
-    HandleScope handle_scope(args.GetIsolate());
+    HandleScope handle_scope(isolate);
     String::Utf8Value file(args[i]);
     if (*file == NULL) {
-      Throw(args.GetIsolate(), "Error loading file");
+      Throw(isolate, "Error loading file");
       return;
     }
-    Handle<String> source = ReadFile(args.GetIsolate(), *file);
+    Handle<String> source = ReadFile(isolate, *file);
     if (source.IsEmpty()) {
-      Throw(args.GetIsolate(), "Error loading file");
+      Throw(isolate, "Error loading file");
       return;
     }
-    if (!ExecuteString(args.GetIsolate(),
-                       source,
-                       String::NewFromUtf8(args.GetIsolate(), *file),
-                       false,
-                       true)) {
-      Throw(args.GetIsolate(), "Error executing file");
+    if (!ExecuteString(isolate, source, String::NewFromUtf8(isolate, *file),
+                       false, true)) {
+      // Exception is already reported, so clear it before throwing another one.
+      reinterpret_cast<i::Isolate*>(isolate)->clear_pending_exception();

[Yang, 2014/12/23 22:16:09]

Can we assert that there is indeed a pending exception before clearing it?

+      Throw(isolate, "Error executing file");
       return;
     }
   }