apache/iceberg · error · java.lang.UnsupportedOperationException

Failed to read Variant %s of type %s as int

Error message

Failed to read Variant %s of type %s as int

What it means

intValue extracts an int from a Variant only when its Variant.Type is TINYINT, SMALLINT, or INT; any other physical type (e.g. BIGINT, DOUBLE, STRING) throws this UnsupportedOperationException via errMsg(variant, "int").

Source

Thrown at flink/v2.1/flink/src/main/java/org/apache/iceberg/flink/data/VariantRowDataWrapper.java:255

    }

    int arraySize = BinaryVariantAccessorUtils.arraySize(variant);
    Object[] elements = new Object[arraySize];

    for (int i = 0; i < arraySize; i++) {
      Variant element = variant.getElement(i);
      elements[i] = elementValue(element, innerElementType);
    }

    return new GenericArrayData(elements);
  }

  private static int intValue(Variant variant) {
    return switch (variant.getType()) {
      case TINYINT -> variant.getByte();
      case SMALLINT -> variant.getShort();
      case INT -> variant.getInt();
      default -> throw new UnsupportedOperationException(errMsg(variant, "int"));
    };
  }

  private static long longValue(Variant variant) {
    return switch (variant.getType()) {
      case TINYINT -> variant.getByte();
      case SMALLINT -> variant.getShort();
      case INT -> variant.getInt();
      case BIGINT -> variant.getLong();
      default -> throw new UnsupportedOperationException(errMsg(variant, "long"));
    };
  }

  private static double doubleValue(Variant variant) {
    return switch (variant.getType()) {
      case FLOAT -> variant.getFloat();
      case DOUBLE -> variant.getDouble();
      default -> throw new UnsupportedOperationException(errMsg(variant, "double"));

View on GitHub (pinned to 86d9c8fc54)

Solutions

  1. Check variant.getType() at the source and ensure the writer emits an int-width value
  2. Align the Flink RowType column to INT (not BIGINT) or read with getLong instead
  3. Coerce the variant upstream (cast the value) before writing it into the variant column

Example fix

// before
row.getInt(3); // variant is BIGINT -> throws
// after
long v = row.getLong(3); // matches BIGINT variant
Defensive patterns

Strategy: try-catch

Validate before calling

if (variant.getType() != Variant.Type.TINYINT
    && variant.getType() != Variant.Type.SMALLINT
    && variant.getType() != Variant.Type.INT) { /* coerce or use getLong */ }

Type guard

boolean isIntWidth(Variant v) {
  return v.getType() == Variant.Type.TINYINT || v.getType() == Variant.Type.SMALLINT
      || v.getType() == Variant.Type.INT;
}

Try / catch

try { int i = row.getInt(pos); }
catch (UnsupportedOperationException e) { long l = row.getLong(pos); int i = (int) l; }

Prevention

When it happens

Trigger: Calling getInt on a VariantRowDataWrapper whose column holds a Variant of an incompatible type, or elementValue widening an int-typed field whose variant is e.g. a long.

Common situations: Schema/variant type mismatch after table evolution (column changed from int to long) or writers producing variants of the wrong physical type.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/26d243d1ffd2ccd2. Report an issue: GitHub.