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Banner on German Wikipedia and throwing NS_ERROR_FILE_CORRUPTED: error
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Stack trace and the sudden surge of errors suggests a central notice banner notice is causing this. Not sure which one.

Currently, this accounts for 986 errors in 12 hours and is our 3rd highest frequency error:

Event Timeline

Pcoombe added a subscriber: Pcoombe.

Timing coincides with campaign C20_WMDE_Test_09 going up, so yes it's probably one or both of B20_WMDE_Test_09_ctrl or B20_WMDE_Test_09_var. Pinging WMDE-Fundraising-Tech as owners of those banners.

WMF Fundraising saw a similar issue before in T264366#6510591 caused by corrupt Firefox profiles (, and all of these errors also appear to be in Firefox. We fixed it by wrapping the use of localStorage in a try/catch. Alternatively I believe the module can handle this.

Jdlrobson triaged this task as Unbreak Now! priority.Nov 5 2020, 5:08 PM

There were 2,429 errors in the last 24 hrs. For now I am calling UBN when a new error is introduced that exceeds 1,500 errors every 24hrs.
If it's a banner though it doesn't block the train.

This has been UBN for almost 2 weeks now. Is there some one we can directly ping @Pcoombe to ensure this gets attention?

Seems that @Pcoombe's comment regarding corrupt Firefox profiles points into the right direction.

I could not reproduce this using any specific browser functionality, but can confirm that this only happens in Firefox. This error has been reported to logstash since Sep 23rd and at a much lower rate during earlier banner tests, probably because of the traffic limit. There is a spike in early October which coincides with the Wikipedia Challenge banners.

Note: currently we are not capturing all errors for Chrome due to a bug in the instrumentation (T266517), so it is very likely the numbers are much higher and do include Chrome.

I've created a patch for our localstorage access, to guard against corruption in Firefox:

After redeploying all banners, the occurrences dropped to 0 (see Logstash).

Jdlrobson claimed this task.

Thank you for taking care of this!