bingle-admin wrote:

Prioritization and scheduling of this bug is tracked on Trello card https://trello.com/c/7A2WdG6x

Sam Reed: are there any other notices originating from ApiMobileView.php at around the same time?

For this to happen ApiMobileView#getData, which returns the required data about a page, must return an empty array without the 'lastmodifiedby' key set. This can happen in one of two ways:

1. the cache entry corresponding to the page has become invalid
2. the page is a redirect to a page in a virtual namespace (NS_SPECIAL, NS_MEDIA)

Disregarding #1 because it feels a lot less likely than #2: there's nothing in ApiMobileView#execute protecting against #getData returning an empty array, so when it does, there'll be a whole bunch of undefined index notices triggered for the following indices:

• lastmodified
• lastmodifiedby
• revision
• id
• languagecount
• displaytitle
• pageprops

gerritadmin wrote:

Change 172258 had a related patch set uploaded by Phuedx:
Die with an error if the title redirects to media

https://gerrit.wikimedia.org/r/172258

Just had a look again now, and grepping for "ApiMobileView" literally only finds the stuff on line 98, and nothing more if I grep for "MobileFrontend"

It's probably worth noting this will happen on zend on production too, just we don't surface these things in the logs...

gerritadmin wrote:

Change 172258 merged by jenkins-bot:
Fix "Undefined index" notices in ApiMobileView

https://gerrit.wikimedia.org/r/172258

The patch is merged, and should be online on mw.org since Wednesday. Sam, can you check the logs and reopen if there are still errors? :)