Python 3.12.10 | Windows-11-10.0.26200-SP0 | cpus 24 procs=5 files=60 rounds-per-cell=10 demo (Windows only): 1. rename while another handle holds an ordinary open(): PermissionError, WinError 32 2. a handle opened before the rename with delete sharing: rename succeeded, and the handle now reports the new name: e.txt timing rule rounds | once twice nobody | failed verify-opens: not-found denied other | rounds with a double claim barrier plain 10 | 1 599 0 | 0 0 0 | 10 barrier verify 10 | 596 0 4 | 2294 66 0 | 0 barrier retry 10 | 600 0 0 | 2341 0 0 | 0 free plain 10 | 180 420 0 | 0 0 0 | 10 free verify 10 | 598 0 2 | 800 93 0 | 0 free retry 10 | 600 0 0 | 834 0 0 | 0 rounds that did not end cleanly: 0