Steps to reproduce the issue

Upgrade from 2.5.28 (clean install with sample data) to 3.5.0 beta 5 using custom URL: https://downloads.joomla.org/updates/cms/test/list_test_25to3x.xml.

Expected result

Joomla upgraded without issues.

Actual result

You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '--ALTER TABLE #__redirect_links MODIFY new_url varchar(255)' at line 5 SQL=-- -- The following statement has to be disabled because it conflicts with -- a later change added with Joomla! 3.5.0 for long URLs in this table -- --ALTER TABLE #__redirect_links MODIFY new_url varchar(255);

And joomla backend gets broken. 500 error on several backend pages after update.

System information (as much as possible)

Database Version: 5.5.5-10.0.24-MariaDB
PHP Version: 5.6.18

Additional comments

I think this only happens when upgrading from 3.3.6 or lower versions to 3.5.0 beta 4/5.

Maybe problem with sql comment (missing space after --)?

• https://github.com/joomla/joomla-cms/blob/staging/administrator/components/com_admin/sql/updates/mysql/3.4.0-2014-09-16.sql#L6

• https://github.com/joomla/joomla-cms/blob/staging/administrator/components/com_admin/sql/updates/postgresql/3.4.0-2014-09-16.sql#L6

• https://github.com/joomla/joomla-cms/blob/staging/administrator/components/com_admin/sql/updates/sqlazure/3.4.0-2014-09-16.sql#L6

Can this also be the cause of the 500 error observed before on upgrade from lower versions?

@richard67 can you check this one?