Line 79 of RouteCompiler has this line:
return preg_replace('#\{\w+\}#', '%', $path);
This triggers a deprecation warning when running on PHP 8.1:
Deprecated function: preg_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated in Drupal\Core\Routing\RouteCompiler::getPatternOutline() (line 77 of core/lib/Drupal/Core/Routing/RouteCompiler.php).
Using PHP 8.1
Needs work
9.5
Used to track the progress of issues reviewed by the Drupal Needs Review Queue Initiative.
The change is currently missing an automated test that fails when run with the original code, and succeeds when the bug has been fixed.
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
This issue is being reviewed by the kind folks in Slack, #needs-review-queue-initiative. We are working to keep the size of Needs Review queue [2700+ issues] to around 400 (1 month or less), following Review a patch or merge request → as a guide.
The issue summary could use steps for how you triggered this. While it may be good to fix it here we want to know what triggered it in the first place.
As a bug it will need a test case too