PostgreSQL has the beginnings of a solution to this problem: version tracking for collations. I think it should be extended to track versions in a more fine gr

PostgreSQL has the beginnings of a solution to this problem: version tracking for collations. I think it should be extended to track versions in a more fine grained way so that it can detect and reject this scenario (and related scenarios), and I think that libc implementations should provide a way to expose the version. I have proposed this for FreeBSD libc, and I hope someone proposes something similar for glibc (maybe me eventually). I think PostgreSQL should continue to support both ICU and libc collations (I don't think it's reasonable for every piece of software to use its own collation system, or for everyone to switch to ICU, I think libc should do a slightly better job). More recent discussion of various possible approaches on PostgreSQL -hackers list: https://www.postgresql.org/message-id/flat/CAEepm%3D0uEQCpfq_%2BLYFBdArCe4Ot98t1aR4eYiYTe%3DyavQygiQ%40mail.gmail.com https://www.postgresql.org/message-id/flat/CAEepm%3D0uEQCpfq... Proposal to add versions to libc collations in FreeBSD: https://reviews.freebsd.org/D17166 https://reviews.freebsd.org/D17166