[Sugar-devel] On datastore object IDs

[Benjamin M. Schwartz]

Eben Eliason wrote:
> Anyway, the subtler point here, just for the sake of stating it
> outright, is that sending an object to someone and sharing that
> activity with them are (as they should be) quite different actions. In
> the former case, they just get the object, and can use it as the
> starting point for their own modifications, with their own history. In
> the latter case, they will wind up with an object with the same
> tree_id (and even version_id, for that matter) as the person who
> shared it.

If version_id is meant to be preserved across shared sessions, then:

1.  If I join someone else's shared session after it has been created,
then I might have version "1.1.1" but no previous version.  If I join
again later, I might also get "1.1.1.3.2", with a gap in my version history.

2. Even weirder, if two people produce new versions independently, they
will both get the same version_id, despite being entirely distinct objects.

I conclude that either (a) version_id`s cannot be preserved or (b)
version_id`s must be selected so as to be unique (e.g. based on large
random numbers).

>> Ok.  Maybe we need some new vocabulary like "read/write metadata" vs.
>> "read-only metadata".  Action<->Document references would have to live in
>> "read-only" metadata, managed by the Datastore.
> 
> That seems like a reasonable split, but I'm not sure it falls on the
> same line as versioned/un-versioned.

I agree; they are not the same.

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