Hi all!

This is an announcement for a breaking change to the default value of a parameter of the WikibaseQualityConstraints constraint checking API, to go live on 26 February 2018. It potentially affects clients that use the *wbcheckconstraints* API action. (We are not aware of any such clients apart from the *checkConstraints* gadget, which is not affected.)

Recently, we added a status parameter to the *wbcheckconstraints* API action, with the intention that API users can declare ahead of time which results they’re actually interested in, so that other results don’t need to be sent to them: specifically, for most items the vast majority of results indicate compliance with a constraint, which we expect most users aren’t interested in.

*On 26 February 2018, we will change the default value of the status parameter to violation|warning|bad-parameters.* We assume that most users of the API will only be interested in results that actually indicate problems, and this should significantly reduce the size of API responses. Users who wish to receive all results, regardless of status, should specify status=* in their API requests.

Our motivation for this change is that we want to enable caching of constraint check results, but don’t want to bloat the cache with tons of compliance and not-in-scope results that we don’t even show in the gadget. With the status parameter, we can store only problematic results in the cache, while still guaranteeing that the response we send is complete, since the request indicated that it only needs these results anyways. This also means that when we enable caching (see phabricator:T184812 https://phabricator.wikimedia.org/T184812), only requests with status=violation|warning|bad-parameters will benefit from it.

Please let us know if you have any questions.

-- Lucas

Relevant tickets:

- phabricator:T183927 https://phabricator.wikimedia.org/T183927 - phabricator:T184812 https://phabricator.wikimedia.org/T184812 - phabricator:T184937 https://phabricator.wikimedia.org/T184937