Re: Adding missing copyright years

[Glenn Morris <gmorris+emacs@ast.cam.ac.uk>]

I'm trying to update the copyright in lisp/calendar, and am finding it
really tough to do a good job. FWIW, my algorithm is something like
this:

1. Make a CVS diff between 00:00 on January first of two consecutive
   years.

2. Work out the "number of lines" changed, bearing in mind that
   renaming "foo" to "bar" in lots of places counts for only one line,
   etc, etc.

3. If the number of lines changed is less than 10-15, carry the number
   forward to the next year, and add it to any changes made that year.
   If the running total becomes greater than 10-15 in any year, add a
   copyright for that year, and reset the running total to zero.

4. Modulate the above with the fact that when Emacs was not available
   via CVS, only years in which releases were made are eligible to be
   in copyright headers. So counts of changed lines should be
   accumulated until release years.

5. Keep track of code deletions. If, at any point, enough code is
   deleted so that the only remaining changes from some past year are
   no longer significant, then that year should not appear in
   copyright headers from that point onwards. This is a real PITA.


Bloomin' lawyers. Grrr...