I think we can declare this one resolved.

Change 595508 merged by jenkins-bot:
[mediawiki/extensions/Wikibase@master] Introduce ignoreDuplicateMainSnak param to wbsetclaim

Mentioned in SAL (#wikimedia-operations) [2020-05-11T19:03:24Z] <Zoranzoki21> T235414 is wrong task number, T235415 is correct

Mentioned in SAL (#wikimedia-operations) [2020-05-11T19:02:37Z] <catrope@deploy1001> Synchronized wmf-config/InitialiseSettings.php: Add *.bollywoodhungama.in and *.britishmuseum.org to $wgCopyUploadDomains (T235414, T251882) (duration: 00m 57s)

Change 595510 had a related patch set uploaded (by Cparle; owner: Cparle):
[mediawiki/extensions/MachineVision@master] Prevent duplicate statements

Change 595508 had a related patch set uploaded (by Cparle; owner: Cparle):
[mediawiki/extensions/Wikibase@master] Introduce ignoreDuplicateMainSnak param to wbsetclaim

In T234457#6085961, @Cparle wrote:

@Addshore 's proposed solution was a new param in wbsetclaim that says "don't create a duplicate mainsnak".

@Addshore 's proposed solution was a new param in wbsetclaim that says "don't create a duplicate mainsnak".

@Addshore we talked about a potential for this solution at last week's WMDE-WMF meeting. Any further thoughts from that discussion?

In general this makes sense to me but the semantics need to be very clear. I fear the following scenario might cause different people to expect different things to happen: if a statement with value a, qualifier b, and reference c already exists and then someone tries to store value a again, does this count as a new statement or not? Strictly speaking in the WB sense no it does not. But I can see arguments coming up why it should.

In T234457#5999020, @Ramsey-WMF wrote:

A better solution would be for wbsetclaim to provide an affordance to set a claim conditionally on it not already existing. But that would require support from the Wikibase devs, for code review at the very least.

@Addshore thoughts on how difficult this would be to implement on the Wikibase side? Thanks! 🙂

A better solution would be for wbsetclaim to provide an affordance to set a claim conditionally on it not already existing. But that would require support from the Wikibase devs, for code review at the very least.

Pinging @Cparle so he can have some context in prep for tomorrow's estimation meeting ☑

As things stand today, I think the frontend will have to request and examine the existing claims before conditionally sending the wbsetclaim requests.

Is there a potential workaround to prevent this specific problem when using 'wbsetclaim'?

Yes, this can once again happen as a result of updating depicts setting to use the wbsetclaim API to resolve T241242.

@Mholloway reopening this one because it seems there might have been a regression and CAT can again add statements that already exist. 😢

No failures of the CategoryMembershipChangeJob job in production over the last 30 days, except unrelated ones:

Done enough.

Change 579705 merged by jenkins-bot:
[mediawiki/extensions/Kartographer@master] Use mw.util.debounce