Comments + entity->uri issue

@sylus
Can you try this patch and let me know if it solves your problem?

We discovered something similar i think. When you add a field (plain not formatted) in a paragraphs type and in Managed display check Link to the Paragraph then you get similar error massage about canonical link template missing.

Not sure if this is the right approach but it solves our problem...
With this you can access a paragraph on paragraphs/{some_id} witch might not be desired behavior.

I just noticed the other related issue. Yea I guess this needs to be fixed in core, this probably wont be committed but here it is if someone needs it to avoid the nasty error.

This came up before, but I'm not conviced about just adding a default link. that will display that paragraph on /paragraph/1 but that makes no sense.

The only thing that might make sense is redirecting that to the node the paragraph is shown, but not sure about the.

The image issue also already has a duplicate somewhere.

I still think that code should not hardcode the assumption that there is a canonical link template although core now documents that somehow now.

@Berdir if implementing such a "workaround" would be the right approach, then core should be cristal clear and require all entities to provide such a route. If not, we are doing the right thing to not provide it.

There is a related issue where the core quick edit requires each entity to provide a form and only providing those routes solves half of the integration.

What we do with Entity Reference Revision, is defining new integrity constrains and extend the concepts of the entity subsystem. We try to be transparent, but as core is not aware if composite relationship concept, we have limitations. Combined with other dimensions where core has limitations (multilingual, revisions, recently workflows / workspaces) the integration complexity is gaining crazy complexity.

Whatever silently assumes wrongly there is always such an URI is technically "incompatible" with Peargraphs. ;-)

To workaround the problem for the impatient people, adding a extra project / module that defines the routes could be the best approach. The workaround with a redirect route has other faux impacts, including code that determine an entity "canonical" by using "==" comparing the route with the entity uri.

Alternatively, we could try to return an uri to the host entity with an anchor address to the DOM id. Not sure if drupal likes these kind of canonicals.

Patch #6 works for me.

But i agree that redirect to "/paragraph/{ID}" is quite annoying.

Like i need something now, i made this small code.

use Symfony\Component\HttpFoundation\RedirectResponse;
use Drupal\Core\Url;
function module_comment_insert(Drupal\Core\Entity\EntityInterface $comment) {
  $content_comment = $comment->getCommentedEntity();
  $content_comment_type = $content_comment->getType();
  
  // If comment is set on my custom paragraph
  if($content_comment_type == 'prestation') {
    // I redirect to parent entity
    $url = Url::fromRoute('entity.node.canonical', ['node' => $content_comment->getParentEntity()->id()])->toString();
    $response = new RedirectResponse($url);
    $response->send();
  }
}

I have re-rolled the #06 patch with the latest version.

I created a patch for the Drupal core that should solve this issue. It looks at the parent entity of the paragraph if the URI callback is not valid.
Paragraphs with comment field results in UndefinedLinkTemplateException.

Please review.

Patch re-rolled.

Seems like we can dupe on #3238515: No link template 'canonical' found for the 'paragraph' entity type

Well, that is closed, and so should this issue. It's a duplicate of the core issue that you commented on as well, because paragraphs module isn't going to accommodate comment.module by adding this. As others commented, having the paragraph then on its own page is weird.

What you could do as a workaround in a project is add a canonical link template that redirects back to the host node of the paragraph.

One potential solution is using Entity Bundle Classes, add your own bundle class Comment entity, and override getCommentedEntity() or whichever method, rewriting to the paragraph parent.

When a page displays a fatal error, it is really hard to believe is a Fixed issue. It's should fix on the Paragraph module or the Comment module. If the user is not allowed to use Paragraph and Comment together, it should be disabled before the user adds the Comment field to the Paragraph.
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