ComparisonIndexer is returning a NPE

[mikepictor]

I am getting a NPE from the ComparisonIndexer, not always, but often enough. It happens here..

    public ElementAwareListEntry<T> put(IndexProperties indexProperties, T tuple) {
        Key_ indexKey = indexProperties.toKey(propertyIndex);
        // Avoids computeIfAbsent in order to not create lambdas on the hot path.
        Indexer<T> downstreamIndexer = comparisonMap.get(indexKey);
        if (downstreamIndexer == null) {
            downstreamIndexer = downstreamIndexerSupplier.get();
            comparisonMap.put(indexKey, downstreamIndexer);
        }
        return downstreamIndexer.put(indexProperties, tuple);
    }

In my case, propertyIndex is 2, indexKey is null, indexProperties has 2 elements in it (so the index of 2 points to nothing, thus the null, then on the downstreamIndexer.put it tries to place the tuple with a null key, leading to a NPE from the java Comparators when it compare null to the other keys in the map.

I don't know enough about how this is meant to work, or why the propertyIndex is 2 when there are only properties at index 0 and 1

I can't tell if this is a timefold bug, whether my planning entities are badly formed, or something else.

[mikepictor]

Or indeed, maybe it's my constraint that is causing an issue, though I don't feel they are overly complex constraints.

[triceo]

Hello. Thanks for bringing this to our attention.
Can you please provide a reproducer? Something I can run on my machine to see your problem?
Without that, I'm afraid I can't do much to help.