Upgrade fails from version 1.9 - 2.0

I just had a look into this.

I think the problem could be that you must install ctools before you upgrade Ultimate Cron to 7.x-2.x.

Could you verify my assumption? If so I'll add it to the upgrade section on the module page and to hook_requirements().

A change could look something like this:

diff --git a/ultimate_cron.install b/ultimate_cron.install
index 747fdc8..f386842 100755
--- a/ultimate_cron.install
+++ b/ultimate_cron.install
@@ -271,6 +271,18 @@ function ultimate_cron_requirements($phase) {
     case 'install':
       return $response;

+    case 'update':
+      if (!module_exists('ctools')) {
+        $t = get_t();
+        $ctools['title'] = 'Ultimate Cron';
+        $ctools['value'] = $t('Error');
+        $ctools['severity'] = REQUIREMENT_ERROR;
+        $ctools['value'] = $t('Chaos tool suite (ctools) is not enabled!');
+        $ctools['description'] = $t('You must install and enable Chaos tool suite (ctools) before upgrading Ultimate Cron.');
+        $response['ultimate_cron'] = $ctools;
+      }
+      return $response;
+
     case 'runtime':
       $t = get_t();
       $response['title'] = 'Ultimate Cron';
diff --git a/ultimate_cron.module b/ultimate_cron.module
index 6db5d04..ea0e295 100755
--- a/ultimate_cron.module
+++ b/ultimate_cron.module
@@ -724,7 +724,12 @@ function ultimate_cron_ultimate_cron_job_list() {
  * Implements hook_flush_caches().
  */
 function ultimate_cron_flush_caches() {
-  return array('cache_ultimate_cron');
+  $bin = 'cache_ultimate_cron';
+  $cache = _cache_get_object($bin);
+  if (($cache instanceof DrupalDatabaseCache) && !db_table_exists($bin)) {
+    return array();
+  }
+  return array($bin);
 }

 /**

The change to ultimate_cron_flush_caches() to catch for the situation where some cache clear runs before the cache table has been created.

That would at least catch the situation where someone tries to enable ctools but has already upgrade the ultimate_cron code to 7.x-2.x (and you're using database cache).

I'm not sure adding that overhead to each cache clear is worth it, though.

Ok, good to know.

The only way I was able to trigger this so far was when missing ctools.

So the problem appears to be something triggering a cache clear before running all the update hooks of Ultimate Cron 2.x.

A couple of questions just to try to narrow it down:

1. Do you do update any thing else together with Ultimate Cron? If yes, try to update only Ultimate Cron.
2. Could you look in the database for the current registered schema_version of Ultimate Cron before the update? (SELECT schema_version FROM system WHERE name = "ultimate_cron";)

Thank you, @rviner.

Weird. Nothing wrong with schema_version or anything else apparently. Except not working :-)

Ultimate Cron 7.x-2.x creates a new cache table in update hook ultimate_cron_update_7202(). The cache table is then added hook_flush_caches()/ultimate_cron_flush_caches() (as should be).

The problem must be that something on this one particular site triggers a clear cache before ultimate_cron_update_7202() get a chance to run.

Any chance you'll be able to debug into when/where that happens?

Glad you found your way around this!

I add a update requirements check on the existence of ctools. Although this was not your root cause it was at least a potential error for some users.

I'll close this and create a 7.x-2.2 release.