What I do when I run into these problems is to publish checkpointed sets 
of changes as different versions.  The loading instructions specify that 
in order to migrate, say, package X version 3.0 (without changes) to 3.1 
(with changes), one has to load 3.0.1, 3.0.2, ..., 3.0.k in sequence, 
after which 3.1 is loaded.  So, in your case, k would be about 20.  This 
has the nice side effect of clearly documenting each stage of the changes.

Luciano and myself did something similar for the hash changes back in 
2000.  At that time, 7 checkpointed changesets in the update stream 
changed the symbol table (and things like Symbol>>hash) under the 
running system.  I never heard of any issues with that... hopefully 
there were actually none.

My 2 cents,
Andres.


Eliot Miranda wrote:
> Hi All,
>
>     I'm embarrased to say that part of my ork environment revolves 
> around ChangeSets.  While I very happily use Monticello I also have 
> the Closure bootstrap strewn across a number of change sets, about 20 
> in all.  Because the Closure bootstrap is complicated, with different 
> variations for Squeak 3.9, Croquet etc, with different stages in 
> self-modification of the compiler, etc, it can't be written as a set 
> of Monticello packages.
>
> But for the second time I am about to hit my changes file limit and, 
> because of Monticello overrides and my own method history, I do not 
> want merely to condense changes and continue.  Instead what I want to 
> do is move my change sets to a more up-to-date image.  At Qwaq Andreas 
> builds weekly images whose end result includes the result of the 
> Closure bootstrap.
>
> What I would like to do is serialize all my change sets, file-out all 
> my changes (idelaly including history) and then in an up-to-date 
> deserialise the change sets to preserve the structure, and selectively 
> file-in those changes that are different to the up-o-date image (I 
> haven't thought this last point through too carefully; presumably all 
> the changes are in the up-to-date image, so what I really want to 
> bring in somehow is the history).
>
> What I wondered was has anyone else gone throguh something similar and 
> if so do they have any code that would help me, war stories that would 
> change my mind, or alternatives (e.g. how to preserve Monticello 
> overrides through a condense changes).
>
> AdvThanksance
>
> Eliot
>