PHP 8.1 deprecation warning preg_split

Makes sense, thanks for posting!
Committed.

Since the commit of this patch, the search result highlighting integration tests of search_api_solr are failing.

Undefined array key "manu"
in
/home/runner/work/search_api_solr/search_api_solr/drupal/modules/contrib/search_api_solr/tests/src/Kernel/SearchApiSolrTechproductsTest.php:54

    // Test processor based highlighting.
    $query = $this->buildSearch('Technology', [], ['manu']);
    $results = $query->execute();
    $this->assertEquals(1, $results->getResultCount(), 'Search for »Technology« returned correct number of results.');
    /** @var \Drupal\search_api\Item\ItemInterface $result */
    foreach ($results as $result) {
      $this->assertStringContainsString('<strong>Technology</strong>', (string) $result->getExtraData('highlighted_fields', ['manu' => ['']])['manu'][0]);
      $this->assertEmpty($result->getExtraData('highlighted_keys', []));
      $this->assertEquals('… A-DATA <strong>Technology</strong> Inc. …', $result->getExcerpt());
    }

I just verified that reverting the patch lets the test pass again and "Technology" is highlighted again.

In case of "foreign" indexes like Search API Solr Document datasources or Drupal multisite searches, the value could be NULL. In this case the backend is responsible to modify the highlighted_fields extra data later if it allows to use the highlight processor.
Therefore, we must not remove the information about the field that "should" be highlighted at this point. Converting the value into an empty string is the backward compatible behaviour of this processor.

Thanks for noticing and posting a patch, and sorry for breaking your stuff again. ;)
Patch looks good – committed.
Thanks again!

Whelp, spoke too soon. Problem is actually that $value can be an object of type \Drupal\search_api\Plugin\search_api\data_type\value\TextValue at this point. While preg_split() doesn’t seem to have any problems accepting that as it’s second parameter (for some reason), it of course fails the is_string() check, letting its value be ignored.
Instead of all the above, let’s just explicitly cast $text to a string in highlightField(), which should also handle NULL values correctly.

Patch attached (plus interdiff compared to version before any of the patches here was committed), please test/review!

Seems to work, so: committed.

- Installing drupal/search_api (1.28.0): Extracting archive
- Applying patches for drupal/search_api
https://www.drupal.org/files/issues/2023-02-11/3323594-13--fix_bc_break_... → (3323594: PHP 8.1 deprecation warning preg_split)
Could not apply patch! Skipping. The error was: Cannot apply patch https://www.drupal.org/files/issues/2023-02-11/3323594-13--fix_bc_break_... →

Automatically closed - issue fixed for 2 weeks with no activity.