- Patch #635212 by sun, David_Rothstein, ryandekker, tstoeckler: fallback format is not configurable.

modules/filter/filter.admin.inc

@@ -322,12 +322,25 @@ function filter_admin_format_form_submit($form, &$form_state) {
 function filter_admin_delete($form, &$form_state, $format) {
   $form['#format'] = $format;
 
+  $fallback_options = array();
+  foreach (filter_formats() as $id => $fallback_format) {
+    if ($id != $format->format) {
+      $fallback_options[$id] = $fallback_format->name;
+    }
+  }
+  $form['fallback'] = array(
+    '#type' => 'select',
+    '#title' => t('Replacement text format'),
+    '#options' => $fallback_options,
+    '#default_value' => filter_fallback_format(),
+    '#description' => t('Content assigned to the deleted text format will be reassigned to the chosen one.'),
+  );
+
   return confirm_form($form,
     t('Are you sure you want to delete the text format %format?', array('%format' => $format->name)),
     'admin/config/content/formats',
-    t('If you have any content left in this text format, it will be switched to the %fallback text format. This action cannot be undone.', array('%fallback' => filter_fallback_format_title())),
-    t('Delete'),
-    t('Cancel')
+    NULL,
+    t('Delete')
   );
 }
 
@@ -336,7 +349,7 @@ function filter_admin_delete($form, &$form_state, $format) {
  */
 function filter_admin_delete_submit($form, &$form_state) {
   $format = $form['#format'];
-  filter_format_delete($format);
+  filter_format_delete($format, $form_state['values']['fallback']);
   drupal_set_message(t('Deleted text format %format.', array('%format' => $format->name)));
 
   $form_state['redirect'] = 'admin/config/content/formats';

modules/filter/filter.api.php

@@ -235,15 +235,15 @@ function hook_filter_format_update($format) {
 /**
  * Perform actions when a text format has been deleted.
  *
- * It is recommended for modules to implement this hook, when they store
- * references to text formats to replace existing references to the deleted
- * text format with the fallback format.
+ * All modules storing references to text formats have to implement this hook.
+ *
+ * When a text format is deleted, all content that previously had that format
+ * assigned needs to be switched to the passed fallback format.
  *
  * @param $format
  *   The format object of the format being deleted.
  * @param $fallback
- *   The format object of the site's fallback format, which is always available
- *   to all users.
+ *   The format object of the format to use as replacement.
  *
  * @see hook_filter_format_insert()
  * @see hook_filter_format_update()

modules/filter/filter.module

@@ -260,8 +260,12 @@ function filter_format_save(&$format) {
  *
  * @param $format
  *   The text format object to be deleted.
+ * @param $fallback_id
+ *   (optional) The ID of the text format to use to reassign content that is
+ *   currently using $format. If omitted, the currently stored
+ *   filter_fallback_format() is used.
  */
-function filter_format_delete($format) {
+function filter_format_delete($format, $fallback_id = NULL) {
   db_delete('filter_format')
     ->condition('format', $format->format)
     ->execute();
@@ -270,7 +274,10 @@ function filter_format_delete($format) {
     ->execute();
 
   // Allow modules to react on text format deletion.
-  $fallback = filter_format_load(filter_fallback_format());
+  if (empty($fallback_id)) {
+    $fallback_id = filter_fallback_format();
+  }
+  $fallback = filter_format_load($fallback_id);
   module_invoke_all('filter_format_delete', $format, $fallback);
 
   filter_formats_reset();
@@ -488,11 +495,6 @@ function filter_default_format($account = NULL) {
  * format is initialized to output plain text. Installation profiles and site
  * administrators have the freedom to configure it further.
  *
- * When a text format is deleted, all content that previously had that format
- * assigned should be switched to the fallback format. To facilitate this,
- * Drupal passes in the fallback format object as one of the parameters of
- * hook_filter_format_delete().
- *
  * Note that the fallback format is completely distinct from the default
  * format, which differs per user and is simply the first format which that
  * user has access to. The default and fallback formats are only guaranteed to