PHP Warning: Illegal string offset 'lang' from ApiVisualEditor.php
Closed, ResolvedPublicPRODUCTION ERROR
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Assigned To

Authored By

	Krinkle
	Mar 16 2019, 4:37 AM

Description

Error

Request ID: XIxtJApAEDIAAE3EcFsAAAAG

message

PHP Warning: Illegal string offset 'lang'

trace

#1 /srv/mediawiki/php-1.33.0-wmf.21/extensions/VisualEditor/includes/ApiVisualEditor.php(664): ApiVisualEditor->getLangLinks(Title)
#2 /srv/mediawiki/php-1.33.0-wmf.21/includes/api/ApiMain.php(1595): ApiVisualEditor->execute()
#3 /srv/mediawiki/php-1.33.0-wmf.21/includes/api/ApiMain.php(531): ApiMain->executeAction()
#4 /srv/mediawiki/php-1.33.0-wmf.21/includes/api/ApiMain.php(502): ApiMain->executeActionWithErrorHandling()
#5 /srv/mediawiki/php-1.33.0-wmf.21/api.php(87): ApiMain->execute()
#6 /srv/mediawiki/w/api.php(3): require(string)

Impact

Unknown.

Due to the error being non-fatal, the program unfortunately continues with unspecified behaviour. I do not know what the accidental outcome is and whether it happens to be correct, or whether it corrupts something on pages.

Notes

Seen about 700 times in the past week under Logstash/mediawiki-errors from PHP 7 beta testers.

The error is likely many times more frequent than that for all other users. However, HHVM does not have detection for this error. Instead, it casts the string 'lang' to the number 0 and returns the first character of the string that the code is performing ['lang'] on. This is most certainly not the intended behaviour.

Details

Related Changes in Gerrit:

	Subject	Repo	Branch	Lines +/-
	ApiVisualEditor: Fix PHP warning caused by unexpected API metadata	mediawiki/extensions/VisualEditor	master	+2 -1

Customize query in gerrit

Related Objects

Mentioned Here: T193718: Illegal string offset 'revid' in VisualEditor/includes/ApiVisualEditor.php

Event Timeline

Krinkle created this task.Mar 16 2019, 4:37 AM

Restricted Application added a subscriber: Aklapper. · View Herald TranscriptMar 16 2019, 4:37 AM

Krinkle updated the task description. (Show Details)Mar 16 2019, 4:40 AM

Hold on, I remember this bug:

In T193718#4232398, @matmarex wrote:

I think we're seeing the internal properties the API uses to nicely format JSON or XML output. You can see them in the web API with format=rawfm: https://en.wikipedia.beta.wmflabs.org/w/api.php?action=query&prop=revisions&format=json&rvprop=timestamp|user|parsedcomment|ids&rvlimit=25&pageids=7776&format=rawfm – note the "_element": "rev" (I think this is what we get in the foreach() loop) and other properties prefixed with _.

Looks like we can ask the API to strip these for us by calling ->getResultData( null, [ 'Strip' => 'all' ] ) instead of just ->getResultData().

Apparently, the 'Illegal string offset' warning is not emitted by HHVM, so we're not running into this at WMF: https://3v4l.org/YU0dV

On second thought, we use the result in our own output, so maybe stripping the metadata is not ideal. I'm actually not sure whether it's important in this particular case. So let's just add an is_array() check like in the other task.

Change 497362 had a related patch set uploaded (by Bartosz Dziewoński; owner: Bartosz Dziewoński):
[mediawiki/extensions/VisualEditor@master] ApiVisualEditor: Fix PHP warning caused by unexpected API metadata

https://gerrit.wikimedia.org/r/497362

gerritbot added a project: Patch-For-Review.Mar 18 2019, 10:01 PM

Change 497362 merged by jenkins-bot:
[mediawiki/extensions/VisualEditor@master] ApiVisualEditor: Fix PHP warning caused by unexpected API metadata

https://gerrit.wikimedia.org/r/497362

Jdforrester-WMF moved this task from Incoming to Engineering QA on the VisualEditor (Current work) board.Mar 18 2019, 10:35 PM

Jdforrester-WMF edited projects, added VisualEditor-MediaWiki, MW-1.33-notes (1.33.0-wmf.22; 2019-03-19); removed Patch-For-Review.

Last new occurrence in prod was 2019-03-21T12:26:24. Declaring this Resolved. Thank you!

Krinkle moved this task from Sep2019/1.34.wmf.21+ to Resolved on the Wikimedia-production-error board.May 6 2019, 6:18 PM

• mmodell changed the subtype of this task from "Task" to "Production Error".Aug 28 2019, 11:07 PM

PHP Warning: Illegal string offset 'lang' from ApiVisualEditor.phpClosed, ResolvedPublicPRODUCTION ERRORActions