Down integrate to GitHub

Author: Hao Nguyen

java/core/src/main/java/com/google/protobuf/AbstractMessage.java

@@ -108,7 +108,7 @@ public FieldDescriptor getOneofFieldDescriptor(OneofDescriptor oneof) {
 
   @Override
   public final String toString() {
-    return TextFormat.printToString(this);
+    return TextFormat.printer().printToString(this);
   }
 
   @Override
@@ -468,7 +468,7 @@ public Message.Builder getRepeatedFieldBuilder(final FieldDescriptor field, int
 
     @Override
     public String toString() {
-      return TextFormat.printToString(this);
+      return TextFormat.printer().printToString(this);
     }
 
     /** Construct an UninitializedMessageException reporting missing fields in the given message. */

java/core/src/main/java/com/google/protobuf/ExtensionRegistryLite.java

@@ -76,6 +76,10 @@ public class ExtensionRegistryLite {
   // applications. Need to support this feature on smaller granularity.
   private static volatile boolean eagerlyParseMessageSets = false;
 
+  // short circuit the ExtensionRegistryFactory via assumevalues trickery
+  @SuppressWarnings("JavaOptionalSuggestions")
+  private static boolean doFullRuntimeInheritanceCheck = true;
+
   // Visible for testing.
   static final String EXTENSION_CLASS_NAME = "com.google.protobuf.Extension";
 
@@ -107,7 +111,9 @@ public static void setEagerlyParseMessageSets(boolean isEagerlyParse) {
    * available.
    */
   public static ExtensionRegistryLite newInstance() {
-    return ExtensionRegistryFactory.create();
+    return doFullRuntimeInheritanceCheck
+        ? ExtensionRegistryFactory.create()
+        : new ExtensionRegistryLite();
   }
 
   private static volatile ExtensionRegistryLite emptyRegistry;
@@ -122,7 +128,11 @@ public static ExtensionRegistryLite getEmptyRegistry() {
       synchronized (ExtensionRegistryLite.class) {
         result = emptyRegistry;
         if (result == null) {
-          result = emptyRegistry = ExtensionRegistryFactory.createEmpty();
+          result =
+              emptyRegistry =
+                  doFullRuntimeInheritanceCheck
+                      ? ExtensionRegistryFactory.createEmpty()
+                      : EMPTY_REGISTRY_LITE;
         }
       }
     }
@@ -163,7 +173,7 @@ public final void add(ExtensionLite<?, ?> extension) {
     if (GeneratedMessageLite.GeneratedExtension.class.isAssignableFrom(extension.getClass())) {
       add((GeneratedMessageLite.GeneratedExtension<?, ?>) extension);
     }
-    if (ExtensionRegistryFactory.isFullRegistry(this)) {
+    if (doFullRuntimeInheritanceCheck && ExtensionRegistryFactory.isFullRegistry(this)) {
       try {
         this.getClass().getMethod("add", extensionClass).invoke(this, extension);
       } catch (Exception e) {

java/core/src/main/java/com/google/protobuf/Message.java

@@ -85,7 +85,7 @@ public interface Message extends MessageLite, MessageOrBuilder {
 
   /**
    * Converts the message to a string in protocol buffer text format. This is just a trivial wrapper
-   * around {@link TextFormat#printToString(MessageOrBuilder)}.
+   * around {@link TextFormat.Printer#printToString(MessageOrBuilder)}.
    */
   @Override
   String toString();