https://meta.wikimedia.org/wiki/User:Yerpo?action=edit

rohan.j.verma wrote:

Hello Sam,
I was investigating your bug and managed to recreate it when emitting your user page. I also tried to narrow down what part of your page was causing the error. However before I completed this it seems I can no longer reproduce the crash. Is this the same for you?

I suspect that the order of events was something like this:

• Page calls Module:Navbox, where list1 contains a transclusion of Special:LanguageStats/sl
• Scribunto expands the list1 arg, from the loop at lines 347–350.
• Something related to the transclusion of Special:LanguageStats/sl manages to somehow corrupt the Scribunto state. Not sure how. But the result is that the engine's interface is some non-object (probably null).
• Then when Scribunto tries to expand the next arg (group2 on the next iteration of the loop), it runs into that null interface, and boom.
• And then at some point, whatever it was about the data behind Special:LanguageStats/sl that was making it screw up the Scribunto state changed so it doesn't do it anymore.

Which makes this extremely difficult to reproduce and debug. Ugh.

Quite a few of these currently happening on wmf14

I've confirmed that it's Special:LanguageStats/sl: I created a module on meta that just returns the values of two parameters, and if I passed {{Special:LanguageStats/sl}} for the first one then this error occurred. Again, the error stopped occurring after a short time.

I also noted that page title on page preview of a page containing only {{Special:LanguageStats/sl}} (no Scribunto invocation at all) was being reported as "MediaWiki:Centralnotice-template-B13 0822 form newspacing left dr enYY" instead of "User:Anomie/Sandbox2" while the bug was occurring.

Other than the corrupt title, I also note the following differences between the output when the bug was occurring and when it wasn't:

• Group rows (the ones with [expand]/[collapse]) have "..." in the value columns instead of actual numbers. A number of the value rows do too, although the row for "MediaWiki:Centralnotice-template-B13 0822 form newspacing left dr enYY" is not among these.
• A bolded row for "Fundraising 2012" was present, with state "In Progress". There is another "In Progress" (but non-bolded) row in the non-bugged output, however.
• A bolded row for "WMF Blog Posts" was present, with empty state.
• The total row at the end also has "...".

(In reply to comment #4 by Reedy)

Quite a few of these currently happening on wmf14

Can this still be seen in logs recently?

(In reply to comment #4 by Reedy)

Quite a few of these currently happening on wmf14

Reedy: Can this still be seen in logs recently?

(In reply to comment #4 by Reedy)

Quite a few of these currently happening on wmf14

Reedy: Can this still be seen in logs recently?

Has anybody seen this in logs recently? Is this still an issue?