Fix Symbol decoding in DBObjectCodec

JAVA-1909

Author: rozza

bson/src/main/org/bson/codecs/StringCodec.java

@@ -17,6 +17,7 @@
 package org.bson.codecs;
 
 import org.bson.BsonReader;
+import org.bson.BsonType;
 import org.bson.BsonWriter;
 
 /**
@@ -32,7 +33,11 @@ public void encode(final BsonWriter writer, final String value, final EncoderCon
 
     @Override
     public String decode(final BsonReader reader, final DecoderContext decoderContext) {
-        return reader.readString();
+        if (reader.getCurrentBsonType() == BsonType.SYMBOL) {
+            return reader.readSymbol();
+        } else {
+            return reader.readString();
+        }
     }
 
     @Override

driver/src/test/unit/com/mongodb/DBObjectCodecSpecification.groovy

@@ -23,11 +23,13 @@ import org.bson.BsonBinarySubType
 import org.bson.BsonDocument
 import org.bson.BsonDocumentReader
 import org.bson.BsonDocumentWriter
+import org.bson.BsonSymbol
 import org.bson.codecs.DecoderContext
 import org.bson.codecs.EncoderContext
 import org.bson.codecs.UuidCodec
 import org.bson.codecs.ValueCodecProvider
 import org.bson.types.Binary
+import org.bson.types.Symbol
 import spock.lang.Specification
 
 import static org.bson.UuidRepresentation.STANDARD
@@ -115,4 +117,22 @@ class DBObjectCodecSpecification extends Specification {
         then:
         decodedUuid.get('byteArray') == new Binary(subType, array)
     }
+
+    def 'should encode Symbol to BsonSymbol and decode BsonSymbol to String'() {
+        given:
+        def symbol = new Symbol('symbol');
+        def doc = new BasicDBObject('symbol', symbol)
+
+        when:
+        dbObjectCodec.encode(new BsonDocumentWriter(bsonDoc), doc, EncoderContext.builder().build())
+
+        then:
+        bsonDoc.get('symbol') == new BsonSymbol('symbol')
+
+        when:
+        def decodedSymbol = dbObjectCodec.decode(new BsonDocumentReader(bsonDoc), DecoderContext.builder().build())
+
+        then:
+        decodedSymbol.get('symbol') == symbol.toString()
+    }
 }