Drupal Release: 6.15

TL;DR

Drupal 6.15 is primarily a maintenance release that focuses on documentation improvements, bug fixes, and performance enhancements. It addresses several issues including OpenID registration workflow, CSS aggregation problems, cache clearing performance, and various notices and warnings. This release is important for maintaining site stability and security, particularly for sites using OpenID authentication or with complex CSS structures.

Highlight of the Release

• Dramatically improved cache clearing performance using TRUNCATE
• Fixed OpenID registration workflow to handle errors better and allow users to prefill fields
• Preserved newlines in CSS aggregation to prevent breaking valid CSS structures
• Improved documentation for various API functions and hooks
• Fixed security update propagation from base themes to subthemes

Migration Guide

No specific migration steps are required for this maintenance release. Drupal 6.15 contains bug fixes and performance improvements that should not affect site functionality in a way that requires migration planning.

When upgrading from Drupal 6.14 to 6.15:

1. Back up your database and site files
2. Put your site into maintenance mode
3. Replace all core files and directories except for the sites directory
4. Run the update script by visiting update.php in your browser
5. Take your site out of maintenance mode

No database schema changes are included in this release, so the update process should be straightforward.

Upgrade Recommendations

This release is recommended for all Drupal 6 sites, especially those:

• Using OpenID for user authentication
• With complex CSS that might be affected by aggregation issues
• Running on PHP 5.3.x and using XML-RPC functionality
• Experiencing performance issues during cache clearing operations

The upgrade from Drupal 6.14 to 6.15 is a standard maintenance update with minimal risk. No database schema changes are included, making this a relatively safe upgrade that primarily addresses bugs and improves performance.

Sites should plan to upgrade during a regular maintenance window. The performance improvements, particularly for cache clearing operations, make this update worthwhile for most production sites.

Bug Fixes

• OpenID Registration Workflow: Fixed issues with the OpenID registration process when errors occur, allowing users to prefill fields when username or email address was not provided or invalid (#216101)
• CSS Aggregation: Fixed CSS aggregation to preserve newlines, preventing breakage of certain valid CSS structures (#472820)
• Module Update Status: Corrected an issue where modules could bubble up incorrectly in the update status listing if they had submodules earlier in alphabetical ordering (#319033)
• Release Date Tracking: Fixed wrong release dates being recorded on multi-module projects if deployed from CVS (#499828)
• XML-RPC Handling:
  • Fixed PHP 5.3.x failure when no parameters were provided to xmlrpc() by properly initializing the XML-RPC message params property (#647336)
  • Fixed notice in xmlrpcs.inc error handling (#208195)
• Anonymous User Contact Forms: Fixed issue where anonymous users should not have a contact form (#525504)
• Ping Module Performance: Fixed slow query in ping module and corrected its use of the database API (#336358)
• Search Form Validation: Fixed reference to non-existent search_box_form_validate() function in search form (#280319)
• Notice Prevention: Fixed notice when parsing an RSS feed with file attachments (#263517)
• Module List Clearing: Improved system.install to clear out module list and hook implementation statics before calling system_theme_data() (#375931)
• Menu Item Sorting: Fixed menu item sorting to be case insensitive, using lowercase titles for sorting (#528204)

New Features

No significant new features were introduced in this release. Drupal 6.15 is primarily a maintenance release focused on bug fixes, documentation improvements, and performance enhancements to existing functionality.

Security Updates

• PHP Script Caching: Enhanced security by preventing PHP scripts from being cached unless they explicitly send cache headers themselves (#550488). This helps prevent potential security issues related to inappropriate caching of dynamic PHP content.

• Theme Security Updates: Improved the propagation of security update information from base themes to subthemes (#456088), ensuring that security vulnerabilities in base themes are properly communicated to dependent subthemes.

Performance Improvements

• Cache Clearing: Dramatically improved performance when clearing caches by using TRUNCATE instead of DELETE queries (#644482). This change results in significant speed increases during cache clearing operations, which is particularly beneficial for larger sites.

• Ping Module Query: Fixed a slow query in the ping module by correcting its use of the database API (#336358), which improves performance when handling ping operations.

Impact Summary

Drupal 6.15 is a maintenance release that delivers important bug fixes and performance improvements without introducing breaking changes. The most significant impact comes from the dramatically improved cache clearing performance using TRUNCATE statements, which will benefit all sites, especially larger ones.

The fixes to OpenID registration workflow improve the user experience for sites using OpenID authentication, while the correction to CSS aggregation ensures that complex CSS structures remain intact during optimization. Developers will appreciate the extensive documentation improvements across various API functions and hooks.

Security is enhanced through better handling of PHP script caching and improved propagation of security update information to subthemes. The release also addresses several PHP notices and warnings, contributing to cleaner error logs and more stable operation.

Overall, this release represents an important maintenance update that improves stability, performance, and security without requiring significant adaptation from site owners or developers.