Correct, user_runtime_directory wasn't configured, XDG_RUNTIME_DIR and RUNTIME_DIRECTORY not set, neither are TMPDIR or TMP. Apologies I forgot to mention I have a patch in 1.9.1 to use…
Looks like platformdirs uses ~/Library/Caches/TemporaryItems/$appname/$version for this purpose on MacOS. Not sure if that would work here or not?
btw I'm not the person who was having problems with TMPDIR (I'm running borgmatic on OpenBSD rather than MacOS). /tmp on other OS is not user specific (and often can't be, because it may be used…
Ah, I see borgmatic uses ~/.local/state/borgmatic for checks now, maybe that would be a better place for these files too..
A static (predictable) file or directory name in a world-writable TMPDIR or TEMP isn't safe, some other user on the system could create it and prevent borgmatic from working. (That's presumably…