Drupal tips and tricks

Overview

Drupal 6 has a long-standing bug in the block module (as of 5/10/2011). This bug affects block caching mechanisms. The bug manifests itself if you have block caching enabled.

Once a module's blocks have been registered with the system (in the {blocks} table), the block's caching mode settings are never updated in the {blocks} table, regardless of subsequent cache flushes or other system updates. This is only a problem for modules that change the 'cache' info returned from hook_block op='list' calls.

Uninstalling and re-installing the module won't fix the problem due to another Drupal 6 bug.

More info

• Issue 235673
• Issue 735900
• Issue 1155634

This problem impacts any module that changes the caching mode returned in hook_block('info') operation. In particular, the views module allows you to edit a block view's caching mode after creation, but, due to this bug, the changes will never take effect, leading to much head-scratching.

More info

• Issue 257267

The fix

There are a few core patches available (see Issue 235673, above), but they may not apply cleanly to your Drupal 6 installation; I don't patch core unless there's a critical need. In this case, the patches failed to apply on the sites that needed the fix. So I created a simple custom module that implements the guts of the most recent patch.

Note: You can download the module in the Attachments section, below. Leave a comment if you find this module useful, or, if you have questions about it.

How do I move Drupal taxonomy terms from one vocabulary to another?

While you can use the excellent Taxonomy Manager module to move taxonomy terms between vocabularies, it's not always worth the trouble to install yet another module. For example, if you are doing this as a one-time merge of several vocabularies into a new vocabulary.

Here's the recipe:

1. Identify the vocabulary ids (vid) for the source vocabularies. In our example, the source vocabulary ids are 6, 7, 8, and 9.

Here's a handy PHP snippet to purge user accounts for all users who haven't created any nodes on your site. It's useful when you have a lot of users who have signed but haven't created any nodes.

Drupal 5 and later versions provide an animation when you expand or collapse a collapsible form fieldset.

While this is a nifty effect, it can be annoying to some users, and it can slow you down when viewing a web page over a Remote Desktop session in Windows (I use Remote Desktop a lot at home, and the expand/collapse animation can take seconds to complete depending on network speed–it all adds up).

Our collection of Drupal-specific tips.