LocalDirAllocator.ifExists calls AllocatorPerContext.ifExists, which accesses the localDirsPath variable that is uninitialised. Hence, any code that uses this API is likely to fail with a NullPointerException.
However, this API is currently not used anywhere else in trunk. The earlier usage was in IsolationRunner, that has since been removed via
Hence, we could remove this API for trunk, and if required, fix it for the 1.x branch.