"Delete redirects defined in the spreadsheet" misses to remove leading slash normalization

This is the method where the magic should happen:

/**
   * Loads the Redirects to delete and redirects to the Deletion confirm form.
   *
   * @param \Drupal\Core\Form\FormStateInterface $form_state
   *   The current state of the form.
   *
   * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
   * @throws \Drupal\Component\Plugin\Exception\PluginNotFoundException
   * @throws \Drupal\Core\TempStore\TempStoreException
   * @throws \Drupal\migrate\MigrateException
   * @throws \League\Csv\Exception
   */
  protected function deleteRedirectData(FormStateInterface $form_state) {
    $redirects = $this->redirectsToDelete();
    $this->privateTempStore->set($this->currentUser->id(), $redirects);
    $options = [
      'query' => $this->getDestinationArray(),
    ];
    $form_state->setRedirect('entity.redirect.multiple_delete_confirm', [], $options);
  }

but in my described case (deleting the same records from .csv as imported before) $redirects = $this->redirectsToDelete(); simply returns an empty array.

So I'm redirected back to the redirect form!

Yes I was right in #2. The current implementation misses the leading slash in the normalization, which leads to malfunction due to different hashes.

I created a core issue to decide if that's something to improve in Core: 🐛 Should UrlHelper::parse() unify the leading slash for local URLs? Active
Still we need to unify it here, as I don't think there will be a related change in core soon.

I'll prepare a MR.

LGTM! RTBC+1.

Thanks @Grevil!

The root cause should be fixed here: 📌 Public method Redirect::generateHash() should unify path before generating the hash Active (and eventually in core: 🐛 Should UrlHelper::parse() unify the leading slash for local URLs? Active )

Until that, this fix should solve it.