SONAME migration: should the symbols file be continued?

[Osamu Aoki <osamu@debian.org>]

Hi,

As I understand, when a library generated from a foo source packge moves
to a new SONAME, we change its library package name:
  library file:    libfoo.so.1 -> libfoo.so.2
  library package: libfoo1     -> libfoo2

But what should we do with the symbols file as the BEST PRACTICE?

Should we start with:
 $ mv debian/libfoo1.symbols debian/libfoo2.symbols  --- case #1

or, should we start fresh with:
 $ : >debian/libfoo2.symbols                         --- case #2

After doing the basics (like removing Debian revision -1), we may end up
like:

For case #1:
libfoo.so.2 libfoo2 #MINVER#
  foo_get_name@Base 1.1
  foo_get_longname@Base 1.2
  foo_get_type@Base 1.1
  foo_get_longtype@Base 2.1
  foo_get_symbol@Base 1.1
  foo_get_rank@Base 1.1
  foo_new@Base 1.1
  ...

For case #2:
libfoo.so.2 libfoo2 #MINVER#
  foo_get_name@Base 2.1
  foo_get_longname@Base 2.1
  foo_get_type@Base 2.1
  foo_get_longtype@Base 2.1
  foo_get_symbol@Base 2.1
  foo_get_rank@Base 2.1
  foo_new@Base 2.1
  ...

I understand that either case should work fine for the next upstream
release 2.2.  But which is better and why is it?

Case #1 keeps the history (but that part of history is not really used).

Case #2 is cleaner.  But missing data.

I am doing case #1 now but wondering why by myself...

Osamu