“call-with-file-lock” and “call-with-file-lock/no-wait” create a lock file but don’t remove the lock file when they exit.
(guix build syscalls) defines these procedures with “dynamic-wind” so that the lock is always lifted with “unlock-file”. While “unlock-file” uses the fcntl syscall to remove the lock on the file, the lock file itself is not deleted. I think it should be deleted. When the lock file sticks around we may run into problems due to lock file ownership. For example, imagine a cron job running as a different user that upgrades the contents of a user profile. That cron job would leave behind an unlocked lock file owned by that user, preventing the owner of the profile from operating on the profile even though the lock has already been lifted with “unlock-file”. I propose letting either unlock-file or with-profile-lock delete the lock file. -- Ricardo
