I would find such a tool to be extremely useful as well. I am working on an extension that uses a considerable amount of JavaScript and while we’re trying to find as many breakdowns as we can, it’s entirely possible we’ll miss something and the person who discovers the bug won’t be familiar with debugging tools like the in-browser JavaScript console. On January 18, 2017 at 8:26:32 AM, Amir E. Aharoni ( amir.aharoni(a)mail.huji.ac.il) wrote: Hallo Wikitech community, Remind me please, were there ever any efforts to get client-side JavaScript errors monitored centrally? What happens currently is that JS code can frequently fail, taking down the rest of JS on the page with it. It happens both with JS code properly deployed from Gerrit and loaded by RL, but even more so with local gadgets, Common.js, and user scripts. The most frequent effects of this into which I ran are Visual Editor not working at all and WikiEditor's toolbar not appearing in the source editing window. There are many more. On projects with a lot of editors and administrators, like the English and the German Wikipedia, this will probably be quickly noticed and fixed—sometimes fixed locally, and sometimes fixed in Gerrit and deployed in SWAT. But in smaller projects it can fail for months without being noticed. And when I say "smaller", I don't mean the tiny projects with almost no editors—such a thing happened recently in the Japanese Wikipedia, a top-10 project, and I helped administrators there to fix the buggy code, which appeared in the second most-popular gadget. I did this dozens of times, and Krinkle probably does this even more than me. Often admins from different projects help each other, and it is great that we have this mutual help in the community, but aren't there better ways to catch such errors? I remember there were discussions about this, but I don't remember what was the outcome. -- Amir Elisha Aharoni · אָמִיר אֱלִישָׁע אַהֲרוֹנִי http://aharoni.wordpress.com ‪“We're living in pieces, I want to live in peace.” – T. Moore‬ _______________________________________________ Wikitech-l mailing list Wikitech-l(a)lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikitech-l

I wrote 2 years ago a phantom-js based script to catch all JS errors in all wikis: https://github.com/eranroz/wiki-js-error-log See also: https://phabricator.wikimedia.org/T71519 On Wed, Jan 18, 2017 at 6:37 PM, Jeremy Baron <jeremy(a)tuxmachine.com> wrote:

UploadWizard has such a mechanism, recording all JavaScript exceptions that happen on https://commons.wikimedia.org/wiki/Special:UploadWizard (using some of the machinery originally designed for Sentry, some custom glue code, and some EventLogging definitions). Using EventLogging mostly works, but it has some strict limitations on the size of data you can record there, so we can't save for example error backtraces. That's still much better than nothing at all, though. You'll also find that, unless a problem is affecting literally everyone on every page, it's really difficult to separate problems in code you can fix from problems in code you can't. Turns out that a large number of people use very broken browser extensions, or user scripts, or browser, or entire computers, that throw exceptions left and right whenever the user looks at it wrong. Since browsers' security features and ResourceLoader's mechanisms often hide the real source of the error, you have to investigate everything by hand. And that's my experience only looking at errors happening on one page, on one wiki. :) -- Bartosz Dziewoński

Oh, and also, a more general limitation: the error messages may be localised, depending on the browser. I hope you speak Korean. -- Bartosz Dziewoński