Ensure BasicDBObject equals/hashCode works with UUID values (#688)

JAVA-4051

Author: jyemin

driver-core/src/main/com/mongodb/BasicDBObject.java

@@ -21,12 +21,14 @@
 import org.bson.BsonBinaryWriter;
 import org.bson.BsonDocument;
 import org.bson.BsonDocumentWrapper;
+import org.bson.UuidRepresentation;
 import org.bson.codecs.Decoder;
 import org.bson.codecs.DecoderContext;
 import org.bson.codecs.Encoder;
 import org.bson.codecs.EncoderContext;
 import org.bson.codecs.configuration.CodecRegistry;
 import org.bson.conversions.Bson;
+import org.bson.internal.CodecRegistryHelper;
 import org.bson.io.BasicOutputBuffer;
 import org.bson.io.OutputBuffer;
 import org.bson.json.JsonMode;
@@ -220,10 +222,15 @@ public int hashCode() {
         return Arrays.hashCode(toBson(canonicalizeBSONObject(this)));
     }
 
+    /**
+     * Convert the object to its BSON representation, using the {@code STANDARD} representation for UUID.  This is safe to do in the context
+     * of this class because currently this method is only used for equality and hash code, and is not passed to any other parts of the
+     * library.
+     */
     private static byte[] toBson(final DBObject dbObject) {
         OutputBuffer outputBuffer = new BasicOutputBuffer();
-        DBObjectCodec.getDefaultRegistry().get(DBObject.class).encode(new BsonBinaryWriter(outputBuffer), dbObject,
-                EncoderContext.builder().build());
+        CodecRegistryHelper.createRegistry(DBObjectCodec.getDefaultRegistry(), UuidRepresentation.STANDARD)
+                .get(DBObject.class).encode(new BsonBinaryWriter(outputBuffer), dbObject, EncoderContext.builder().build());
         return outputBuffer.toByteArray();
     }
 

driver-core/src/test/unit/com/mongodb/BasicDBObjectTest.java

@@ -30,6 +30,7 @@
 import java.util.HashMap;
 import java.util.Map;
 import java.util.TreeMap;
+import java.util.UUID;
 
 import static java.util.Arrays.asList;
 import static org.hamcrest.CoreMatchers.not;
@@ -218,6 +219,15 @@ public void testEqualsAndHashCode() {
         assertEquality(new BasicDBObject("a", first), new BasicBSONObject("a", third));
     }
 
+    @Test
+    public void testUuid() {
+        UUID uuid = UUID.randomUUID();
+        BasicDBObject dbo1 = new BasicDBObject("_id", uuid);
+        BasicDBObject dbo2 = new BasicDBObject("_id", uuid);
+
+        assertEquality(dbo1, dbo2);
+    }
+
     void assertEquality(final BSONObject x, final BSONObject y) {
         assertEquals(x, y);
         assertEquals(y, x);