Index: modules/block/block.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/block/block.module,v
retrieving revision 1.307
diff -u -r1.307 block.module
--- modules/block/block.module	26 May 2008 17:12:54 -0000	1.307
+++ modules/block/block.module	28 Jun 2008 17:00:23 -0000
@@ -256,11 +256,16 @@
           $blocks[] = $block;
         }
         else {
-          // If it's an existing block, database settings should overwrite
-          // the code. But aside from 'info' everything that's definable in
-          // code is stored in the database and we do not store 'info', so we
-          // do not need to update the database here.
-          // Add 'info' to this block.
+          // For existing block, database settings should overwrite the code,
+          // except for possible changes in the cache mode.
+          if ((!isset($block['cache']) && $old_blocks[$module][$delta]['cache'] != BLOCK_CACHE_PER_ROLE) || (isset($block['cache']) && $old_blocks[$module][$delta]['cache'] != $block['cache'])) {
+            $updated_block = array('cache' => isset($block['cache']) ? $block['cache'] : BLOCK_CACHE_PER_ROLE, 'module' => $module, 'delta' => $delta);
+            drupal_write_record('blocks', $updated_block, array('module', 'delta'));
+            cache_clear_all("$module:$delta:", 'cache_block', TRUE);
+            $old_blocks[$module][$delta]['cache'] = $updated_block['cache'];
+          }
+          // 'info' is the only thing that's definable in code but not stored
+          // in the database.
           $old_blocks[$module][$delta]['info'] = $block['info'];
           // If the region name does not exist, disable the block and assign it to none.
           if (!empty($old_blocks[$module][$delta]['region']) && !isset($regions[$old_blocks[$module][$delta]['region']])) {