prestodb/presto · error · IllegalArgumentException

A null array must have zero entries

Error message

A null array must have zero entries

What it means

ArrayBlock.fromElementBlock validation: a position whose valueIsNull entry is true must encode an empty array (offsets equal), but the given offsets/values describe a non-empty null array — inconsistent block construction arguments.

Source

Thrown at presto-common/src/main/java/com/facebook/presto/common/block/ArrayBlock.java:60

    private volatile long logicalSizeInBytes;

    /**
     * Create an array block directly from columnar nulls, values, and offsets into the values.
     * A null array must have no entries.
     */
    public static Block fromElementBlock(int positionCount, Optional<boolean[]> valueIsNullOptional, int[] arrayOffset, Block values)
    {
        boolean[] valueIsNull = valueIsNullOptional.orElse(null);
        validateConstructorArguments(0, positionCount, valueIsNull, arrayOffset, values);
        // for performance reasons per element checks are only performed on the public construction
        for (int i = 0; i < positionCount; i++) {
            int offset = arrayOffset[i];
            int length = arrayOffset[i + 1] - offset;
            if (length < 0) {
                throw new IllegalArgumentException(format("Offset is not monotonically ascending. offsets[%s]=%s, offsets[%s]=%s", i, arrayOffset[i], i + 1, arrayOffset[i + 1]));
            }
            if (valueIsNull != null && valueIsNull[i] && length != 0) {
                throw new IllegalArgumentException("A null array must have zero entries");
            }
        }
        return new ArrayBlock(0, positionCount, valueIsNull, arrayOffset, values);
    }

    /**
     * Create an array block directly without per element validations.
     */
    static ArrayBlock createArrayBlockInternal(int arrayOffset, int positionCount, @Nullable boolean[] valueIsNull, int[] offsets, Block values)
    {
        validateConstructorArguments(arrayOffset, positionCount, valueIsNull, offsets, values);
        return new ArrayBlock(arrayOffset, positionCount, valueIsNull, offsets, values);
    }

    private static void validateConstructorArguments(int arrayOffset, int positionCount, @Nullable boolean[] valueIsNull, int[] offsets, Block values)
    {
        if (arrayOffset < 0) {
            throw new IllegalArgumentException("arrayOffset is negative");

View on GitHub (pinned to 55bb57d202)

Solutions

1. Emit equal start/end offsets for null array positions in the producer
2. Verify null handling in the block builder or deserializer that produced these arrays

When it happens

Trigger: Thrown at presto-common/src/main/java/com/facebook/presto/common/block/ArrayBlock.java:60 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of prestodb/presto@55bb57d202 (2026-09-04). Data as JSON: /api/errors/81dfa6707bc1cbc3. Report an issue: GitHub.