Availability Calendar breaks Page Theme module

On porting the code to D7, I found that the hook_init() did contain some code that the original developer himself had doubts about (comment: can't find a better way to do this). So I looked for a better way of adding the css and came up with the following code for D7:

old: see #2

new

function availability_calendars_init() {
  // css is added to all pages, since blocks will need to make use of it
  drupal_add_css(drupal_get_path('module', 'availability_calendars') .'/availability_calendars.css');

  $current_theme = variable_get('theme_default', 'none');

  // themes we will perform specific theming on
  $core_themes = array('garland', 'bluemarine', 'chameleon', 'marvin', 'pushbutton');
  $base_themes = array('fusion_core', 'tao', 'zen', 'ninesixty');

  $add_css = FALSE;
  // check to see if we are using a core theme
  if (in_array($current_theme, array_merge($core_themes, $base_themes))) {
    $add_css = TRUE;
  }
  else {
    // check whether the theme being used is a subtheme of one of our themed base themes
    $themes = list_themes();
    $theme = $themes[$current_theme];
    while (!empty($theme->base_theme)) {
      $theme = $themes[$theme->base_theme];
      if (in_array($theme->name, $base_themes)) {
        $add_css = TRUE;
        break;
      }
    }
  }
  if ($add_css) {
    drupal_add_css(drupal_get_path('module', 'availability_calendars') . '/css/' . $theme_key . '.css');
  }

Can you test and review this patch?

fietserwin, the developer here. I have an issue with what you are doing via variable_get(). This does not account for when users are allowed to select their own theme for the site. Any ideas about that? We need to determine which theme is actually in use.

You're right, but then I guess this can't be known in the init hook. The theme has not yet been initialized (when I was debugging through that piece of code I saw that our call to list_themes() was the first (the static inside had not yet been initialized). Moreover other modules exist that can change the theme in use on a per page/user or whatever basis.

So I think if you really want to solve this, you have to do it in a hook that's later in the process (or assure you're the last to init, as I guess that the choice of theme will be made in the init phase).

Some links:
- http://drupal.org/node/224333#custom_theme
- http://api.drupal.org/api/drupal/developer--globals.php/global/custom_th...

For D7 it turns out that theme initializing is done before hook_init (guess why). So, we may assume that in hook_init we have available the globals $theme_info and $base_theme_info. So for D7 I was able to rewrite this part cleanly:

  // Theme specific css
  $add_theme_specific_css = FALSE;

  // Themes we will perform specific theming on
  $core_themes = array('garland', 'bluemarine', 'chameleon', 'marvin', 'pushbutton');
  $base_themes = array('fusion_core', 'tao', 'zen', 'ninesixty');

  // Check to see if we are using a core theme
  global $theme_info, $base_theme_info;
  $theme = $theme_info;
  if (in_array($theme->name, array_merge($core_themes, $base_themes))) {
    $add_theme_specific_css = TRUE;
  }
  else {
    // Check whether the theme being used is a subtheme of one of our themed base themes
    while (!empty($theme->base_theme)) {
      $theme = $base_theme_info[$theme->base_theme];
      if (in_array($theme->name, $base_themes)) {
        $add_theme_specific_css = TRUE;
        break;
      }
    }
  }
  if ($add_theme_specific_css) {
    drupal_add_css(drupal_get_path('module', 'availability_calendars') . '/css/' . $theme->name . '.css', array('every_page' => TRUE));
  }

D6 has the same globals, but we can not assume that they have been set in hook_init, However in a theme function they will be set. So,in D6, we could move this code to the theme_availability_calendars_node() function. In that case, it will not be rendered as often, only when necessary, so it may lead to another aggregation. How bad is that?

Considering:
- the difficulties we have in determining the actual theme that will be used on a given page (see comments #3, #4, #6, and #7)
- the fact that in the 6.x-2.x branch this problem has been removed by rewriting the styling stuff, so we don't do any theme specific includes anymore
- the fact that this errors only surfaces in some configurations (no single theme in use; modules changing theme in the init phase, ...???)

I am going to close this call as a won't fix.

Note that the 6.x-2.x branch will *not* suffer from this error. Thus if you are experiencing this issue, please upgrade to the 6.x-2.x branch (and don't forget to run update.php).