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NIFI-16069 - PutIcebergRecord fails with ClassCastException when writing complex types (arrays, maps, nested records) #11391

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NIFI-16069 - PutIcebergRecord fails with ClassCastException when writing complex types (arrays, maps, nested records) #11391

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3d834a3
NIFI-16069 - PutIcebergRecord fails with ClassCastException when writ…
maltesander Jul 2, 2026
d174fd3
refactor: extract nested complex conditionals to convertComplexValue …
maltesander Jul 10, 2026
ef3e162
tests: use static constants for field names and values
maltesander Jul 10, 2026
c9b79b4
Merge remote-tracking branch 'origin/main' into NIFI-16069
maltesander Jul 14, 2026
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57 changes: 57 additions & 0 deletions ...iter/src/test/java/org/apache/nifi/services/iceberg/parquet/ParquetIcebergWriterTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,8 @@
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.util.List;
import java.util.Map;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertInstanceOf;
Expand Down Expand Up @@ -76,6 +78,24 @@ class ParquetIcebergWriterTest {
LocalDate.ofEpochDay(1), LocalTime.ofSecondOfDay(0)
);

private static final String ID_FIELD_NAME = "id";

private static final String TAGS_FIELD_NAME = "tags";

private static final String ADDRESS_FIELD_NAME = "address";

private static final String CITY_FIELD_NAME = "city";

private static final String ATTRIBUTES_FIELD_NAME = "attributes";

private static final String ID_FIELD_VALUE = "row-1";

private static final String CITY_FIELD_VALUE = "Berlin";

private static final List<String> TAGS_FIELD_VALUE = List.of("a", "b");

private static final Map<String, String> ATTRIBUTES_FIELD_VALUE = Map.of("k", "v");

private ParquetIcebergWriter parquetIcebergWriter;

private TestRunner runner;
Expand Down Expand Up @@ -194,6 +214,43 @@ void testWriteDataFilesPartitionedTimestamp() throws IOException {
assertEquals(microsecondsExpected, partitionField);
}

@Test
void testWriteDataFilesComplexTypes() throws IOException {
runner.enableControllerService(parquetIcebergWriter);

final Types.StructType nestedStruct = Types.StructType.of(
Types.NestedField.optional(10, CITY_FIELD_NAME, Types.StringType.get())
);
final Schema schema = new Schema(
Types.NestedField.required(1, ID_FIELD_NAME, Types.StringType.get()),
Types.NestedField.optional(2, TAGS_FIELD_NAME,
Types.ListType.ofOptional(3, Types.StringType.get())),
Types.NestedField.optional(4, ADDRESS_FIELD_NAME, nestedStruct),
Types.NestedField.optional(5, ATTRIBUTES_FIELD_NAME,
Types.MapType.ofOptional(6, 7, Types.StringType.get(), Types.StringType.get()))
);
Comment on lines +224 to +231

@exceptionfactory exceptionfactory Jul 10, 2026

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The field names should be declared statically and reused in both the input Schema and output row.

@maltesander maltesander Jul 11, 2026

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Moved hardcoded constants to static ones: ef3e162

final InMemoryOutputFile outputFile = new InMemoryOutputFile();
final PartitionSpec partitionSpec = PartitionSpec.unpartitioned();
setTable(schema, partitionSpec, outputFile);
when(locationProvider.newDataLocation(anyString())).thenReturn(LOCATION);

final IcebergRowWriter rowWriter = parquetIcebergWriter.getRowWriter(table);

final GenericRecord address = GenericRecord.create(nestedStruct);
address.setField(CITY_FIELD_NAME, CITY_FIELD_VALUE);

final GenericRecord row = GenericRecord.create(schema);
row.setField(ID_FIELD_NAME, ID_FIELD_VALUE);
row.setField(TAGS_FIELD_NAME, TAGS_FIELD_VALUE);
row.setField(ADDRESS_FIELD_NAME, address);
row.setField(ATTRIBUTES_FIELD_NAME, ATTRIBUTES_FIELD_VALUE);
rowWriter.write(row);

final DataFile[] dataFiles = rowWriter.dataFiles();
final byte[] serialized = outputFile.toByteArray();
assertDataFilesFound(dataFiles, serialized);
}

private void writeRow(final Schema schema, final IcebergRowWriter rowWriter) throws IOException {
final GenericRecord row = GenericRecord.create(schema);
row.setField(FIRST_FIELD_NAME, FIRST_FIELD_VALUE);
Expand Down
2 changes: 1 addition & 1 deletion ...g-processors/src/main/java/org/apache/nifi/processors/iceberg/record/DelegatedRecord.java
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Expand Up @@ -38,8 +38,8 @@ public DelegatedRecord(
final org.apache.nifi.serialization.record.Record record,
final Types.StructType struct
) {
this.record = RecordConverter.getConvertedRecord(Objects.requireNonNull(record));
this.struct = Objects.requireNonNull(struct);
this.record = RecordConverter.getConvertedRecord(Objects.requireNonNull(record), struct);
}

