FWIW, RubyMine does notice when a file has been modified on disk. If you have unsaved changes in RubyMine, it pops up an alert that lets you pick which to keep

FWIW, RubyMine does notice when a file has been modified on disk. If you have unsaved changes in RubyMine, it pops up an alert that lets you pick which to keep or to diff the two; if you don't have changes it just refreshes and shows the version on disk.