The ReopenException is raised internally if File::Tail gets suspicious something unusual has happend to the tailed file, e. g., it was rotated away. The exception is caught and an attempt to reopen it is made.

Methods
N
Attributes
[R] mode
Class Public methods
new(mode = :bottom)

Creates an ReopenException object. The mode defaults to :bottom which indicates that the file should be tailed beginning from the end. :top indicates, that it should be tailed from the beginning from the start.

Source: show 

# File lib/file/tail.rb, line 40
      def initialize(mode = :bottom)
        super(self.class.name)
        @mode = mode
      end