>>> [!note] Migrated issue <!-- Drupal.org comment --> <!-- Migrated from issue #3584884. --> Reported by: [abhisekmazumdar](https://www.drupal.org/user/3557964) Related to !1525 >>> <p>[Tracker]<br> <strong>Update Summary: </strong>[One-line status update for stakeholders]<br> <strong>Short Description: </strong>[One-line issue summary for stakeholders]<br> <strong>Check-in Date: </strong>MM/DD/YYYY<br> <em>Metadata is used by the <a href="https://www.drupalstarforge.ai/" title="AI Tracker">AI Tracker.</a> Docs and additional fields <a href="https://www.drupalstarforge.ai/ai-dashboard/docs" title="AI Issue Tracker Documentation">here</a>.</em><br> [/Tracker]</p> <h3 id="summary-problem-motivation">Problem/Motivation</h3> <p>When creating a new guardrail using either the <strong>RestrictToTopic</strong> or <strong>RegexpGuardrail</strong> plugins, the following PHP warnings appear in the logs:</p> <pre><pre>Warning: Undefined array key "invalid_topics_present_message" in Drupal\ai\Plugin\AiGuardrail\RestrictToTopic-&gt;buildConfigurationForm() (line 141)<br>Warning: Undefined array key "valid_topics_missing_message" in Drupal\ai\Plugin\AiGuardrail\RestrictToTopic-&gt;buildConfigurationForm() (line 155)<br>Warning: Undefined array key "violation_message" in Drupal\ai\Plugin\AiGuardrail\RegexpGuardrail-&gt;buildConfigurationForm() (line 128)</pre></pre><p>The <code>buildConfigurationForm()</code> methods in both plugins use the Elvis operator (<code>?:</code>) to access configuration keys that do not yet exist when a guardrail is first created. In PHP 8, this triggers an "Undefined array key" warning because <code>?:</code> evaluates the array access before applying the fallback &mdash; unlike <code>??</code>, which checks key existence first and suppresses the warning.</p> <h2>Steps to reproduce</h2> <ol> <li>Enable the AI module with guardrails support</li> <li>Navigate to create a new <strong>Regexp</strong> or <strong>RestrictToTopic</strong> guardrail</li> <li>Observe PHP warnings in the logs</li> </ol> <h2>Proposed resolution</h2> <p>Replace <code>?:</code> with <code>??</code> for the three affected keys so undefined array keys are handled safely:</p> <pre><pre>&lt;?php<br>// Before (triggers PHP warning when key is absent):<br>$this-&gt;configuration['violation_message'] ?: 'default message';<br><br>// After (null-safe, no warning):<br>$this-&gt;configuration['violation_message'] ?? 'default message';</pre></pre><p>The same change applies to <code>'invalid_topics_present_message'</code> and <code>'valid_topics_missing_message'</code> in <code>RestrictToTopic.php</code>.</p> <h2>Remaining tasks</h2> <ul> <li>Fix <code>RegexpGuardrail::buildConfigurationForm()</code> &mdash; <code>violation_message</code> key</li> <li>Fix <code>RestrictToTopic::buildConfigurationForm()</code> &mdash; <code>invalid_topics_present_message</code> and <code>valid_topics_missing_message</code> keys</li> </ul> <h2>User interface changes</h2> <p>None. The form renders and saves correctly &mdash; this is a warning cleanup only.</p> <h3 id="summary-ai-usage">AI usage (if applicable)</h3> <p>[ x ] AI Assisted Issue<br> This issue was generated with AI assistance, but was reviewed and refined by the creator.</p> <p>[ ] AI Assisted Code<br> This code was mainly generated by a human, with AI autocompleting or parts AI generated, but under full human supervision.</p> <p>[ ] AI Generated Code<br> This code was mainly generated by an AI with human guidance, and reviewed, tested, and refined by a human.</p> <p>[ ] Vibe Coded<br> This code was generated by an AI and has only been functionally tested.</p>