Can't override theme_date_display_combination($element), even after clearing the cache

I thought I was going to have a smart answer to this, but even after reading #592796: Date Filters not working in Views when multiple date fields are used I still see stuck on this. My version of theme_date_display_combination just won't get recognized. I guess I have to implement hook_theme_registry_alter in a module, but I'm trying to do that as a last resort...

Did you ever figure this out?

OK, now I do have something smart to say. You have to override date_formatter_short like so:

function themename_date_formatter_short($element) {
return themename_date_display_combination($element);
}

obviously defining themename_date_display_combination.

It's confusing because several date formatters use theme_date_display_combination. That's what got me. I overrode default and short, but not long, until not long (ha, ha) after I contacted the OP of the other issue.

Well, if anyone stumbles upon this, hopefully it'll help.

I guess I'll mark it as by design too since no module changes are needed?

Kevin

So, like gwtt said, the problem is that theme_date_display_combination() isn't really a theme function. Sure, it starts with 'theme_', but it's not linked in with date_theme anywhere. Instead, date_theme points various theme functions to theme_date_display_combination. So the best thing to do is something like this:

1) In your theme, which I will call 'foobar' for clarity, implement foobar_date_display_combination and make your changes inside of it.

2) Add this to your theme:

function foobar_theme() {
  $themes = array(
    'date_formatter_default' => array(
      'arguments' => array('element' => NULL), 
      'function' => 'foobar_date_display_combination'),  
  );
  // Table isn't available first time date_theme() is called in update.php.
  if (db_table_exists('date_format_types')) {
    $format_types = date_get_format_types('', TRUE);
    if (!empty($format_types)) {
      foreach ($format_types as $type => $type_info) {
        $themes['date_formatter_' . $type] = array(
          'arguments' => array('element' => NULL), 
          'function' => 'foobar_date_display_combination',
        );
      }
    }
  }
  return $themes;
}

Usually you don't need a hook_theme in a theme, but this time you do, because we're adding something more complicated to the theme than a usual replacement.

In D7 you can directly create a function yourthem_date_display_combination($vars) in your template.php without the need of hook_theme.