Issue #1425868 - Duplicate entry in the system table after upgrade fr…

…om Drupal 6.22 to 6.24.

modules/system/system.module

@@ -826,25 +826,21 @@ function system_theme_data() {
 
   // If lock not acquired, return $themes data without writing to database.
   if ($write_database) {
-    $names = array();
+
+    // Database is locked so no one else can change these settings, we are safe
+    // to delete everything and write out each of the records.
+    db_query("DELETE FROM {system} WHERE type = 'theme'");
 
     foreach ($themes as $theme) {
-      // Record the name of each theme found in the file system.
-      $names[] = $theme->name;
-      // Update the contents of the system table.
-      if (isset($theme->status) && !(defined('MAINTENANCE_MODE') && MAINTENANCE_MODE != 'install')) {
-        db_query("UPDATE {system} SET owner = '%s', info = '%s', filename = '%s' WHERE name = '%s' AND type = '%s'", $theme->owner, serialize($theme->info), $theme->filename, $theme->name, 'theme');
-      }
-      else {
+      // If status is missing, set it based on this theme name matching the
+      // configured default theme.
+      if (!isset($theme->status)) {
         $theme->status = ($theme->name == variable_get('theme_default', 'garland'));
-        // This is a new theme.
-        db_query("INSERT INTO {system} (name, owner, info, type, filename, status, throttle, bootstrap) VALUES ('%s', '%s', '%s', '%s', '%s', %d, %d, %d)", $theme->name, $theme->owner, serialize($theme->info), 'theme', $theme->filename, $theme->status, 0, 0);
       }
+      // Insert records back into the system table
+      db_query("INSERT INTO {system} (name, owner, info, type, filename, status, throttle, bootstrap) VALUES ('%s', '%s', '%s', '%s', '%s', %d, %d, %d)", $theme->name, $theme->owner, serialize($theme->info), 'theme', $theme->filename, $theme->status, 0, 0);
     }
-    // Delete from the system table any themes missing from the file system.
-    if ($names) {
-      db_query("DELETE FROM {system} WHERE type = 'theme' AND name NOT IN (". db_placeholders($names, 'varchar') .")", $names);
-    }
+
     lock_release('system_theme_data');
   }
   return $themes;