admin/build/block should show in admin theme

The Blocks page uses the front end theme because it's previewing the block positions while you setup your blocks (which is usually more important for the front end theme than the admin theme). I'm not sure if/how this can be overridden, but it's not a bug.

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"Give a man a fish and you feed him for a day.
Teach a man to fish and you feed him for a lifetime." -- Lao Tzu
"God helps those who help themselves." -- Benjamin Franklin
"Search is your best friend." -- Worldfallz

Just an fyi-- this has been fixed in d7!

I have managed to successfully force the blocks module to use the admin theme without side-effects. Yes, core needs to be hacked to do this, there does not seem to be a way around that in Drupal 6. I am using Drupal 6.16.

The changes needed are below. I made about a dozen changes in 2 files and 4 functions. Every time I changed something, I added a comment "// core hacked" to the end of the line. I also kept a commented-out copy of the each line I changed right before the change.

If you want to use these changes, I suggest copying them as whole functions and paste them over existing functions.

block.module: 1 function changed

function _block_rehash($theme = NULL) { // core hacked: added
//function _block_rehash() { // core hacked: removed
  global $theme_key;

  init_theme();
  $theme = isset($theme) ? $theme : $theme_key; // core hacked: added

  //$result = db_query("SELECT * FROM {blocks} WHERE theme = '%s'", $theme_key); // core hacked: removed
  $result = db_query("SELECT * FROM {blocks} WHERE theme = '%s'", $theme); // core hacked: added
  $old_blocks = array();
  while ($old_block = db_fetch_array($result)) {
    $old_blocks[$old_block['module']][$old_block['delta']] = $old_block;
  }

  $blocks = array();
  // Valid region names for the theme.
  //$regions = system_region_list($theme_key); // core hacked: removed
  $regions = system_region_list($theme); // core hacked: added

  foreach (module_list() as $module) {
    $module_blocks = module_invoke($module, 'block', 'list');
    if ($module_blocks) {
      foreach ($module_blocks as $delta => $block) {
        if (empty($old_blocks[$module][$delta])) {
          // If it's a new block, add identifiers.
          $block['module'] = $module;
          $block['delta']  = $delta;
          //$block['theme']  = $theme_key; // core hacked: removed
          $block['theme']  = $theme; // core hacked: added
          if (!isset($block['pages'])) {
            // {block}.pages is type 'text', so it cannot have a
            // default value, and not null, so we need to provide
            // value if the module did not.
            $block['pages']  = '';
          }
          // Add defaults and save it into the database.
          drupal_write_record('blocks', $block);
          // Set region to none if not enabled.
          $block['region'] = $block['status'] ? $block['region'] : BLOCK_REGION_NONE;
          // Add to the list of blocks we return.
          $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.
          $old_blocks[$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']])) {
            drupal_set_message(t('The block %info was assigned to the invalid region %region and has been disabled.', array('%info' => $old_blocks[$module][$delta]['info'], '%region' => $old_blocks[$module][$delta]['region'])), 'warning');
            $old_blocks[$module][$delta]['status'] = 0;
            $old_blocks[$module][$delta]['region'] = BLOCK_REGION_NONE;
          }
          else {
            $old_blocks[$module][$delta]['region'] = $old_blocks[$module][$delta]['status'] ? $old_blocks[$module][$delta]['region'] : BLOCK_REGION_NONE;
          }
          // Add this block to the list of blocks we return.
          $blocks[] = $old_blocks[$module][$delta];
          // Remove this block from the list of blocks to be deleted.
          unset($old_blocks[$module][$delta]);
        }
      }
    }
  }

  // Remove blocks that are no longer defined by the code from the database.
  foreach ($old_blocks as $module => $old_module_blocks) {
    foreach ($old_module_blocks as $delta => $block) {
      //db_query("DELETE FROM {blocks} WHERE module = '%s' AND delta = '%s' AND theme = '%s'", $module, $delta, $theme_key); // core hacked: removed
      db_query("DELETE FROM {blocks} WHERE module = '%s' AND delta = '%s' AND theme = '%s'", $module, $delta, $theme); // core hacked: added
    }
  }
  return $blocks;
}

block.admin.inc: 3 functions changed

function block_admin_display($theme = NULL) {
  global $custom_theme;

  // If non-default theme configuration has been selected, set the custom theme.
  //$custom_theme = isset($theme) ? $theme : variable_get('theme_default', 'garland'); // core hacked: removed
  $theme = isset($theme) ? $theme : variable_get('theme_default', 'garland'); // core hacked: added

  // Fetch and sort blocks
  //$blocks = _block_rehash(); // core hacked: removed
  $blocks = _block_rehash($theme); // core hacked: added
  usort($blocks, '_block_compare');

  return drupal_get_form('block_admin_display_form', $blocks, $theme);
}

function block_admin_display_form(&$form_state, $blocks, $theme = NULL) {
  global $theme_key, $custom_theme;

  // Add CSS
  drupal_add_css(drupal_get_path('module', 'block') .'/block.css', 'module', 'all', FALSE);

