ValueDeserializer: Make sure that an exception is the legacy path.

src/value-serializer.cc

 // Copyright 2016 the V8 project 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 "src/value-serializer.h"
 
 #include <type_traits>
 
 #include "src/base/logging.h"
 #include "src/conversions.h"
@@ skipping 1831 matching lines @@
         isolate, object, key, &success, LookupIterator::OWN);
     if (!success ||
         JSObject::DefineOwnPropertyIgnoreAttributes(&it, value, NONE)
             .is_null()) {
       return Nothing<bool>();
     }
   }
   return Just(true);
 }
 
+namespace {
+
+// Throws a generic "deserialization failed" exception by default, unless a more
+// specific exception has already been thrown.
+void ThrowDeserializationExceptionIfNonePending(Isolate* isolate) {
+  if (!isolate->has_pending_exception()) {
+    isolate->Throw(*isolate->factory()->NewError(
+        MessageTemplate::kDataCloneDeserializationError));
+  }
+  DCHECK(isolate->has_pending_exception());
+}
+
+}  // namespace
+
 MaybeHandle<Object>
 ValueDeserializer::ReadObjectUsingEntireBufferForLegacyFormat() {
   DCHECK_EQ(version_, 0u);
   HandleScope scope(isolate_);
   std::vector<Handle<Object>> stack;
   while (position_ < end_) {
     SerializationTag tag;
     if (!PeekTag().To(&tag)) break;
 
     Handle<Object> new_object;
@@ skipping 12 matching lines @@
         }
 
         size_t begin_properties =
             stack.size() - 2 * static_cast<size_t>(num_properties);
         Handle<JSObject> js_object = isolate_->factory()->NewJSObject(
             isolate_->object_function(), pretenure_);
         if (num_properties &&
             !SetPropertiesFromKeyValuePairs(
                  isolate_, js_object, &stack[begin_properties], num_properties)
                  .FromMaybe(false)) {
-          DCHECK(isolate_->has_pending_exception());
+          ThrowDeserializationExceptionIfNonePending(isolate_);
           return MaybeHandle<Object>();
         }
 
         stack.resize(begin_properties);
         new_object = js_object;
         break;
       }
       case SerializationTag::kEndSparseJSArray: {
         ConsumeTag(SerializationTag::kEndSparseJSArray);
 
@@ skipping 10 matching lines @@
 
         Handle<JSArray> js_array = isolate_->factory()->NewJSArray(
             0, TERMINAL_FAST_ELEMENTS_KIND, pretenure_);
         JSArray::SetLength(js_array, length);
         size_t begin_properties =
             stack.size() - 2 * static_cast<size_t>(num_properties);
         if (num_properties &&
             !SetPropertiesFromKeyValuePairs(
                  isolate_, js_array, &stack[begin_properties], num_properties)
                  .FromMaybe(false)) {
-          DCHECK(isolate_->has_pending_exception());
+          ThrowDeserializationExceptionIfNonePending(isolate_);
           return MaybeHandle<Object>();
         }
 
         stack.resize(begin_properties);
         new_object = js_array;
         break;
       }
       case SerializationTag::kEndDenseJSArray: {
         // This was already broken in Chromium, and apparently wasn't missed.
         isolate_->Throw(*isolate_->factory()->NewError(
@@ skipping 18 matching lines @@
   if (stack.size() != 1) {
     isolate_->Throw(*isolate_->factory()->NewError(
         MessageTemplate::kDataCloneDeserializationError));
     return MaybeHandle<Object>();
   }
   return scope.CloseAndEscape(stack[0]);
 }
 
 }  // namespace internal
 }  // namespace v8