Module talk:Caller title

Edit request: use less expensive functions

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Tacsipacsi

I've made (what I think are) improvements to the code in Module:Caller title/sandbox—specifically, making the code use native Lua functions instead of preprocessing wikitext—and would appreciate either these changes being implemented or feedback on why they shouldn't be. Pinging @Tacsipacsi and @CptViraj since you've edited this module. —CalendulaAsteraceae (talk • contribs) 11:40, 25 December 2023 (UTC)

@CalendulaAsteraceae: First of all, the part that uses wikitext processing should run only on pages directly transcluding the module and not on pages that transclude templates transcluding this module, so I wouldn’t care much about its performance. (I’m not against optimizing its performance, though, as long as the code doesn’t become less readable.)

However, your code is wrong at several places:

• mw.language.getContentLanguage() returns the content language, not the page language. The content language is always English on Commons, the page language is usually English (except on translation pages, but those use the other code path), however not always. For example, try transcluding {{#invoke:Caller title|lang|base={{subst:FULLPAGENAME}}}} and the sandbox version on Kezdőlap – the live version correctly returns hu, your version incorrectly returns en. A correct solution would be using the function to be introduced phab:T161976.
• mw.title.getCurrentTitle() returns the title of the page it displays on, not the title of the template that directly transcludes it. The whole point of using the module is to be able to query the language of the translated template itself rather than the language of the page the template is transcluded in. If we wanted the latter, we could just use {{SUBPAGENAME}}, without any Lua involved.
• Calling mw.text.trim() is not wrong, but unnecessary, going against your goal of optimization. Values of named parameters are always trimmed before being passed to modules (or templates).
• The base ~= '' check is also unnecessary: since the title of the current page will never be empty, the other condition will catch cases when |base= is not provided.
• (Adding require('strict') also decreases performance, but it serves a purpose, so it may still be worth it.)
• The extra checks on frame are unnecessary and can lead to silent breakage. It’s impossible not to provide a frame from wikitext, and this module is not designed to be called from other modules – if one does so without providing a frame, it’s their problem; garbage in, garbage out.

—Tacsipacsi (talk) 20:34, 25 December 2023 (UTC)

@Tacsipacsi: Thank you for your feedback! Now that the pageLang function has been introduced, I have an updated proposal in Module:Caller title/sandbox. —CalendulaAsteraceae (talk • contribs) 22:47, 20 February 2024 (UTC)

@CalendulaAsteraceae: I am pleased to see the arrival of pageLang too (it was a long time coming because MW hooks were screwed up and that affected several MW extensions) but the problem with it is it stupidly always increases the "expensive" count, even when other "expensive" data about the same page has already been fetched. I find it amusing you propose that under this thread heading of "Edit request: use less expensive functions". That said, it does finally solve the issue of obtaining the language of any page in the system without depending on the subpage naming scheme used by some translation architectures. This means base is actually entirely unneeded now and there is no reason to depend on the subpage name at all (which has been pointed out might not be the page language code or any page language code at all). —Uzume (talk) 06:40, 27 April 2024 (UTC)

@Tacsipacsi: The current deployment could be optimized by changing line 11 to: local parts = mw.text.split(title, '/', true) since that was already done on line 9 above. Of course I have noticed how things that once depended on this have since mostly moved to {{TRANSLATIONLANGUAGE}} after your gerrit:992484. Someone probably ought to look into Special:WhatLinksHere/Template:TRANSLATIONLANGUAGE which looks like may have been caused by subst:. —Uzume (talk) 06:40, 27 April 2024 (UTC)

I find it amusing you propose that under this thread heading of "Edit request: use less expensive functions". […] This means base is actually entirely unneeded now […].

Actually, it’s probably still cheaper in terms of computing power, even if it increments the expensive parser function count. And it runs (or at least it’s designed to run) only on direct transclusion, not on pages transcluding the transcluding template, so it’s unlikely to hit the limits because of this. Except if you remove the |base= parameter: then, it would run on all 21M pages currently using this module, likely several times per page. (And would rightfully increment the expensive parser function count: every time a page’s language is queried, it means a DB query plus a few hook calls, of which at least Translate also does some DB queries.)

The current deployment could be optimized by changing line 11 to: local parts = mw.text.split(title, '/', true) since that was already done on line 9 above. Of course I have noticed how things that once depended on this have since mostly moved to {{TRANSLATIONLANGUAGE}} after your gerrit:992484.

Indeed, it could be optimized, but every optimization needs reparsing all 21M pages using the module, which is quite expensive, so many pages need to be edited and reparsed subsequently for it to be a net win. Instead of optimizing the module, its usages should be replaced. Maybe a few will remain for whatever reason: at that point, the module could be optimized to allow those to run more quickly, as the optimization won’t cause many reparses anymore (but it won’t actually matter much exactly because the low number of affected pages).

Someone probably ought to look into Special:WhatLinksHere/Template:TRANSLATIONLANGUAGE which looks like may have been caused by subst:.

I think it’s more likely to be copy-paste than subst:, and actually both pages long predate my patch (as my patch title notes, it makes {{TRANSLATIONLANGUAGE}} available outside of translate tags – they have already been usable within translate tags for some time, and these pages probably used them that way). Yes, they should be fixed, but I’m not sure if the fix is replacing the magic word with en or marking the pages for translation.

(CalendulaAsteraceae, sorry for not replying earlier. I was waiting with the answer for my patch to be merged, but forgot to do so by the time it was merged.) —Tacsipacsi (talk) 08:48, 27 April 2024 (UTC)