Ensure uninstalling a module providing a checkout pane doesn't remove all checkout flows.

Probably because of this code:

  public function calculateDependencies() {
    $dependencies = parent::calculateDependencies();
    // Merge-in the pane dependencies.
    foreach ($this->getPanes() as $pane) {
      foreach ($pane->calculateDependencies() as $dependency_type => $list) {
        foreach ($list as $name) {
          $dependencies[$dependency_type][] = $name;
        }
      }
    }

    return $dependencies;
  }

present in CheckoutFlowWithPanesBase::calculateDependencies().

That adds dependencies on all the checkout panes.

This feels like a bug.

Try commenting the code in calculateDependencies()? (that is CheckoutFlowWithPanesBase::calculateDependencies() and see if this makes a difference.

I managed to write a failing test, but I've failed to fix the issue itself for now.

I started adding the following to CheckoutFlow:

  /**
   * {@inheritdoc}
   */
  public function onDependencyRemoval(array $dependencies) {
    $changed = parent::onDependencyRemoval($dependencies);

    // For checkout flows with panes, ensure panes provided by the module being
    // uninstalled are removed from the configuration.
    if ($this->getPlugin() instanceof CheckoutFlowWithPanesInterface) {
      $uninstalled_modules = $dependencies['module'];
      $panes_to_remove = [];
      /** @var \Drupal\commerce_checkout\CheckoutPaneManager $pane_manager */
      $pane_manager = \Drupal::service('plugin.manager.commerce_checkout_pane');

      foreach ($pane_manager->getDefinitions() as $definition) {
        if (in_array($definition['provider'], $uninstalled_modules)) {
          $panes_to_remove[$definition['id']] = $definition['id'];
        }
      }

      if ($panes_to_remove) {
        $this->configuration['panes'] = array_diff_key($this->configuration['panes'], $panes_to_remove);
        $changed = TRUE;
      }
    }

    return $changed;
  }

But that doesn't seem to do the trick as when calculateDepencies() is then called, the dependency is re-added.

@zenimagine: No, not yet, the test i wrote demonstrates the problem, but haven't managed to fix it yet.

The attached patch should do the trick, hopefully!

I didn't upload the right patch in #13, but the changes done since aren't altering the logic. I wrote a functional test proving the logic works, and just to be sure, I just retested this myself manually.

The test configures a pane from a module that is then uninstalled, the test confirms the checkout flow still exists after uninstalling the module, and the configuration is correctly updated (i.e the pane that was provided by the module is removed from the checkout flow configuration).

hm... I'm really not sure what to do then, the test I wrote is testing exactly that, and I manually tested this as well, and the checkout flow remained.

Are the checkout flows provided by the module you're uninstalling as well?

Yes, I tested with other checkout flows, tried it again just now.

I created a custom checkout flow, saved it with the custom checkout pane, then uninstalled the module providing the checkout pane, and the checkout flow remained.

I went ahead and committed a fix since I was able to reproduce the bug manually and wrote a failing test that no longer fails with the fix.