PHP Warning: DOMNode::appendChild(): Document Fragment is empty
Closed, ResolvedPublicPRODUCTION ERROR
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	Zabe
	Oct 15 2025, 8:54 AM

Description

Error

service.version: 1.45.0-wmf.23
timestamp: 2025-10-15T08:48:27.772Z
labels.phpversion: 8.1.33
trace.id: 57b07c06-8780-49e4-88b0-5ecf7fa1e119
Find trace.id in Logstash

labels.normalized_message

[{reqId}] {exception_url}   PHP Warning: DOMNode::appendChild(): Document Fragment is empty

Frame	Location	Call
from	/srv/mediawiki/php-1.45.0-wmf.23/includes/OutputTransform/ContentDOMTransformStage.php(70)
#0	[internal function]	MediaWiki\Exception\MWExceptionHandler::handleError(int, string, string, int)
#1	/srv/mediawiki/php-1.45.0-wmf.23/includes/OutputTransform/ContentDOMTransformStage.php(70)	DOMNode->appendChild(Wikimedia\Parsoid\DOM\DocumentFragment)
#2	/srv/mediawiki/php-1.45.0-wmf.23/includes/OutputTransform/Stages/HandleTOCMarkersDOM.php(183)	MediaWiki\OutputTransform\ContentDOMTransformStage->createElement(Wikimedia\Parsoid\DOM\Document, string, array, Wikimedia\Parsoid\DOM\DocumentFragment)
#3	/srv/mediawiki/php-1.45.0-wmf.23/includes/OutputTransform/Stages/HandleTOCMarkersDOM.php(111)	MediaWiki\OutputTransform\Stages\HandleTOCMarkersDOM->generateTocContent(Wikimedia\Parsoid\Core\TOCData, int, Wikimedia\Parsoid\DOM\Document)
#4	/srv/mediawiki/php-1.45.0-wmf.23/includes/OutputTransform/Stages/HandleTOCMarkersDOM.php(62)	MediaWiki\OutputTransform\Stages\HandleTOCMarkersDOM->generateToc(Wikimedia\Parsoid\Core\TOCData, LanguageMy, Wikimedia\Parsoid\DOM\Document, int)
#5	/srv/mediawiki/php-1.45.0-wmf.23/includes/OutputTransform/Stages/HandleTOCMarkersDOM.php(38)	MediaWiki\OutputTransform\Stages\HandleTOCMarkersDOM->injectToc(MediaWiki\Parser\ParserOutput, array, Wikimedia\Parsoid\DOM\Element)
#6	/srv/mediawiki/php-1.45.0-wmf.23/includes/OutputTransform/ContentDOMTransformStage.php(34)	MediaWiki\OutputTransform\Stages\HandleTOCMarkersDOM->transformDOM(Wikimedia\Parsoid\DOM\DocumentFragment, MediaWiki\Parser\ParserOutput, MediaWiki\Parser\ParserOptions, array)
#7	/srv/mediawiki/php-1.45.0-wmf.23/includes/OutputTransform/ContentHolderTransformStage.php(55)	MediaWiki\OutputTransform\ContentDOMTransformStage->transform(MediaWiki\Parser\ParserOutput, MediaWiki\Parser\ParserOptions, array)
#8	/srv/mediawiki/php-1.45.0-wmf.23/includes/OutputTransform/OutputTransformPipeline.php(79)	MediaWiki\OutputTransform\ContentHolderTransformStage->transform(MediaWiki\Parser\ParserOutput, MediaWiki\Parser\ParserOptions, array)
#9	/srv/mediawiki/php-1.45.0-wmf.23/includes/Output/OutputPage.php(2569)	MediaWiki\OutputTransform\OutputTransformPipeline->run(MediaWiki\Parser\ParserOutput, MediaWiki\Parser\ParserOptions, array)
#10	/srv/mediawiki/php-1.45.0-wmf.23/includes/Output/OutputPage.php(2651)	MediaWiki\Output\OutputPage->getParserOutputText(MediaWiki\Parser\ParserOutput, MediaWiki\Parser\ParserOptions, array)
#11	/srv/mediawiki/php-1.45.0-wmf.23/includes/page/Article.php(968)	MediaWiki\Output\OutputPage->addParserOutput(MediaWiki\Parser\ParserOutput, MediaWiki\Parser\ParserOptions, array)
#12	/srv/mediawiki/php-1.45.0-wmf.23/includes/page/Article.php(861)	MediaWiki\Page\Article->doOutputFromRenderStatus(MediaWiki\Revision\RevisionStoreRecord, MediaWiki\Status\Status, MediaWiki\Output\OutputPage, MediaWiki\Parser\ParserOptions, array)
#13	/srv/mediawiki/php-1.45.0-wmf.23/includes/page/Article.php(537)	MediaWiki\Page\Article->generateContentOutput(MediaWiki\User\User, MediaWiki\Parser\ParserOptions, int, MediaWiki\Output\OutputPage, array)
#14	/srv/mediawiki/php-1.45.0-wmf.23/includes/actions/ViewAction.php(71)	MediaWiki\Page\Article->view()
#15	/srv/mediawiki/php-1.45.0-wmf.23/includes/actions/ActionEntryPoint.php(734)	MediaWiki\Actions\ViewAction->show()
#16	/srv/mediawiki/php-1.45.0-wmf.23/includes/actions/ActionEntryPoint.php(505)	MediaWiki\Actions\ActionEntryPoint->performAction(MediaWiki\Page\Article, MediaWiki\Title\Title)
#17	/srv/mediawiki/php-1.45.0-wmf.23/includes/actions/ActionEntryPoint.php(143)	MediaWiki\Actions\ActionEntryPoint->performRequest()
#18	/srv/mediawiki/php-1.45.0-wmf.23/includes/MediaWikiEntryPoint.php(184)	MediaWiki\Actions\ActionEntryPoint->execute()
#19	/srv/mediawiki/php-1.45.0-wmf.23/index.php(44)	MediaWiki\MediaWikiEntryPoint->run()
#20	/srv/mediawiki/w/index.php(3)	require(string)
#21	{main}

