Exception: JSON serialization of config data failed. (via OutputPage::getBottomScripts)
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Authored By

	brennen
	Jan 26 2023, 4:18 PM

Description

Error

mwversion: 1.40.0-wmf.19
reqId: 3b62e449-fddd-4dd1-a852-05265ed24ce6
Find reqId in Logstash

normalized_message

[{reqId}] {exception_url}   Exception: JSON serialization of config data failed. This usually means the config data is not valid UTF-8.

exception.trace

from /srv/mediawiki/php-1.40.0-wmf.19/includes/ResourceLoader/ResourceLoader.php(1600)
#0 /srv/mediawiki/php-1.40.0-wmf.19/includes/OutputPage.php(3500): MediaWiki\ResourceLoader\ResourceLoader::makeConfigSetScript(array)
#1 /srv/mediawiki/php-1.40.0-wmf.19/includes/OutputPage.php(4500): OutputPage->getBottomScripts(string)
#2 /srv/mediawiki/php-1.40.0-wmf.19/includes/skins/SkinMustache.php(66): OutputPage->tailElement(MediaWiki\Skins\Vector\SkinVectorLegacy)
#3 /srv/mediawiki/php-1.40.0-wmf.19/includes/skins/SkinTemplate.php(179): SkinMustache->generateHTML()
#4 /srv/mediawiki/php-1.40.0-wmf.19/includes/OutputPage.php(2887): SkinTemplate->outputPage()
#5 /srv/mediawiki/php-1.40.0-wmf.19/includes/MediaWiki.php(933): OutputPage->output(boolean)
#6 /srv/mediawiki/php-1.40.0-wmf.19/includes/MediaWiki.php(571): MediaWiki->main()
#7 /srv/mediawiki/php-1.40.0-wmf.19/index.php(50): MediaWiki->run()
#8 /srv/mediawiki/php-1.40.0-wmf.19/index.php(46): wfIndexMain()
#9 /srv/mediawiki/w/index.php(3): require(string)
#10 {main}

Impact

Notes

See a handful of these in 1.40.0-wmf.20 (T325583). Seems like T208689: Fatal error: JSON serialization of config data failed, invalid UTF-8 (via Scribunto) over again. I am guessing that this is a situation which should result in a user-facing error rather than an exception hitting the logs.

Details

Request URL: https://de.wikipedia.org/wiki/Spezial:Vorlagenspielwiese

Related Objects

Mentioned In: T329330: TypeError: Cannot read properties of null (reading 'toLowerCase') at at mw.language.getData
Mentioned Here: T206475: Users are unable to edit (add new topics to) [[:fa:wikipedia:پرسش‌های متفرقه]]
T207876: Fatal error from ResourceLoader: JSON serialization of config data failed (due to wgInternalRedirectTargetUrl)
T329330: TypeError: Cannot read properties of null (reading 'toLowerCase') at at mw.language.getData
T208689: Fatal error: JSON serialization of config data failed, invalid UTF-8 (via Scribunto)
T325583: 1.40.0-wmf.20 deployment blockers

Event Timeline

brennen created this task.Jan 26 2023, 4:18 PM

Restricted Application added a subscriber: Aklapper. · View Herald TranscriptJan 26 2023, 4:18 PM

brennen moved this task from Backlog to Logs/Train on the User-brennen board.Jan 26 2023, 4:18 PM

Agusbou2015 subscribed.Jan 26 2023, 4:55 PM

brennen moved this task from Untriaged to Jan 2023 on the Wikimedia-production-error board.Jan 26 2023, 4:57 PM

Krinkle renamed this task from Exception: JSON serialization of config data failed. This usually means the config data is not valid UTF-8. to Exception: JSON serialization of config data failed. (via OutputPage::getBottomScripts).Feb 14 2023, 11:01 PM

Krinkle mentioned this in T329330: TypeError: Cannot read properties of null (reading 'toLowerCase') at at mw.language.getData.Feb 14 2023, 11:21 PM

Quoting from the other task as the same applies here:

In T329330#8616782, @Krinkle wrote:

[These kinds of errors] ar is most likely due to an extension adding a key-value pair to mw.config with a string that is not valid UTF-8. This means it can't be encoded as JSON, and thus fails the blob. […]

This seems to come up once or twice a year, with usually a dedicated task for specific breakages once identified, such as:

core mw.config wgInternalRedirectTargetUrl: T207876: Fatal error from ResourceLoader: JSON serialization of config data failed (due to wgInternalRedirectTargetUrl)

Scribunto mw.config data: T208689: Fatal error: JSON serialization of config data failed, invalid UTF-8 (via Scribunto)

Flow mw.config data: T206475: Users are unable to edit (add new topics to) [[:fa:wikipedia:پرسش‌های متفرقه]]

The trace in the task description here contains OutputPage->getBottomScripts(string) which narrows it down to three keys:

wgPageParseReport
wgDiscussionToolsPageThreads (via LateJSConfigVarNames)
wgGraphSpecs (via LateJSConfigVarNames)

To know which one, though, would require a reproduction case that is more reliable than the given Special:TemplateSandbox URL, since that special page is empty when accessed directly. The person using it will have entered some arbitrary wikitext to preview. You'd need to know that wikitext, or find an instance of the error on a regular page.

brennen unsubscribed.Sep 11 2023, 7:23 PM

Exception: JSON serialization of config data failed. (via OutputPage::getBottomScripts)Open, Needs TriagePublicPRODUCTION ERRORActions