Merge branch 'wip_MDL-46126_m28_passnulls' of https://github.com/skodak/moodle

diff --combined lib/db/upgrade.php
index acb4ade,932567a..fc405f7
--- 1/lib/db/upgrade.php
--- 2/lib/db/upgrade.php
+++ b/lib/db/upgrade.php
@@@ -1583,6 -1583,8 +1583,8 @@@ function xmldb_main_upgrade($oldversion
      }
  
      if ($oldversion < 2013021100.01) {
+         // Make sure there are no bogus nulls in old MySQL tables.
+         $DB->set_field_select('user', 'password', '', "password IS NULL");
  
          // Changing precision of field password on table user to (255).
          $table = new xmldb_table('user');
@@@ -3676,36 -3678,5 +3678,36 @@@
          upgrade_main_savepoint(true, 2014061000.00);
      }
  
 +    if ($oldversion < 2014062600.01) {
 +        // We only want to delete DragMath if the directory no longer exists. If the directory
 +        // is present then it means it has been restored, so do not perform the uninstall.
 +        if (!check_dir_exists($CFG->libdir . '/editor/tinymce/plugins/dragmath', false)) {
 +            // Purge DragMath plugin which is incompatible with GNU GPL license.
 +            unset_all_config_for_plugin('tinymce_dragmath');
 +        }
 +
 +        // Main savepoint reached.
 +        upgrade_main_savepoint(true, 2014062600.01);
 +    }
 +
 +    // Switch the order of the fields in the files_reference index, to improve the performance of search_references.
 +    if ($oldversion < 2014070100.00) {
 +        $table = new xmldb_table('files_reference');
 +        $index = new xmldb_index('uq_external_file', XMLDB_INDEX_UNIQUE, array('repositoryid', 'referencehash'));
 +        if ($dbman->index_exists($table, $index)) {
 +            $dbman->drop_index($table, $index);
 +        }
 +        upgrade_main_savepoint(true, 2014070100.00);
 +    }
 +
 +    if ($oldversion < 2014070101.00) {
 +        $table = new xmldb_table('files_reference');
 +        $index = new xmldb_index('uq_external_file', XMLDB_INDEX_UNIQUE, array('referencehash', 'repositoryid'));
 +        if (!$dbman->index_exists($table, $index)) {
 +            $dbman->add_index($table, $index);
 +        }
 +        upgrade_main_savepoint(true, 2014070101.00);
 +    }
 +
      return true;
  }