Language mess in error messages

[wehro]

If the course language is English, but the user language is German, any error message is shown in two different languages.

[sangwinc]

I think this has already been fixed, and I can't reproduce it on the demo server (last release) or the current dev code.
https://stack-demo.maths.ed.ac.uk/demo/

Which version are you using?

[wehro]

Our Stack is 2025073100 on Moodle 5.0.

If this has been fixed since July, it’s fine. It’s not in my hands to update, sorry.

Your output shows a related problem, which I haven’t reported yet. A space is missing after the first sentence of the German error message.

[aharjula]

I doubt this is any known existing issue; I think this might be a local issue. This is my interpretation:

1. Both language strings seen in the screenshot are coming out of the same Moodle language system source (keys studentValidation_invalidAnswer and stackCas_missingRightBracket) and are called with the same session context language settings in the same STACK function, where the context does not get changed nor does control revert to Moodle between those language string extractions, so it cannot change the context either.
2. STACK itself does not change the language mid-processing, and Moodle cannot change it at that time, so there are a few options:
   • Either the strings come from some confused cache of language strings. Which would be very odd.
   • Or maybe someone has modified/overridden the local language packs, which is again a very odd thing to do.
   • Or maybe these strings do not come from the language packs, maybe someone has a partially translated special bespoke validator in their question. However, the screenshot implies validation at the syntax level, and that would be quite a feat, and as long as that is not a string input, it is impossible.
3. I think that it would be interesting to see what happens if someone purges some caches, in particular, the language strings cache, on that Moodle. If that helps, it may merit checking where those caches reside and if that place requires some attention.

I think that the issue Chris refers to was the AJAX/instant-validation language not matching the overridden language issue, but if that were the issue, then both strings would have the same language.

[wehro]

It does not look like a caching issue to me.
Here are screenshots for all possible combinations of languages:

Course language English, user language English

Course language English, user language German

Course language German, user language English

Course language German, user language German

[aharjula]

Well, to check if this is related to the AJAX/instant validation issue. Do confirm that the language does not change if you press the check or submit buttons.

If it changes, then someone needs to figure out what language is used for the $state contained errors before line 1466. Although, that makes little sense as the languages should then be GE-EN and not EN-GE in that special case.

[anst-i]

I can reproduce this using Moodle 5.1 and the current dev branch, but it's very strange.

I'm using course language English and user language German in the following screen recording: Loading the page and entering new input behaves differently!

Screencast.From.2025-12-19.13-31-29.mp4

This also happens for me with purged caches and previously unused input strings.

[aharjula]

So the fix for the AJAX/instant-validation issue is incomplete. The language setting does not propagate everywhere where it matters when using that validation. In this case, the input state has been populated with the global language strings before it is used to interpret the validation message in the overriding language.