unexpected behavior of NULL_STRATEGY.SKIP indexing null values

[erickj]

ArcadeDB Version: 22.9.1

JDK Version: openjdk 11

OS: Linux jupiter 5.19.9-200.fc36.x86_64 #1 SMP PREEMPT_DYNAMIC Thu Sep 15 09:49:52 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux

Expected behavior

Null property values not to be indexed when defining the index with NULL_STRATEGY.SKIP

Actual behavior

the first document in the index with a null property value gets indexed, then future document insertions with a null property value fail with DuplicatedKeyException. see stacktrace in the gist

Steps to reproduce

see https://gist.github.com/erickj/d982096c5eee4f0f5311d16cdb56b525

If this is just my own misunderstanding of the NULL_STRATEGY.SKIP behavior I'm happy to update the documentation with the expected behavior. Otherwise I'm happy to work on a PR,

[lvca]

Reproduced, thanks for the test case.

[lvca]

The issue relies on a check that is not necessary in the case the value is NULL and the NULL STRATEGY is SKIP. This should also speed up operation for this specific use case. Fixed in the main branch and will be released with this month's version (22.10.1)