1 files changed, 34 insertions, 14 deletions

diff --git a/java/core/src/main/java/com/google/protobuf/AbstractMessage.java b/java/core/src/main/java/com/google/protobuf/AbstractMessage.java
index 37180da8..fc3c2a5d 100644
--- a/java/core/src/main/java/com/google/protobuf/AbstractMessage.java
+++ b/java/core/src/main/java/com/google/protobuf/AbstractMessage.java
@@ -32,9 +32,9 @@ package com.google.protobuf;
 
 import com.google.protobuf.Descriptors.EnumValueDescriptor;
 import com.google.protobuf.Descriptors.FieldDescriptor;
+import com.google.protobuf.Descriptors.FileDescriptor.Syntax;
 import com.google.protobuf.Descriptors.OneofDescriptor;
 import com.google.protobuf.Internal.EnumLite;
-
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.Arrays;
@@ -125,6 +125,16 @@ public abstract class AbstractMessage
   protected int memoizedSize = -1;
 
   @Override
+  int getMemoizedSerializedSize() {
+    return memoizedSize;
+  }
+
+  @Override
+  void setMemoizedSerializedSize(int size) {
+    memoizedSize = size;
+  }
+
+  @Override
   public int getSerializedSize() {
     int size = memoizedSize;
     if (size != -1) {
@@ -163,7 +173,7 @@ public abstract class AbstractMessage
     }
     return hash;
   }
-  
+
   private static ByteString toByteString(Object value) {
     if (value instanceof byte[]) {
       return ByteString.copyFrom((byte[]) value);
@@ -171,7 +181,7 @@ public abstract class AbstractMessage
       return (ByteString) value;
     }
   }
- 
+
   /**
    * Compares two bytes fields. The parameters must be either a byte array or a
    * ByteString object. They can be of different type though.
@@ -182,7 +192,7 @@ public abstract class AbstractMessage
     }
     return toByteString(a).equals(toByteString(b));
   }
-  
+
   /**
    * Converts a list of MapEntry messages into a Map used for equals() and
    * hashCode().
@@ -213,7 +223,7 @@ public abstract class AbstractMessage
     }
     return result;
   }
-  
+
   /**
    * Compares two map fields. The parameters must be a list of MapEntry
    * messages.
@@ -224,13 +234,13 @@ public abstract class AbstractMessage
     Map mb = convertMapEntryListToMap((List) b);
     return MapFieldLite.equals(ma, mb);
   }
-  
+
   /**
    * Compares two set of fields.
    * This method is used to implement {@link AbstractMessage#equals(Object)}
    * and {@link AbstractMutableMessage#equals(Object)}. It takes special care
    * of bytes fields because immutable messages and mutable messages use
-   * different Java type to reprensent a bytes field and this method should be
+   * different Java type to represent a bytes field and this method should be
    * able to compare immutable messages, mutable messages and also an immutable
    * message to a mutable message.
    */
@@ -276,7 +286,7 @@ public abstract class AbstractMessage
     }
     return true;
   }
-  
+
   /**
    * Calculates the hash code of a map field. {@code value} must be a list of
    * MapEntry messages.
@@ -328,7 +338,8 @@ public abstract class AbstractMessage
       extends AbstractMessageLite.Builder
       implements Message.Builder {
     // The compiler produces an error if this is not declared explicitly.
-    // Method isn't abstract to bypass Java 1.6 compiler issue http://bugs.java.com/view_bug.do?bug_id=6908259
+    // Method isn't abstract to bypass Java 1.6 compiler issue:
+    //     http://bugs.java.com/view_bug.do?bug_id=6908259
     @Override
     public BuilderType clone() {
       throw new UnsupportedOperationException("clone() should be implemented in subclasses.");
@@ -371,7 +382,7 @@ public abstract class AbstractMessage
     public String getInitializationErrorString() {
       return MessageReflection.delimitWithCommas(findInitializationErrors());
     }
-    
+
     @Override
     protected BuilderType internalMergeFrom(AbstractMessageLite other) {
       return mergeFrom((Message) other);
@@ -379,6 +390,10 @@ public abstract class AbstractMessage
 
     @Override
     public BuilderType mergeFrom(final Message other) {
+      return mergeFrom(other, other.getAllFields());
+    }
+    
+    BuilderType mergeFrom(final Message other, Map<FieldDescriptor, Object> allFields) {
       if (other.getDescriptorForType() != getDescriptorForType()) {
         throw new IllegalArgumentException(
           "mergeFrom(Message) can only merge messages of the same type.");
@@ -393,8 +408,7 @@ public abstract class AbstractMessage
       // TODO(kenton):  Provide a function somewhere called makeDeepCopy()
       //   which allows people to make secure deep copies of messages.
 
-      for (final Map.Entry<FieldDescriptor, Object> entry :
-           other.getAllFields().entrySet()) {
+      for (final Map.Entry<FieldDescriptor, Object> entry : allFields.entrySet()) {
         final FieldDescriptor field = entry.getKey();
         if (field.isRepeated()) {
           for (final Object element : (List)entry.getValue()) {
@@ -432,8 +446,12 @@ public abstract class AbstractMessage
         final CodedInputStream input,
         final ExtensionRegistryLite extensionRegistry)
         throws IOException {
+      boolean discardUnknown =
+          getDescriptorForType().getFile().getSyntax() == Syntax.PROTO3
+              ? input.shouldDiscardUnknownFieldsProto3()
+              : input.shouldDiscardUnknownFields();
       final UnknownFieldSet.Builder unknownFields =
-        UnknownFieldSet.newBuilder(getUnknownFields());
+          discardUnknown ? null : UnknownFieldSet.newBuilder(getUnknownFields());
       while (true) {
         final int tag = input.readTag();
         if (tag == 0) {
@@ -451,7 +469,9 @@ public abstract class AbstractMessage
           break;
         }
       }
-      setUnknownFields(unknownFields.build());
+      if (unknownFields != null) {
+        setUnknownFields(unknownFields.build());
+      }
       return (BuilderType) this;
     }