apache/iceberg · error

Invalid size: + size

Error message

Invalid size: + size

What it means

Thrown by ByteBuffers.writeLittleEndianUnsigned when the size argument is not 1, 2, 3, or 4. The method only knows how to write unsigned little-endian integers of those byte widths into the ByteBuffer.

Solutions

1. Pass only 1, 2, 3, or 4 as size
2. For 8-byte fields use buffer.putLong or a different helper (this method takes an int, so 8 bytes are unsupported)
3. Validate the computed size against allowed widths before writing
4. Check the file-format spec for the actual width of the field being encoded

Example fix

// before
ByteBuffers.writeLittleEndianUnsigned(buf, value, offset, 8);
// after
ByteBuffers.writeLittleEndianUnsigned(buf, value, offset, 4); // int max 4 bytes

if (size < 1 || size > 4) { throw new IllegalArgumentException("writeLittleEndianUnsigned size must be 1-4, got " + size); }

When it happens

Trigger: Calling ByteBuffers.writeLittleEndianUnsigned(buffer, value, offset, size) with size of 0, 5, 8, negative, or any value outside {1,2,3,4}.

Common situations: Code reading/writing binary file formats (e.g. Avro/Parquet metadata, footer structures) where a variable-length encoding bug computes the wrong field width; hardcoded width constants that don't match the field spec.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• Cannot bucket by type:
• AboveMax has no value
• apply(value) is deprecated, use bind(Type).apply(value)
• apply(value) is deprecated, use bind(Type).apply(value)
• Backup table name cannot be specified

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/969b68c63a9ef2ea. Report an issue: GitHub.

Appendix: source

Thrown at api/src/main/java/org/apache/iceberg/util/ByteBuffers.java:100

  public static void writeLittleEndianUnsigned(ByteBuffer buffer, int value, int offset, int size) {
    int base = buffer.position() + offset;
    switch (size) {
      case 4:
        buffer.putInt(base, value);
        return;
      case 3:
        buffer.putShort(base, (short) (value & 0xFFFF));
        buffer.put(base + 2, (byte) ((value >> 16) & 0xFF));
        return;
      case 2:
        buffer.putShort(base, (short) (value & 0xFFFF));
        return;
      case 1:
        buffer.put(base, (byte) (value & 0xFF));
        return;
    }

    throw new IllegalArgumentException("Invalid size: " + size);
  }

  public static byte readLittleEndianInt8(ByteBuffer buffer, int offset) {
    return buffer.get(buffer.position() + offset);
  }

  public static short readLittleEndianInt16(ByteBuffer buffer, int offset) {
    return buffer.getShort(buffer.position() + offset);
  }

  public static int readByte(ByteBuffer buffer, int offset) {
    return buffer.get(buffer.position() + offset) & 0xFF;
  }

  public static int readLittleEndianUnsigned(ByteBuffer buffer, int offset, int size) {
    int base = buffer.position() + offset;
    switch (size) {
      case 4:

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