Status:
There's code for safe compaction on MS Windows now.
https://github.com/apache/jena/pull/2321
There are non-deterministic test failures build on MS Windows only, and
more likely when the build server is busy.
A few more details on
https://github.com/apache/jena/issues/2328
https://github.com/apache/jena/pull/2329
I'd like to proceed with Jena 5.0.0 with the partial improvement applied
and then clean the rest of the cases, allowing for any proper rewrites
to improve an area of code, rather than only fixing the presenting problem.
Andy