This only occurs on Persian Wikipedia right now. When you open a page (even logged out and with an empty cache), you get an error message in the JS console which reads:
[V@nHVQpAAEUAAAkm-KcAAAAW] 2016-09-27 01:11:49: Fatal exception of type "BadMethodCallException"
I thought this could be a local JS but I cannot find any common JS which would throw that exception.
| Subject | Repo | Branch | Lines +/- | |
|---|---|---|---|---|
| resourceloader: Fix undefined getPrefixedText() | mediawiki/core | master | +15 -3 |
I think this is causing the PROBLEM - MediaWiki exceptions and fatals per minute on graphite1001 is CRITICAL: CRITICAL: 40.00% of data above the critical threshold [50.0] every so often in #wikimedia-operations.
Change 313043 had a related patch set uploaded (by Krinkle):
resourceloader: Fix undefined getPrefixedText()
Change 313153 had a related patch set uploaded (by Krinkle):
resourceloader: Fix undefined getPrefixedText()
rMWfef64dc685fd has landed in master and a backport has been proposed to wmf.20. However, due to the no-deploy policy this week, I've not deployed that backport.
I did apply it to a canary server for a while (mw1017) and logged a subsequent request to fa.wikipedia.org and its load.php?modules=startup&only=scripts endpoint.
Produces the following warnings:
Invalid wiki page title "MediaWiki:Gadget-refStyle.css[ResourceLoader]" in ResourceLoaderWikiModule::preloadTitleInfo
Invalid wiki page title "MediaWiki:Gadget-refStyle.css[ResourceLoader]" in ResourceLoaderWikiModule::preloadTitleInfo
So this is merely a case where the input is genuinely broken. The "refStyle" gadget was equally broken on fa.wikipedia.org before the regression from dbe592df. However, the recent regression made the error easier to detect since ResourceLoader catches the exception in PHP, and (manually) copies the error message to be displayed in the "error" section of the browser developer console. (It was not a run-time exception in JavaScript and will not have affected the run-time of any other modules).
In the end, this is mostly a scary message that started to show up for tech-savvy users peeking in the browser error console on wikis where there is a gadget with a pre-existing syntax error in the definition of a gadget.
The proposed patch avoids this exception, restores silently failure mode, in favour of server-side logging.
The error logging may become a tad too verbose and isn't terribly useful since right now the Gadgets extension is not validating its input before registering the ResourceLoader module. The appropiate place to detect this syntax error and (silently) discard it would be in the Gadgets extension, ResourceLoader should not tolerate this.
Once that is fixed, we can restore the exception and/or raise log level from info to warning.
For production, I've resolved the exception by fixing the underlying syntax error in an edit on fa.wikipedia.org.
Thanks Krinkle. I think the biggest issuse I had here was not the fact that there was this error in the console, but the fact that it was a useless warning (who knows what "V@nHVQpAAEUAAAkm-KcAAAAW" stood for?!) so in addition to the benefits you mentioned above (silent alert, etc) I like your patch because it provides a more meaningful log message.
Change 313153 abandoned by Krinkle:
resourceloader: Fix undefined getPrefixedText()
Reason:
Will roll out next week in the train. No deploys this week.