r21577 - gnucash/trunk/src/backend/xml - Fix xml backend to load and save invoice kvp values.

[John Ralls]

On Dec 7, 2011, at 6:43 AM, Derek Atkins wrote:

> Mike Alexander <mta at umich.edu> writes:
> 
>> --On December 6, 2011 3:01:54 PM -0800 John Ralls <jralls at ceridwen.us>
>> wrote:
>> 
>>>> This is not the optimal solution, but the best I can come up with in
>>>> my  available time and with the state of the backends as they are
>>>> now.
>>> 
>>> No, I think that's got it.
>>> 
>>> If you can't handle credit notes in 2.4 without too much of a change,
>>> you could detect them at load and raise ERR_BACKEND_TOO_NEW, though I
>>> admit that's not much of an improvement over failing to load because
>>> of an unrecognized element.
>> 
>> Could you bump the file version number only if credit notes exist in
>> the file?  Or bump it the first time a credit note is used (leaving it
>> bumped if all of them later get deleted)?  That might give you the
>> best of both worlds: strict versioning, but old versions of Gnucash
>> could open data files that don't use credit notes.
>> 
>> Actually you wouldn't literally bump it, but rather set it to n if it
>> is less than n (where n is the first version that supports credit
>> notes).  Would this work?
> 
> This is effectively my "feature" flags suggestion from before.  You flag
> (new) features as they are used, and refuse to load the database if
> there are used features that you don't understand.

Something to look at adding for 2.6 to get ready for the database overhaul in 2.8/3.0. It's not in 2.4, and it would need a new "feature" table to hold the features so it probably shouldn't go in.

Regards,
John Ralls