Panels IPE Loses Route Parameter Contexts

I wonder if this is due to the gathered contexts logic in PanelsBlockConfigureFormBase::buildForm() that does not appear in PanelsIPEBlockPluginForm:

    $contexts = $this->variantPlugin->getPattern()->getDefaultContexts($this->tempstore, $this->getTempstoreId(), $machine_name);
    $this->variantPlugin->setContexts($contexts);
    $form_state->setTemporaryValue('gathered_contexts', $contexts);

Do you have an example of a Block Plugin in Panels IPE that is throwing an error or losing Context?

Obviously the preferred solution here is to consolidate our form logic so that PanelsIPEBlockPluginForm extends PanelsBlockConfigureFormBase, but I'm not sure if a change that big can get in before the beta5 release. If I can quickly fix this before then, I'd like to!

It may also be worth merging this issue with #2636472: Load context for page that IPE is editing, rather than AJAX or form route.

@EclipseGc I think a good first step would be to refactor all IPE forms to extend the forms written for the backend editor. Do you think that would help to resolve this issue?

If so - I can review some code next week and open a new issue for this.

Easy replication steps (for my benefit):

1. Install the standard profile
2. Panelize the "Basic Page" Content Type
3. Use IPE on a Basic Page, open the "Content" category
4. See the "Image" entity_field block, even though there is no image field for Basic Pages.

Following the same replication steps as #8, but using the default editor introduced by #2664682: Implement admin UI for editing Panelizer defaults, I see the same issue. I've attached a screenshot of the wizard editor for the "Basic Page" type, which also lists all entity_field blocks regardless of the Content Type.

I'd need to see a working example of what IPE is supposed to do before digging deeper.

Punting to the next beta.

Fixed in #3465159: Error: Call to a member function getParameter() on null in Drupal\panels_ipe\Form\PanelsIPEBlockPluginForm->getContextsForPath() (line 505 of /var/www/docroot/modules/contrib/panels/panels_ipe/src/Form/PanelsIPEBlockPluginForm.php)? being hopeful... and triaging queue.