- _newest_step steps the cached newest order only when the per-file cache
still holds exactly the values this call built. A stale page read racing
a newer warm build (both run in executor threads) stored an order
labelled with older values than it held, and the next read inserted the
new file a second time. It also sorts in full when a roots reset dropped
the per-file values meanwhile.
- The stored spelling is checked on Windows too (nt._getfinalpathname:
realpath keeps the given case when it cannot open the file), and before
the name filters, which compare the walk's stored spelling. macOS opens
non-blocking, so a FIFO named like an image never holds the executor.
- An output in a folder the walk cannot list (no read permission) is not
added, as the walk skips it.
- Windows-portable unit tests: POSIX paths in the insert tests, and a
str.lower fold for the length guard (Windows' normcase keeps lengths).
Vito Sansevero
aeffe87dc1