  // If non-default theme configuration has been selected, set the custom theme.
  //$custom_theme = isset($theme) ? $theme : variable_get('theme_default', 'garland'); // core hacked: removed
  $theme = isset($theme) ? $theme : variable_get('theme_default', 'garland'); // core hacked: added
  init_theme();

  $throttle = module_exists('throttle');
  //$block_regions = system_region_list($theme_key) + array(BLOCK_REGION_NONE => '<'. t('none') .'>'); // core hacked: removed
  $block_regions = system_region_list($theme) + array(BLOCK_REGION_NONE => '<'. t('none') .'>'); // core hacked: added

  // Weights range from -delta to +delta, so delta should be at least half
  // of the amount of blocks present. This makes sure all blocks in the same
  // region get an unique weight.
  $weight_delta = round(count($blocks) / 2);

  // Build form tree
  $form = array(
    '#action' => arg(4) ? url('admin/build/block/list/'. $theme_key) : url('admin/build/block'),
    '#tree' => TRUE,
  );
  $form['_theme'] = array( // core hacked: added
      '#type' => 'hidden', // core hacked: added
      '#value' => $theme, // core hacked: added
  ); // core hacked: added

  foreach ($blocks as $i => $block) {
    $key = $block['module'] .'_'. $block['delta'];
    $form[$key]['module'] = array(
      '#type' => 'value',
      '#value' => $block['module'],
    );
    $form[$key]['delta'] = array(
      '#type' => 'value',
      '#value' => $block['delta'],
    );
    $form[$key]['info'] = array(
      '#value' => check_plain($block['info'])
    );
    $form[$key]['theme'] = array(
      '#type' => 'hidden',
      //'#value' => $theme_key // core hacked: removed
      '#value' => $theme // core hacked: added
    );
    $form[$key]['weight'] = array(
      '#type' => 'weight',
      '#default_value' => $block['weight'],
      '#delta' => $weight_delta,
    );
    $form[$key]['region'] = array(
      '#type' => 'select',
      '#default_value' => $block['region'],
      '#options' => $block_regions,
    );

    if ($throttle) {
      $form[$key]['throttle'] = array('#type' => 'checkbox', '#default_value' => isset($block['throttle']) ? $block['throttle'] : FALSE);
    }
    $form[$key]['configure'] = array('#value' => l(t('configure'), 'admin/build/block/configure/'. $block['module'] .'/'. $block['delta']));
    if ($block['module'] == 'block') {
      $form[$key]['delete'] = array('#value' => l(t('delete'), 'admin/build/block/delete/'. $block['delta']));
    }
  }

  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Save blocks'),
  );

  return $form;
}

function template_preprocess_block_admin_display_form(&$variables) {
  global $theme_key;

  //$block_regions = system_region_list($theme_key); // core hacked: removed
  $block_regions = system_region_list($variables['form']['_theme']['#value']); // core hacked: added
  $variables['throttle'] = module_exists('throttle');
  $variables['block_regions'] = $block_regions + array(BLOCK_REGION_NONE => t('Disabled'));

  foreach ($block_regions as $key => $value) {
    // Highlight regions on page to provide visual reference.
    drupal_set_content($key, '<div class="block-region">'. $value .'</div>');
    // Initialize an empty array for the region.
    $variables['block_listing'][$key] = array();
  }

  // Initialize disabled blocks array.
  $variables['block_listing'][BLOCK_REGION_NONE] = array();

  // Set up to track previous region in loop.
  $last_region = '';
  foreach (element_children($variables['form']) as $i) {
    $block = &$variables['form'][$i];

    // Only take form elements that are blocks.
    if (isset($block['info'])) {
      // Fetch region for current block.
      $region = $block['region']['#default_value'];

      // Set special classes needed for table drag and drop.
      $variables['form'][$i]['region']['#attributes']['class'] = 'block-region-select block-region-'. $region;
      $variables['form'][$i]['weight']['#attributes']['class'] = 'block-weight block-weight-'. $region;

      $variables['block_listing'][$region][$i]->row_class = isset($block['#attributes']['class']) ? $block['#attributes']['class'] : '';
      $variables['block_listing'][$region][$i]->block_modified = isset($block['#attributes']['class']) && strpos($block['#attributes']['class'], 'block-modified') !== FALSE ? TRUE : FALSE;
      $variables['block_listing'][$region][$i]->block_title =  drupal_render($block['info']);
      $variables['block_listing'][$region][$i]->region_select = drupal_render($block['region']) . drupal_render($block['theme']);
      $variables['block_listing'][$region][$i]->weight_select = drupal_render($block['weight']);
      $variables['block_listing'][$region][$i]->throttle_check = $variables['throttle'] ? drupal_render($block['throttle']) : '';
      $variables['block_listing'][$region][$i]->configure_link = drupal_render($block['configure']);
      $variables['block_listing'][$region][$i]->delete_link = !empty($block['delete']) ? drupal_render($block['delete']) : '';
      $variables['block_listing'][$region][$i]->printed = FALSE;

      $last_region = $region;
    }
  }

  $variables['form_submit'] = drupal_render($variables['form']);
}