@Override
Expand Down
102 changes: 75 additions & 27 deletions ...g-processors/src/main/java/org/apache/nifi/processors/iceberg/record/RecordConverter.java
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,8 @@
*/
package org.apache.nifi.processors.iceberg.record;

import org.apache.nifi.serialization.record.DataType;
import org.apache.iceberg.types.Type;
import org.apache.iceberg.types.Types;
import org.apache.nifi.serialization.record.MapRecord;
import org.apache.nifi.serialization.record.Record;
import org.apache.nifi.serialization.record.RecordField;
Expand All @@ -26,6 +27,9 @@
import java.sql.Date;
import java.sql.Time;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
Expand All @@ -39,63 +43,107 @@ class RecordConverter {
private static final Set<RecordFieldType> CONVERSION_REQUIRED_FIELD_TYPES = Set.of(
RecordFieldType.TIMESTAMP,
RecordFieldType.DATE,
RecordFieldType.TIME
RecordFieldType.TIME,
RecordFieldType.ARRAY,
RecordFieldType.RECORD,
RecordFieldType.MAP
);

/**
* Get Converted Record with conditional handling for field values requiring translation
* Get Converted Record with recursive, schema-aware handling for field values requiring translation
*
* @param inputRecord Input Record to be converted
* @param struct Iceberg Struct Type describing the target field types (may be null for scalar-only conversion)
* @return Input Record or new Record with converted field values
*/
static Record getConvertedRecord(final Record inputRecord) {
final Record convertedRecord;

static Record getConvertedRecord(final Record inputRecord, final Types.StructType struct) {
final RecordSchema recordSchema = inputRecord.getSchema();
if (isConversionRequired(recordSchema)) {
final Map<String, Object> values = inputRecord.toMap();
convertedRecord = getConvertedRecord(recordSchema, values);
} else {
convertedRecord = inputRecord;
if (!isConversionRequired(recordSchema)) {
return inputRecord;
}

return convertedRecord;
}

private static Record getConvertedRecord(final RecordSchema recordSchema, final Map<String, Object> values) {
final Map<String, Object> values = inputRecord.toMap();
final Map<String, Object> convertedValues = new LinkedHashMap<>();

for (final Map.Entry<String, Object> entry : values.entrySet()) {
final String field = entry.getKey();
final Object value = entry.getValue();
final Object converted = getConvertedValue(value);
convertedValues.put(field, converted);
final Type fieldType = fieldType(struct, field);
convertedValues.put(field, convertValue(entry.getValue(), fieldType));
}

return new MapRecord(recordSchema, convertedValues);
}

private static Object getConvertedValue(final Object value) {
static Object convertValue(final Object value, final Type icebergType) {
return switch (value) {
// Convert java.sql types to corresponding java.time types for Apache Iceberg
case Timestamp timestamp -> timestamp.toLocalDateTime();
case Date date -> date.toLocalDate();
case Time time -> time.toLocalTime();
case null, default -> value;
// Recursively convert complex types against the matching Iceberg type
case null, default -> convertComplexValue(value, icebergType);
};
}

private static boolean isConversionRequired(final RecordSchema recordSchema) {
final List<RecordField> fields = recordSchema.getFields();
/**
* Recursively convert array, collection, nested record, and map values against the matching Iceberg type.
* The value is returned unchanged when the target Iceberg type is unknown or does not describe a complex type
* matching the value.
*/
private static Object convertComplexValue(final Object value, final Type icebergType) {
if (icebergType == null) {
return value;
}

if (icebergType.isListType()) {
final Type elementType = icebergType.asListType().elementType();
if (value instanceof Object[] array) {
return convertList(Arrays.asList(array), elementType);
}
if (value instanceof Collection<?> collection) {
return convertList(collection, elementType);
}
} else if (icebergType.isStructType() && value instanceof Record nestedRecord) {
return new DelegatedRecord(nestedRecord, icebergType.asStructType());
} else if (icebergType.isMapType() && value instanceof Map<?, ?> map) {
return convertMap(map, icebergType.asMapType());
}

for (final RecordField field : fields) {
final DataType dataType = field.getDataType();
final RecordFieldType recordFieldType = dataType.getFieldType();
return value;
}

private static List<Object> convertList(final Collection<?> collection, final Type elementType) {
final List<Object> converted = new ArrayList<>(collection.size());
for (final Object element : collection) {
converted.add(convertValue(element, elementType));
}
return converted;
}

private static Map<Object, Object> convertMap(final Map<?, ?> map, final Types.MapType mapType) {
final Map<Object, Object> converted = new LinkedHashMap<>();

@maltesander maltesander Jul 11, 2026

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LinkedHashMap vs HashMap might be debateable?

for (final Map.Entry<?, ?> entry : map.entrySet()) {
final Object key = convertValue(entry.getKey(), mapType.keyType());
final Object mappedValue = convertValue(entry.getValue(), mapType.valueType());
converted.put(key, mappedValue);
}
return converted;
}

private static Type fieldType(final Types.StructType struct, final String fieldName) {
if (struct == null) {
return null;
}
final Types.NestedField nestedField = struct.field(fieldName);
return nestedField == null ? null : nestedField.type();
}

private static boolean isConversionRequired(final RecordSchema recordSchema) {
for (final RecordField field : recordSchema.getFields()) {
final RecordFieldType recordFieldType = field.getDataType().getFieldType();
if (CONVERSION_REQUIRED_FIELD_TYPES.contains(recordFieldType)) {
return true;
}
}

return false;
}
}
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