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Uncaught TypeError: Cannot read property 'tagName' of null
Closed, InvalidPublicPRODUCTION ERROR

Description

Error

MediaWiki version: n/a

message
Uncaught TypeError: Cannot read property 'tagName' of null

Impact

Notes

Details

Request ID
undefined
Request URL
https://www.mediawiki.org/wiki/Talk:Reading/Web/Desktop_Improvements#J'accuse!
Stack Trace
exception.trace
at Object.addListItem  https://www.mediawiki.org/w/load.php?lang=cs&modules=ext.discussionTools.init%7Cjquery%2Cmoment%2Coojs-ui-core&skin=vector&version=vmorw:23:454
at CommentController.js.CommentController.setup  https://www.mediawiki.org/w/load.php?lang=cs&modules=ext.discussionTools.init%7Cjquery%2Cmoment%2Coojs-ui-core&skin=vector&version=vmorw:10:885
at CommentController.js.CommentController.onReplyLinkClick  https://www.mediawiki.org/w/load.php?lang=cs&modules=ext.discussionTools.init%7Cjquery%2Cmoment%2Coojs-ui-core&skin=vector&version=vmorw:9:716
at HTMLAnchorElement.dispatch  https://www.mediawiki.org/w/load.php?lang=cs&modules=ext.discussionTools.init%7Cjquery%2Cmoment%2Coojs-ui-core&skin=vector&version=vmorw:299:742
at HTMLAnchorElement.elemData.handle  https://www.mediawiki.org/w/load.php?lang=cs&modules=ext.discussionTools.init%7Cjquery%2Cmoment%2Coojs-ui-core&skin=vector&version=vmorw:296:388

Event Timeline

Tacsipacsi subscribed.

Please note that Production error task subtype is for server-side errors, not for client-side ones like this one. Steps to reproduce are welcome—server-side errors are usually reproducible by just opening the same URL, but this is obviously not the case here.

Please note that Production error task subtype is for server-side errors, not for client-side ones like this one.

Tacsipacsi removed a project: Wikimedia-production-error.

I think that's not correct. JS errors are errors too and are in the scope of the tag that you removed (which is distinct from task subtype). Please read the tag description and maybe explain why client side errors are not in scope.

Yes, @Ammarpad is correct it shouldn't matter if the error is a client or server error Wikimedia-production-error - both show up in our logstash log tooling now and there is even a form there that creates a task with this tag. Just because they are not as easy to reproduce does not mean they are invalid - particularly if that results in an edit failing.

This is part of an initiative to get people thinking about client errors in the same way as server-side errors - and soon these will be blocking trains in the same way - however, we are still in the early stages of rollout.

Here's a screenshot of the tool in case you are interested and do not have access:

Screen Shot 2020-09-07 at 7.55.14 AM.png (810×2 px, 180 KB)

Also appears as

TypeError: null is not an object (evaluating 'parent.tagName')
t stack_trace 	
	at addListItem https://zh.wikipedia.org/w/load.php?lang=zh-cn&modules=ext.discussionTools.init%7Cjquery%2Coojs-ui-core%2Coojs-ui-widgets%7Cjquery.ui&skin=vector&version=q46dq:24:389
at https://zh.wikipedia.org/w/load.php?lang=zh-cn&modules=ext.discussionTools.init%7Cjquery%2Coojs-ui-core%2Coojs-ui-widgets%7Cjquery.ui&skin=vector&version=q46dq:12:88
at https://zh.wikipedia.org/w/load.php?lang=zh-cn&modules=ext.discussionTools.init%7Cjquery%2Coojs-ui-core%2Coojs-ui-widgets%7Cjquery.ui&skin=vector&version=q46dq:10:914
at dispatch https://zh.wikipedia.org/w/load.php?lang=zh-cn&modules=ext.discussionTools.init%7Cjquery%2Coojs-ui-core%2Coojs-ui-widgets%7Cjquery.ui&skin=vector&version=q46dq:310:747
matmarex added subscribers: ppelberg, Esanders.
matmarex subscribed.

I can't find any occurrences of this in Logstash today. Searching for "Cannot read property 'tagName' of null" gives some results, but they have different stack traces and are not occurring on talk pages. Searching for stack_trace:"Object.addListItem" or stack_trace:"*addListItem*" gives 0 results.

I'm guessing (based on the error messages) this might have been the same problem as T279445, although there's no way to tell for sure a year later.