I haven't seen this mentioned yet which makes me wonder if I've misunderstood, but isn't it already the case that bash runs in a posix-compatible mode if executed as /bin/sh? I remember a bug a while back [1] that broke graphical login because flatpak used a bashism in an X startup script. Does this not imply that any bashisms executed with /bin/sh would already be causing breakage today on Arch Linux? [1] https://bugs.archlinux.org/task/61420#comment176360
