Error: Call to a member function getModel() on null
Closed, ResolvedPublicPRODUCTION ERROR
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Assigned To

Authored By

	Krinkle
	Sep 8 2021, 6:35 PM

Description

Error

mwversion: 1.37.0-wmf.21
reqId: f1967efd-a4a9-496d-87df-79f5132d9782
Find reqId in Logstash
Find normalized_message in Logstash

normalized_message

[{reqId}] {exception_url}   Error: Call to a member function getModel() on null

exception.trace

from /srv/mediawiki/php-1.37.0-wmf.21/includes/api/ApiEditPage.php(480)
#0 /srv/mediawiki/php-1.37.0-wmf.21/includes/api/ApiMain.php(1845): ApiEditPage->execute()
#1 /srv/mediawiki/php-1.37.0-wmf.21/includes/api/ApiMain.php(824): ApiMain->executeAction()
#2 /srv/mediawiki/php-1.37.0-wmf.21/includes/api/ApiMain.php(795): ApiMain->executeActionWithErrorHandling()
#3 /srv/mediawiki/php-1.37.0-wmf.21/api.php(90): ApiMain->execute()
#4 /srv/mediawiki/php-1.37.0-wmf.21/api.php(45): wfApiMain()
#5 /srv/mediawiki/w/api.php(3): require(string)
#6 {main}

Impact

Seen half a dozen time in the past few weeks.

Notes

Details

Related Changes in Gerrit:

	Subject	Repo	Branch	Lines +/-
	ApiEditPage: Harden content model mismatch checks	mediawiki/core	master	+10 -3

Customize query in gerrit

Event Timeline

Krinkle created this task.Sep 8 2021, 6:35 PM

Restricted Application added a subscriber: Aklapper. · View Herald TranscriptSep 8 2021, 6:35 PM

Krinkle moved this task from Untriaged to Sep 2021 on the Wikimedia-production-error board.Sep 8 2021, 6:35 PM

Krinkle added a project: MediaWiki-Page-editing.Sep 8 2021, 6:49 PM

Krinkle added a project: Unstewarded-production-error.

ApiEditPage.php

		// T255700: Ensure content models of the base content
		// and fetched revision remain the same before attempting to save.
		$editRevId = $requestArray['editRevId'] ?? false;
		$baseRev = $this->revisionLookup->getRevisionByTitle( $titleObj, $editRevId );
		$baseContentModel = $baseRev
			? $baseRev->getContent( SlotRecord::MAIN )->getModel()
			: $pageObj->getContentModel();

getContent( SlotRecord::MAIN ) is documented to return null, if the content is not visible for the current user.

When setting baserevid of action=edit to a revision id with revision deleted content (it could only non-current ones), it fails.
The audience of the getContent calll is public, which means for sysop it is not possible to use the revision deleted content as base rev, while index.php allows