Impact

Notes

Details

MediaWiki Version: 1.45.0-wmf.23
Request URL: https://mnw.wiktionary.org/wiki/%EC%9D%B4%EC%8A%AC%EB%9E%8C%EA%B5%90%EB%8F%84

Related Changes in Gerrit:

Subject	Repo	Branch	Lines +/-
Use DOMCompat to append document fragment	mediawiki/core	master	+3 -7
Do not insert empty document fragments as TOC lines	mediawiki/core	wmf/1.45.0-wmf.23	+2 -1
Do not insert empty document fragments as TOC lines	mediawiki/core	master	+2 -1

Customize query in gerrit

Related Objects

Mentioned In: T402548: PHP Warning: DOMNode::appendChild(): Document Fragment is empty
T405679: 1.45.0-wmf.23 deployment blockers
Mentioned Here: T402548: PHP Warning: DOMNode::appendChild(): Document Fragment is empty

Event Timeline

Zabe created this task.Oct 15 2025, 8:54 AM

Restricted Application added a subscriber: Aklapper. · View Herald TranscriptOct 15 2025, 8:54 AM

Zabe added a project: Content-Transform-Team.Oct 15 2025, 9:14 AM

There is another one with the same error message (T402548) but which is for Parsoid / Kartographer. This one looks different? It started as I have rolled 1.45.0-wmf.23 on group 1 wikis, examples of originating wikis:

mnwwiktionary	33
incubatorwiki	8
lmowiktionary	7
azwiktionary	2
omwiktionary	1

It started with 1.45.0-wmf.23 which I am deploying this week:

document_fragments.png (289×503 px, 17 KB)

Lot of them come from mnwwiktionary:

mnwwiktionary	1,483
test2wiki	222
lmowiktionary	207
elwiktionary	45
incubatorwiki	25
viwiktionary	18
fawiktionary	14
omwiktionary	13

Example page: https://mnw.wiktionary.org/wiki/sterns

hashar added a parent task: T405679: 1.45.0-wmf.23 deployment blockers.Oct 16 2025, 8:02 AM

hashar mentioned this in T405679: 1.45.0-wmf.23 deployment blockers.

