>>> [!note] Migrated issue <!-- Drupal.org comment --> <!-- Migrated from issue #3592122. --> Reported by: [mably](https://www.drupal.org/user/3375160) Related to !14 >>> <p><strong>Problem/Motivation</strong></p> <p>On an auto chain that captures the <code>php</code> channel, brand-new rows display <code>(purged)</code> for Message and User immediately on creation, with no purge segment involved. The row's <code>context_transient</code> column is an empty string while a non-empty <code>context_transient_hash</code> is stored, so the entries viewer treats the row as retention-purged. The forensic envelope (uid, ip, request_uri, message_template) is silently lost.</p> <p><strong>Steps to reproduce</strong></p> <ul> <li>Enable an auto chain (mode: auto) whose channels include <code>php</code>.</li> <li>Cause any PHP notice or deprecation while an object graph with circular references is on the stack. core hands the php logger the raw <code>debug_backtrace()</code>, and e.g. a Views View and its executable reference each other.</li> <li>Open the entries list: the new php row shows <code>(purged)</code>, dated seconds ago.</li> <li>Deterministic repro: call <code>AuditTrailChainWriter::encodeBucket()</code> with a context whose value contains a circular reference; it returns an empty string and <code>json_last_error_msg()</code> is "Recursion detected".</li> </ul> <p><strong>Root cause</strong></p> <p>core <code>includes/errors.inc</code> hands the php logger the raw <code>debug_backtrace()</code> array under the <code>backtrace</code> context key; those frames hold real call args, including circular object graphs (a View and its executable reference each other).</p> <p><code>AuditTrailLogger</code> copies the whole context into the transient bucket and strips only <code>exception</code>, not <code>backtrace</code>. <code>AuditTrailChainWriter::encodeBucket()</code> then does <code>(string) json_encode(...)</code>; json_encode returns FALSE on the recursion, and FALSE casts to an empty string. The writer then sha256-hashes that empty string, storing a non-empty <code>context_transient_hash</code> over empty content. The viewer reads "empty transient + non-empty hash" as purged.</p> <p>Valid UTF-8 content is not involved and is unaffected.</p> <p><strong>Proposed resolution</strong></p> <ul> <li><code>AuditTrailLogger</code>: also unset <code>backtrace</code> alongside <code>exception</code> before stamping the transient bucket. The raw backtrace is a recursion-prone object graph; <code>@backtrace_string</code> already carries a forensic string.</li> <li><code>AuditTrailChainWriter::encodeBucket()</code>: add <code>JSON_PARTIAL_OUTPUT_ON_ERROR</code> so an un-encodable value degrades to a partial document instead of FALSE, and throw when json_encode still fails so the logger breadcrumb fires instead of writing an empty bucket.</li> <li><code>AuditTrailChainWriter</code>: normalize an empty-string transient to NULL before hashing, so an empty bucket is never indistinguishable from a purged one.</li> </ul> <p><strong>Remaining tasks</strong></p> <ul> <li>Regression test: log an event whose context holds a circular reference; assert the transient bucket is non-empty and carries the message, the chain verifies clean, and the viewer renders the message rather than <code>(purged)</code>.</li> </ul>