"Add content" (/node/add) gives an error

I think I found the culprit. As I'm running a multi-lingual site, the page is handles by i18n_node_add_page instead of node_add_page. And the former doesn't appear to be ported to Backdrop. This is the code of i18n_node_add_page:

<?php
function i18n_node_add_page() {
    $item = menu_get_item();
    $content = system_admin_menu_block($item);
// ;...;
}

This is the only place left in the entire Backdrop codebase that uses this approach, apart from a few places in system.admin.inc. system_admin_menu_block is a function that looks up the system menu plus routes for thethe administration backend in the databse. And that returns an empty array.

This is what node_add_page looks like:

<?php
function node_add_page() {
  $content = array();
  // Only use node types to which the user has access.
  foreach (node_type_get_types() as $node_type) {
    if (node_access('create', $node_type->type)) {
      $href_url_friendly = str_replace('_', '-', $node_type->type);
      $content[$node_type->type] = array(
        'title' => t($node_type->name),
        'href'=>'node/add/' . $href_url_friendly,
        'localized_options' => array('html' => FALSE),
        'description' => t($node_type->description),
      );
    }
  }
// ...
}

and this is how it looked in Drupal 7:

<?php
 function node_add_page() {
  $item = menu_get_item();
  $content = system_admin_menu_block($item);
  // ...
}

That looks oddly familiar.

If I replace the codde of i18n_node_add_page with the new code opf node_add_page. the page just works. Perhaps it needs a few more tweaks, but the titles are translated and everything. I'm not even sure why i18n_node_add_page contained pretty much a copy of node_add_page, perhaps it should just point to node_adD_page instead, but I couldn't get that to worke because the source file from node that contains the function wasn't loaded.

I think I found the culprit. As I'm running a multi-lingual site, the page is handles by i18n_node_add_page instead of node_add_page. And the former doesn't appear to be ported to Backdrop. This is the code of i18n_node_add_page:

<?php
function i18n_node_add_page() {
    $item = menu_get_item();
    $content = system_admin_menu_block($item);
// ;...;
}

This is the only place left in the entire Backdrop codebase that uses this approach, apart from a few places in system.admin.inc. system_admin_menu_block is a function that looks up the system menu plus routes for thethe administration backend in the databse. And that returns an empty array.

This is what node_add_page looks like:

<?php
function node_add_page() {
  $content = array();
  // Only use node types to which the user has access.
  foreach (node_type_get_types() as $node_type) {
    if (node_access('create', $node_type->type)) {
      $href_url_friendly = str_replace('_', '-', $node_type->type);
      $content[$node_type->type] = array(
        'title' => t($node_type->name),
        'href'=>'node/add/' . $href_url_friendly,
        'localized_options' => array('html' => FALSE),
        'description' => t($node_type->description),
      );
    }
  }
// ...
}

and this is how it looked in Drupal 7:

<?php
 function node_add_page() {
  $item = menu_get_item();
  $content = system_admin_menu_block($item);
  // ...
}

That looks oddly familiar.

If I replace the codde of i18n_node_add_page with the new code opf node_add_page. the page just works. Perhaps it needs a few more tweaks, but the titles are translated and everything.