Wrong description language for Nearby upload

[nicolas-raoul]

Steps to reproduce:

1. Change the sandbox item's geolocation to somewhere near you (or use FakeGPS or scroll to its current location and press "Search in this area") and change its "instance of" to "embassy", remove its "image" if it has one.
2. Change your Android language to Hebrew (might work with other non-English languages)
3. Open the app, tap "Nearby"
4. Find the sandbox item
5. Tap the + and upload a picture for it.
6. The proposed description is in Upper Sorbian instead of Hebrew.

There are two problems with this:

• If "embassy" had no label for Hebrew and the app had to fallback to Upper Sorbian, then the description's language selection dropdown UI should have "hsb" selected instead of "iw"
• Actually "embassy" (https://www.wikidata.org/wiki/Q3917681) HAS a label for Hebrew. Not sure why it was not used. Upper Sorbian is the latest language a label has been added for, that might be why (https://www.wikidata.org/w/index.php?title=Q3917681&action=history). In any case it is a bug.

[nicolas-raoul]

Another example:
description should not be set to en, it should be set to ja because the description is in Japanese.

[nicolas-raoul]

I think the cause of the problem is that the SPARQL request coalesces languages, and we have no way to know what language was used:

 SAMPLE(COALESCE(?itemLabelPreferredLanguage, ?itemLabelAnyLanguage)) as ?label

As you can see, the label in language itemLabelPreferredLanguage is used if it exists, but if it does not exist, a label in any other language is used (randomly and we don't know which one).

Solution

When the user proceed with uploading a picture for that nearby item, we should run another request on that particular item only, that gets us all language-label pairs, and either take only the one we had displayed to the user, or even add all of them.