I checked, this has no user-facing impact, train can go forward with (hopefully limited) logspam as the only consequence, for which I have a patch (let me commit that :) )

Perfect thank you for the quick triage! I am rolling the train and we can deal with the backport later on. Meanwhile I will simply filter out this specific log entry.

hashar removed a parent task: T405679: 1.45.0-wmf.23 deployment blockers.Oct 16 2025, 8:16 AM

Change #1196620 had a related patch set uploaded (by Isabelle Hurbain-Palatin; author: Isabelle Hurbain-Palatin):

[mediawiki/core@master] Do not insert empty document fragments as TOC lines

https://gerrit.wikimedia.org/r/1196620

gerritbot added a project: Patch-For-Review.Oct 16 2025, 8:17 AM

I have added the following filter to mute that specific error. When I checked earlier there was roughly one occurrence per minute which is hardly an issue.

{
  "query": {
    "bool": {
      "must_not": [
        {
          "bool": {
            "filter": [
              {
                "match_phrase": {
                  "error.message": "PHP Warning: DOMNode::appendChild(): Document Fragment is empty"
                }
              },
              {
                "match_phrase": {
                  "log.origin.file.name": "/srv/mediawiki/php-1.45.0-wmf.23/includes/OutputTransform/ContentDOMTransformStage.php"
                }
              },
              {
                "match_phrase": {
                  "log.origin.file.line": 70
                }
              }
            ]
          }
        }
      ]
    }
  }
}

Change #1196620 merged by jenkins-bot:

[mediawiki/core@master] Do not insert empty document fragments as TOC lines

https://gerrit.wikimedia.org/r/1196620

Maintenance_bot removed a project: Patch-For-Review.Oct 16 2025, 2:30 PM

I don't think it is worth the hassle to backport the patch, I have filtered the error log in the Opensearch dashboard and it is low volume so I don't think it causes any risk to the observability platform. I am marking this one resolved, and it will be deployed next week as part of the train. Thank you @ihurbain !

ReleaseTaggerBot added a project: MW-1.45-notes (1.45.0-wmf.24; 2025-10-21).Oct 16 2025, 3:00 PM

ABreault-WMF mentioned this in T402548: PHP Warning: DOMNode::appendChild(): Document Fragment is empty.Oct 21 2025, 7:50 PM

Change #1197708 had a related patch set uploaded (by Arlolra; author: Isabelle Hurbain-Palatin):

[mediawiki/core@wmf/1.45.0-wmf.23] Do not insert empty document fragments as TOC lines

https://gerrit.wikimedia.org/r/1197708

gerritbot added a project: Patch-For-Review.Oct 21 2025, 7:55 PM

Change #1197708 merged by jenkins-bot:

[mediawiki/core@wmf/1.45.0-wmf.23] Do not insert empty document fragments as TOC lines

https://gerrit.wikimedia.org/r/1197708

Maintenance_bot removed a project: Patch-For-Review.Oct 21 2025, 8:30 PM

Mentioned in SAL (#wikimedia-operations) [2025-10-21T20:31:04Z] <arlolra@deploy2002> Started scap sync-world: Backport for [[gerrit:1197708|Do not insert empty document fragments as TOC lines (T407323)]]

Mentioned in SAL (#wikimedia-operations) [2025-10-21T20:35:17Z] <arlolra@deploy2002> arlolra: Backport for [[gerrit:1197708|Do not insert empty document fragments as TOC lines (T407323)]] synced to the testservers (see https://wikitech.wikimedia.org/wiki/Mwdebug). Changes can now be verified there.

Mentioned in SAL (#wikimedia-operations) [2025-10-21T20:41:16Z] <arlolra@deploy2002> Finished scap sync-world: Backport for [[gerrit:1197708|Do not insert empty document fragments as TOC lines (T407323)]] (duration: 10m 12s)