The RFC section on filesystems that reject the atomic no-replace rename
still described the retired existence-check-plus-plain-rename fallback
and its accepted race window. The implementation (and the npm and shell
surfaces) claim the destination with mkdir or a hard link — or create
the link directly at the destination — and never release the claim mid
transaction, so a concurrently created object is refused rather than
overwritten. Record that contract and its only relaxed property (child
moves are not all-or-nothing visible) so future maintainers do not
port the racy description back into code.
玉澜
7fa4ee7bac