All of those are related to semantics where length returns 1 for invalid character, so scans can advance while consuming arrays (were we have -1 and fall into infinite loops or AIOOBE)
Ultimately, we need to decide whether to scatter our code with more costly validating length routines (which would be wasteful for already validated Strings), or try a less wasteful approach by expanding on https://github.com/jruby/jcodings/tree/unsafe-encoding
MRI has several character length routines that have different semantics and are used quite inconsistently, wiki: https://github.com/jruby/jruby/wiki/Encodings-in-JRuby.
For now we only have two semantics:
There are several issues: https://github.com/jruby/jcodings/issues/25 https://github.com/jruby/joni/issues/38 https://github.com/jruby/joni/issues/17 https://github.com/jruby/joni/issues/46
All of those are related to semantics where length returns 1 for invalid character, so scans can advance while consuming arrays (were we have -1 and fall into infinite loops or AIOOBE)
Presto mitigated some of that by using our NonStrictUtf8Encoding here: https://github.com/prestodb/presto/issues/8711
Ultimately, we need to decide whether to scatter our code with more costly validating length routines (which would be wasteful for already validated Strings), or try a less wasteful approach by expanding on https://github.com/jruby/jcodings/tree/unsafe-encoding