PathBasedBreadcrumbBuilder needs to be able to exclude pointless paths

          $title = $this->titleResolver->getTitle($route_request, $route_match->getRouteObject());
          if (!isset($title)) {
            // Fallback to using the raw path component as the title if the
            // route is missing a _title or _title_callback attribute.
            $title = str_replace(['-', '_'], ' ', Unicode::ucfirst(end($path_elements)));
          }

Well this fallback is suppose to prevent empty titles but it's not.

Something like this would make the fallback work as expected.

Locally ran testEmptyStringStaticTitle without the fix and it passes. Shouldn't this fail? If not would this be out of scope as it's not testing the bug?

@smustgrave yeah that's because of how the code currently works. The test that fails is \Drupal\Tests\Core\Controller\TitleResolverTest::testDynamicTitle(). I added \Drupal\Tests\Core\Controller\TitleResolverTest::testEmptyStringStaticTitle() to show that currently the way dynamic and static title behave is inconsistent.

I've added yet another test to prove consistent behaviour - testing a route with absolutely no title - ie. no callback or _title.

So if we do steps to reproduce on 🐛 [PP-1] Empty breadcrumb at node/add and node/add/{content_type} when frontpage view is enabled Postponed you get a breadcrumb of Home >> Node - it creates a title of Node based on the path. So this code...

          $title = $this->titleResolver->getTitle($route_request, $route_match->getRouteObject());
          if (!isset($title)) {
            // Fallback to using the raw path component as the title if the
            // route is missing a _title or _title_callback attribute.
            $title = str_replace(['-', '_'], ' ', Unicode::ucfirst(end($path_elements)));
          }

Is working as expected. BUT for me this code is pretty interesting if you consider multilingual sites. Paths in Drupal especially the admin interface will be English so I'm not convinced that this behaviour is correct. Another option would be to omit pages without titles from breadcrumbs.

The last submitted patch, 5: 3344200-5.test-only.patch, failed testing. View results →

+++ b/core/lib/Drupal/Core/Controller/TitleResolver.php
@@ -76,6 +77,12 @@ public function getTitle(Request $request, Route $route) {
       // Fall back to a static string from the route.
       $route_title = $this->t($title, $args, $options);
...
+    if ($route_title === '' || ($route_title instanceof TranslatableMarkup && $route_title->getUntranslatedString() === '')) {
+      return NULL;

Maybe better to check for instance of before converting value to string value object?

@andypost === does not convert anything - see https://3v4l.org/cWOn9

Thanks 👍 then only #6 a question, maybe follow-up to discuss what to do with empty title for breadcrumbs, for example instead of omitting we can display elepsis character to make it navigable

Yeah I also find it interesting that "Batch" and "Node" start appearing with the relevant patch(s) applied. Agree with comment #6, and I guess we're only now seeing the true result of what that part of the Breadcrumb Builder ends up outputting, which is technically better than a weird looking empty breadcrumb part.

Technically the patch works as expected, so happy to RTBC this.

But as noted we should revisit that part of the Breadcrumb Builder to determine if that is actually the behaviour we want.

Discussed with @catch and @larowlan - there is consensus that rather than using the path we should skip the link - like we do for items that a user does not have access too.

For #11

Here's an implementation that skips paths with no titles. We'll need a change to update this.

Here's a screenshot of visiting /batch/11

Breadcrumb is not rendering empty crumb, example Home > [blank]

Moving to NW for the change record.