[imp] Problems migrating horde_prefs identities field from Horde 2.x to Horde 3.x

[Shaun Ferguson]

Hello,

We recently updated from Horde 2.x cvs to Horde 3.x cvs (around January 
21 this year), and all is mostly well with our migration except for the 
identities that our previous users had in their horde_prefs table. 

None of their previous identities will appear in the new Personal 
Information preference page, nor are they accessable from the Compose 
drop-down selector.  We have, with a test account, deleted the old 
version of the identities array for that account, and then added a new 
identity from the web interface to look at the changes to the field.  We 
have tried resolving the differences and reinserting the field values 
via mysql, but with mixed success.  So far, none of the old identity 
fields for other users have been successfully converted into something 
the new version of Horde/IMP will understand.

The following unserialize error messages in the logs appear to be 
related, which we have right now suppressed but need a real solution for: 

PHP Notice:  unserialize(): Error at offset 14 of 302 bytes in 
/usr/share/pear/Horde/Identity.php on line 75, referer: 
https://somewhere/horde/imp/mailbox.php?mailbox=INBOX
PHP Notice:  unserialize(): Error at offset 134 of 329 bytes in 
/usr/share/pear/Horde/Identity.php on line 75, referer: 
https://somewhere/horde/index.php?url=https%3A%2F%2Fsomewhere%2Fhorde%2F

We have searched the archive for possible answers, and the closest we 
have seen is that the users need to re-save their identities.  While 
this works for our test user, it is not a feasible solution to have the 
entirety of our user base (around 40,000 users) do this individually.  A 
scriptable conversion process is needed to migrate the old identity values.

A few version details:

Horde/IMP/Ingo/Turba/etc  is CVS from 01-21-2005
PHP version 4.3.4
PEAR is up-to-date as of 02-07-2005 (`pear upgrade-all`)
MySQL version 4.0.16

Any assistance that can be rendered is greatly appreciated.