JAVA-3057 Allow decoding a UDT that has more fields than expected

Author: akhaku

core/src/main/java/com/datastax/oss/driver/internal/core/type/codec/UdtCodec.java

@@ -30,10 +30,14 @@
 import java.nio.BufferUnderflowException;
 import java.nio.ByteBuffer;
 import net.jcip.annotations.ThreadSafe;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 @ThreadSafe
 public class UdtCodec implements TypeCodec<UdtValue> {
 
+  private static final Logger LOG = LoggerFactory.getLogger(UdtCodec.class);
+
   private final UserDefinedType cqlType;
 
   public UdtCodec(@NonNull UserDefinedType cqlType) {
@@ -107,10 +111,8 @@ public UdtValue decode(@Nullable ByteBuffer bytes, @NonNull ProtocolVersion prot
       int i = 0;
       while (input.hasRemaining()) {
         if (i == cqlType.getFieldTypes().size()) {
-          throw new IllegalArgumentException(
-              String.format(
-                  "Too many fields in encoded UDT value, expected %d",
-                  cqlType.getFieldTypes().size()));
+          LOG.debug("Encountered unexpected fields when parsing codec {}", cqlType);
+          break;
         }
         int elementSize = input.getInt();
         ByteBuffer element;

core/src/test/java/com/datastax/oss/driver/internal/core/type/codec/UdtCodecTest.java

@@ -136,18 +136,18 @@ public void should_decode_udt() {
   }
 
   @Test
-  public void should_fail_to_decode_udt_when_too_many_fields() {
-    assertThatThrownBy(
-            () ->
-                decode(
-                    "0x"
-                        + ("00000004" + "00000001")
-                        + "ffffffff"
-                        + ("00000001" + "61")
-                        // extra contents
-                        + "ffffffff"))
-        .isInstanceOf(IllegalArgumentException.class)
-        .hasMessage("Too many fields in encoded UDT value, expected 3");
+  public void should_decode_udt_when_too_many_fields() {
+    UdtValue udt =
+        decode(
+            "0x"
+                + ("00000004" + "00000001")
+                + "ffffffff"
+                + ("00000001" + "61")
+                // extra contents
+                + "ffffffff");
+    assertThat(udt.getInt(0)).isEqualTo(1);
+    assertThat(udt.isNull(1)).isTrue();
+    assertThat(udt.getString(2)).isEqualTo("a");
   }
 
   /** Test for JAVA-2557. Ensures that the codec can decode null fields with any negative length. */