As of 2.0.3: "Warning: array_key_exists(): The first argument should be either a string or an integer" when encountering page titled via TranslatableMarkup

This is a super helpful start Max! Thank you.

I too am looking into this. A very similar problem to to this as I am going from php 7.4 to 8.0.13 (Acquia Hosting)
Line 492 changing it to include a check for string or int:
`if (!empty($title) && (is_string($title) || is_numeric($title)) && array_key_exists($title, $replacedTitles)) {`
fixes the problem for me. This error is related to TMGMT returning an object instead of a string for `$entity->label()` on line 490

For TMGMT, you should be able to update your TMGMT to fix the problem, but also our code should be robust enough not to get warnings when other modules have a bug.

Hi Greg! Thanks for your quick response. I am encountering this issue not as a warning but as a error on administration pages using breadcrumbs. (specifically when requesting translation jobs).

Turning off the breadcrumb setting `use on admin pages` is not possible for us, but is a 'no-code' work around that might work for others.

With respect to your comment, TMGMT is fully updated to my knowledge and the error occurs.
Using

• Drupal 9.4.1
• php 8.0.13 (Acquia hosting)
• The most current TMGMT to my knowledge `^1.13`

* Additional edit: forgot to mark my patch as needing review

Hrm, ok this may be a different page in tmgmt, here's the recent issue for that:

https://www.drupal.org/project/tmgmt/issues/3291991

There should be code for when a title is an object instead of a string... Not sure why it's not working in this case.

This one is working for me on 2.0.3, and its a pretty simple change. Hope it can help someone else.

looks good. Can you open the change as a merge request?

Created MR of patch #12.

Patch from #12 fixed our problem.
Before this patch we encountered the same error.

First we used the patch from #7. But our team thinks #12 is a nicer solution.

Merge request seems to look fine.

I see something on this merge request that looks wrong.
From https://git.drupalcode.org/project/easy_breadcrumb/-/blob/52971f62f5f114...

if ($entity instanceof EntityInterface && $entity->hasLinkTemplate('canonical')) {
  $title = $this->normalizeText($this->getTitleString($route_request, $route_match, $replacedTitles));
  // Add this entity's cacheability metadata.
  $breadcrumb->addCacheableDependency($entity);
  $title = (string) $entity->label();
  // If the title is to be replaced replaces the title.
  if (!empty($title) && array_key_exists($title, $replacedTitles)) {
    $title = $replacedTitles[$title];
  }
  if ($title && $this->config->get(EasyBreadcrumbConstants::TRUNCATOR_MODE)) {
    $title = $this->truncator($title);
  }
  break;
}

$title first gets set on line 501:

$title = $this->normalizeText($this->getTitleString($route_request, $route_match, $replacedTitles));

But then gets overwritten on line 504:

$title = (string) $entity->label();

So line 501 (with the normalizeText() call) looks redundant. That, or a check is missing that makes the right title to be picked.

I agree with MegaChriz that it looks like there went something wrong in the merge, but I think the
$title = (string) $entity->label();
is the redundant one, since the getTitleString()-method also considers Breadcrumb-Overrides (which would be overridden by the entity-label afterwards.