Re: Changing enum labels considered harmful

["C. M. Heard" <heard@pobox.com>]

On Fri, 17 Jan 2003, Juergen Schoenwaelder wrote:
> 
> Mike> I think it was a mistake for the SMI to allow labels associated
> Mike> with existing enumerations and bit positions to be changed when
> Mike> a module is revised, and I believe that the practice should be
> Mike> forbidden in revisions of IETF MIB [modules].  If others on the
> Mike> mreview list agree with this, I'll put some words to that effect
> Mike> in the MIB author's and reviewer's guide, and Juergen or Frank
> Mike> might want to consider adding an equivalent item to the on-line
> Mike> SMI errata list.
> 
> I think it is fine to explain the problem in the guide and to
> recommend to not change labels. Whether this is indeed considered to
> be a bug in the SMIv2 specification probably requires more concensus
> and we will get back to the question how much a language should
> allow/disallow and how much concrete usage guidelines should
> allow/disallow.

Understood.  The reason why I hold to the position that it is a bug
is that (a) it breaks backward compatibility and (b) similar practices
that break backward compatibility (in particular, changing the
descriptor of an existing object) are explicitly banned).  I'll
move the discussion of that part of the issue over to the
mibs@ops.ietf.org list.

//cmh