[Chandler-dev] IMPORTANT: Upcoming Chandler update will break compatibility

[Philippe Bossut]

Hi,

If you are dogfooding Chandler 0.7alpha4 or even using the Chandler 
trunk, you need to read the following email: a planned Chandler change 
will break compatibility with old data and the migration path will be 
more difficult than usual. Read the following carefully.

Following up on Morgen's recent email on the Office calendar (see 
http://lists.osafoundation.org/pipermail/chandler-dev/2006-November/007232.html 
for details), we decided it was safer to start with a clean slate on 
osaf.us. What this means is that Morgen will be committing a change on 
both the trunk *and* the 0.7alpha4 branch that will break collection 
sharing backward and forward compatibility. This will ensure that we 
won't have old Chandler meddling with new data or new Chandler messing 
up old data... This is good but it comes with a price.

**What it means for Chandler users (including 0.7alpha4 dogfooders)*
*
You will need to start with a fresh Chandler repository **and** fresh 
shared data. Don't rely on the "Restore settings" or "Restore published 
shares" features: **this will not work!**

**What you need to do before getting the new checkpoint*
*
The only safe migration path will be through a local ics file. The 
problem is that ics files save only events, no tasks or notes or emails: 
you will lose data in the process. In order to loose as little as 
possible, follow the here under guidelines:

- Start your old Chandler
- For each collection you own (i.e. of which you are the author):
. Go to the Task view
. Stamp as an event every task you want to migrate
. Do the same for the Email view and All view (if you have Notes around)
. Go to "File / Import/Export / Export events as iCalendar" menu and 
save your collection to an ics file
- You don't have to do anything for the collections you subscribed to: 
you'll need to subscribe to a newly created collection anyway

Even though, task and emails won't be saved entirely. In the export 
process, you'll loose:
- stamping information
- triage status
- reminders
- email addresses

**What you need to do after getting the new checkpoint*
*
As stated above, don't use the "Restore settings" or "Restore published 
shares": the new Chandler won't be able to subscribe to old shares anyway.

You'll need to:
- Start your new Chandler
- Set up your Account information using the "File / Accounts..." menu
- Import each ics file you created previously using the "File / 
Import/Export / Import iCalendar data" menu item
- For each collection, go to the "All" view and publish the collection 
to your osaf.us account using "Collection / Share <xxx>" where <xxx> is 
your collection name
- You'll certainly want to unstamp the eventness of former task items 
and restamp them as tasks as well as recreating some of the lost data 
(triage status, reminders)
- For other collections, subscribe to them ("Collection / Subscribe..." 
menu) using the new URLs posted by their authors (ask the author if 
needs be). For your convenience, we already published the Office 
calendar using the new schema:
. Read-write: 
http://osaf.us/cosmo/home/morgen/Office_Calendar?ticket=0102ef0f-2e7c-401c-8521-d68a4804d568 

. Read-only: 
http://osaf.us/cosmo/home/morgen/Office_Calendar?ticket=4bd0f803-1104-4f34-bad5-a460743d337e 


We apologize for the inconvenience. Clearly, as if we needed to be 
reminded, this episode underlines the importance of the schema migration 
and EIM work we recently started.

Stay tuned for Bear's message on when the checkpoint will be available 
(this will happen later this afternoon).

Cheers,
- Philippe