schema updates and cn=config

["E.S. Rosenberg" <esr+openldap@g.jct.ac.il>]

Hi all,
I was wondering about the following thing (after just reading the long
cn=config thread), programs may distribute .schema files only, in
which case as already pointed out you should:
1. Request in a friendly manner that they provide an ldif if possible
2. convert it yourself using slaptest and add it using ldapadd/modiy etc.

The question I had is like this, a project may update/change it's
schema and if they ship only .schema files or .ldif that assume that
the schema is not loaded yet (ie. that do the initial add and not
modify operations, what you would also get from a .schema conversion)
then you are it would seem to me a bit stuck because you either:
- have to unload the old schemas (using ldapmodify) which leaves you
with invalid entries in your DIT while their schema is missing
or
- you have to manually figure out what the differences are between the
currently loaded schema and the new version of the schema (diff may be
helpful there) and the manually create an ldif that does all the
necessary modify operations.

So I was wondering if there is any way to generate a "diff-ldif" (for
lack of a better name) automatically to update the schema based either
on provided ldifs or provided .schema files (after conversion).

Obviously the other way is to ask the project in a friendly way that
they provide said "diff-ldifs" as well as regular ldifs.

Maybe I am completely wrong but so far this is what I understood from
all the manuals etc.

Thanks for all your great work,
Eli