empty sidebars in all themes
I became admin of a drupal site which and as been dormant for a while, its 4.7, so before doing anything, i decided to upgrade it to 5.9.
i copied the whole site to a test server, including the db, and committed the procedure to upgrade. The site uses the Fern theme, which only is supposed to work in 4.7.
I ignored this and went ahead with upgrading anyhow.
Now Im in 5.9, and everything looks decent, only the sidebars remain empty! I looked for ten times in the template files, and i tried all other templates there are, but whatever i do, i never get any of the sidebars to have any content, display a block, etc.
What could this be? The variables $sidebar_left and $sidebar_right seem to remain empty. This doesnt have anything to do with the theme right? Is it something with the upgrade which might have gone wrong?
Im basically a n00b at drupal, but i do know my way around in php.

It probably is a theme (configuration) issue
Sidebars are regions defined in the theme. Generally, you need to publish blocks (or menus, etc) in specific regions for each theme. Take a look at /admin/build/block and you'll find options for each of your enabled themes.
Mel
no it isnt :(
hi Mel,
thanks, and i've been looking there, and applying many different themes.
If I instruct to just print the contents of $sidebar_left it remains empty, no matter what the theme, or how many blocks i place with undue weight on it in the admin....
its a database issue...
ive installed a fresh version of DP 5.9, with the fern theme, and the sidebar was there.
Then I put the db of my old db, and the sidebar was gone.
So good news and bad news - its not the theme, but what on earth goes wrong in the DB?
blocks table is wrong
so i narrowed it down to the blocks table - after trying the variables and block-roles-tables.
to fix the hiddeness of the blocks, i dropped the block table from my original drupal installation, and executed the mysql query from the fresh installed version. then i copied the settings from the original site for the blocks, and all is like i want it.
so this is some kind of an issue with the migration script. quite annoying.
This is a real issue
This is a real issue. I'm using latest 5.x (5.10 as of 2008-09-13) and suddenly $left_sidebar and $right_sidebar started to show up empty on page.tpl.php. I was just tweaking a block in a custom module when the bug was triggered.
This problem is very annoying because Drupal provides no clue of what is wrong. There's no log entries. A look on the database is also of not of much help (at least for the average Drupal developer like me). The sidebars simply don't show up anymore.
Switch to another theme and $sidebar_* are populated again. Switch back to your original theme and the sidebars are gone.
The fix was to drop the blocks table and recreate (see http://drupal.org/node/135175#comment-956180). Notice that this is not a trivial task -- one must backup de database and some data is lost in the process (you must reenter some block settings on the UI after doing this).
Unfortunately I didn't keep track of what I did to trigger the bug, and I coudn't reproduce it after fixing it.
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