Cannot find route error

Same issue here! Any plans to finally fix this?

Okay, let's bring some light into this issue!

search.view_node_search route is the default route created for the "Content" search from Drupal core installation.
search.view is the route of the general search page, while
search.view_{MACHINE_NAME} is the route of the search page type.

So you have to enter "node_search" as machine name of your new search page to replace the core node search!

The logic can be found in the Core search module in the core/modules/search/src/Routing/SearchPageRoutes.php:

/**
   * Returns an array of route objects.
   *
   * @return \Symfony\Component\Routing\Route[]
   *   An array of route objects.
   */
  public function routes() {
    $routes = [];
    // @todo Decide if /search should continue to redirect to /search/$default,
    //   or just perform the appropriate search.
    if ($default_page = $this->searchPageRepository->getDefaultSearchPage()) {
      $routes['search.view'] = new Route(
        '/search',
        [
          '_controller' => 'Drupal\search\Controller\SearchController::redirectSearchPage',
          '_title' => 'Search',
          'entity' => $default_page,
        ],
        [
          '_entity_access' => 'entity.view',
          '_permission' => 'search content',
        ],
        [
          'parameters' => [
            'entity' => [
              'type' => 'entity:search_page',
            ],
          ],
        ]
      );
    }
    $active_pages = $this->searchPageRepository->getActiveSearchPages();
    foreach ($active_pages as $entity_id => $entity) {
      $routes["search.view_$entity_id"] = new Route(
        '/search/' . $entity->getPath(),
        [
          '_controller' => 'Drupal\search\Controller\SearchController::view',
          '_title' => 'Search',
          'entity' => $entity_id,
        ],
        [
          '_entity_access' => 'entity.view',
          '_permission' => 'search content',
        ],
        [
          'parameters' => [
            'entity' => [
              'type' => 'entity:search_page',
            ],
          ],
        ]
      );
[...]

Some themes simply seem to rely on {{ path('search.view_node_search') }} being present, so this module should at least document this edge case and how to solve it.

After uninstalling the module, you have to re-import the core node_search search or add it manually with exactly that module name!

Hooray!

I'm closing this with it being worked at in 🐛 Route does not exist Active on the supported 3.x branch. Also bearing in mind that I still believe this to be a Core bug as per #10.