[development] Trouble with upgrade paths from different branches

[Fredrik Sandve Kilander]

Hello. I am having trouble with hook_update_N(). My module (yr_verdata) has two branches for D6, and I want to provide an upgrade path from both of these to D7. However, I can't seem to get the correct schema version when upgrading. In my install file i have the following:

function yr_verdata_update_7000(&$sandbox) {

  // Check to see what schema we are updating from.
  // If we are going from 6.x-2.x to 7.x-1.x, the schema is already ready for
  // 7.x-1.x so we just update the schema version number.
  $version = drupal_get_installed_schema_version('yr_verdata', TRUE);

  if ($version > 6199) { // Updating from 6.x-2.x, no problem.
    drupal_set_installed_schema_version('yr_verdata', 7000);
  }

  else { // Updating from 6.x-1.x, modify the database table.
    // Some update logic.
  }

  return t('Some friendly message');

}

The problem here is that drupal_get_installed_schema_version() simply returns 6999, no matter what. What am I doing wrong?

I could just remove the update logic that messes with the database table from the 7.x branch doing it all in 6.x-2.x, and require 6.x-1.x users to upgrade to 6.x-2.x before going to 7.x-1.x - but that sounds like a bad idea to me, and just extra work for people who want to upgrade to D7 with this module.

Any help is appreciated!