branch-4.0: [bug](iceberg) mapping iceberg varint type to unsupported type #64331

docker/thirdparties/docker-compose/iceberg/scripts/create_preinstalled_scripts/iceberg/run30.sql

@@ -0,0 +1,11 @@
+create database if not exists demo.test_db;
+use demo.test_db;
+CREATE TABLE test_variant_repro (
+    id INT,
+    v VARIANT
+)
+USING iceberg
+TBLPROPERTIES (
+    'format-version' = '3',
+    'write.format.default' = 'parquet'
+);

fe/fe-core/src/main/java/org/apache/doris/datasource/iceberg/IcebergUtils.java

@@ -622,6 +622,8 @@ public static Type icebergTypeToDorisType(org.apache.iceberg.types.Type type, bo
                                 icebergTypeToDorisType(x.type(), enableMappingVarbinary, enableMappingTimestampTz)))
                         .collect(Collectors.toCollection(ArrayList::new));
                 return new StructType(nestedTypes);
+            case VARIANT:
+                return Type.UNSUPPORTED;
             default:
                 throw new IllegalArgumentException("Cannot transform unknown type: " + type);
         }

regression-test/suites/external_table_p0/iceberg/test_iceberg_varbinary.groovy

@@ -161,4 +161,15 @@ suite("test_iceberg_varbinary", "p0,external,doris,external_docker,external_dock
     qt_select23 """
         select * from binary_partitioned_table where from_hex(partition_bin)="0FF102FDFEFF";
     """
+
+    sql """ use test_db; """
+    qt_select23 """
+        select id from test_variant_repro;
+    """
+    test {
+        sql """
+            select * from test_variant_repro;
+        """
+        exception "UNSUPPORTED"
+    }
 }