https://weaponofmusicaldefense.com/index.php?action=history&feed=atom&title=DynamicPageList3_pagelinks_compatibility_fixDynamicPageList3 pagelinks compatibility fix - Revision history2026-06-11T13:10:06ZRevision history for this page on the wikiMediaWiki 1.43.1https://weaponofmusicaldefense.com/index.php?title=DynamicPageList3_pagelinks_compatibility_fix&diff=2205&oldid=prevMember005: Document problems with upgrading DPL2026-06-11T09:51:42Z<p>Document problems with upgrading DPL</p>
<p><b>New page</b></p><div>= Production remediation log: DynamicPageList3 pagelinks compatibility fix =<br />
''Date: 2026-06-11''<br />
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''Environment: production (<code>weaponofmusicaldefense.com</code>) and dev mirror (<code>dev.weaponofmusicaldefense.com</code>)''<br />
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== Summary ==<br />
After cutover to the upgraded MediaWiki stack, many content pages that include DynamicPageList3 (DPL) output began failing with <code>Wikimedia\Rdbms\DBQueryError</code> (HTTP 500).<br />
The failure was caused by DPL building <code>pagelinks</code> queries with assumptions incompatible with the active links schema.<br />
A targeted compatibility patch was applied in DPL <code>Query.php</code>, then propagated to dev.<br />
Affected pages now render normally (HTTP 200), with no immediate recurrence in recent logs.<br />
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== Problem observed ==<br />
* Affected behavior:<br />
** page view returned HTTP 500<br />
** <code>?action=edit</code> still returned 200 and showed page source<br />
* Representative failing pages:<br />
** <code>https://weaponofmusicaldefense.com/thelibrary/Winston_Churchill</code><br />
** <code>https://weaponofmusicaldefense.com/thelibrary/Hugh_Fitzgerald</code><br />
** <code>https://weaponofmusicaldefense.com/thelibrary/Appeasement</code><br />
* Error signatures observed during diagnosis:<br />
** <code>Unknown column 'pl.pl_title' in 'field list'</code><br />
** <code>Unknown column 'pl.pl_target_id' in 'on clause'</code><br />
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[upgrades]<br />
== Root cause ==<br />
DPL query construction in <code>DynamicPageList3/includes/Query.php</code> used <code>pagelinks</code> title/namespace assumptions that are not always valid after MediaWiki links schema migration.<br />
In the upgraded schema, <code>pagelinks</code> may reference <code>linktarget</code> via <code>pl_target_id</code> rather than storing <code>pl_namespace</code>/<code>pl_title</code> directly for the query path DPL was building.<br />
Additionally, one generated SQL shape mixed join styles in a way that caused alias scoping issues, producing an invalid <code>ON</code> clause reference.<br />
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== Patch applied ==<br />
Patched methods:<br />
* <code>_linksto(...)</code><br />
* <code>_notlinksto(...)</code><br />
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Key compatibility changes:<br />
# Use MediaWiki links migration API to discover correct title fields at runtime:<br />
#* <code>MediaWikiServices::getInstance()->getLinksMigration()->getTitleFields('pagelinks')</code><br />
# Detect when query fields are <code>lt_*</code> and therefore require <code>linktarget</code>:<br />
#* <code>needsLinkTarget = strpos($nsField, 'lt_') === 0 || strpos($titleField, 'lt_') === 0</code><br />
# In <code>_linksto(...)</code>, when <code>needsLinkTarget</code> is true:<br />
#* add <code>linktarget</code> table alias <code>lt</code><br />
#* relate rows via <code>lt.lt_id = pl.pl_target_id</code><br />
#* use <code>lt.&lt;field&gt;</code> expressions for namespace/title comparisons and selected aliases (<code>sel_ns</code>, <code>sel_title</code>)<br />
# In <code>_notlinksto(...)</code>, when <code>needsLinkTarget</code> is true:<br />
#* use a subquery joining <code>pagelinks pl_sub</code> to <code>linktarget lt_sub</code> on <code>lt_sub.lt_id = pl_sub.pl_target_id</code><br />
#* evaluate title/namespace filters against <code>lt_sub.&lt;field&gt;</code><br />
# Correct SQL scoping issue in <code>_linksto(...)</code> by applying the <code>lt</code>↔<code>pl</code> relation as a <code>WHERE</code> condition (<code>addWhere('lt.lt_id = pl.pl_target_id')</code>) instead of the prior problematic join-form expression.<br />
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== Files changed ==<br />
* <code>mw_data_staging/extensions/DynamicPageList3/includes/Query.php</code> (production-served tree)<br />
* <code>mw_data/extensions/DynamicPageList3/includes/Query.php</code> (dev tree mirror)<br />
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== Why this patch was needed ==<br />
Without this patch, DPL generated SQL that referenced columns/aliases not valid for the active links schema and join shape, causing fatal query exceptions and site-visible HTTP 500s on pages using DPL link filters.<br />
The patch makes DPL schema-aware at runtime through <code>LinksMigration</code> and uses SQL forms compatible with the current schema.<br />
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== Validation ==<br />
* Re-tested previously failing production pages: now HTTP 200.<br />
* Re-tested corresponding dev pages: now HTTP 200.<br />
* Confirmed production and dev DPL <code>Query.php</code> are synchronized.<br />
* Recent production log scan after patch showed no new <code>DBQueryError</code> spikes for this incident pattern.<br />
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== Follow-up recommendations ==<br />
* Monitor for additional DPL code paths that may still assume legacy/new-incompatible <code>pagelinks</code> field usage (for example in related link-filter parameters).<br />
* Upstream this compatibility patch (or move to an upstream DPL release containing equivalent links-migration support) to reduce local patch drift.<br />
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[[Category:upgrades]]</div>Member005