When upgrading to 1.0-alpha the system attempts to convert old style tags into the new term_taxonomy structure.
This appears to fail due to a required "description" column, that is not set in the import process.
This appears to be an issue in both alpha and the current trunk.
Details: The function function bb_upgrade_1080() around line 881 of upgrade-functions.php has the following code...
$bbdb->insert( $bbdb->term_taxonomy, array(
'term_id' => $term_id,
'taxonomy' => 'bb_topic_tag'
) );
This insert will fail be cause bb_term_taxonomy is created with a description field that is NOT NULL. As indicated by the code around line 101 of upgrade-schema.php
// term_taxonomy
$bb_queries['term_taxonomy'] = "CREATE TABLE IF NOT EXISTS `$bbdb->term_taxonomy` (
`term_taxonomy_id` bigint(20) NOT NULL auto_increment,
`term_id` bigint(20) NOT NULL default 0,
`taxonomy` varchar(32) NOT NULL default '',
`description` longtext NOT NULL,
`parent` bigint(20) NOT NULL default 0,
`count` bigint(20) NOT NULL default 0,
PRIMARY KEY (`term_taxonomy_id`),
UNIQUE KEY `term_id_taxonomy` (`term_id`, `taxonomy`)
);";
