Change 219244 had a related patch set uploaded (by John Vandenberg):
Add support for adding/removing statements in PropertyPage

https://gerrit.wikimedia.org/r/219244

So, property claims can have references/sources.

That means that the only ItemPage-specific data is sitelinks. They dont appears to be valid for properties. But perhaps we should check if the Wikibase team intend to add sitelinks/badges to Properties?

In T92669#1403308, @jayvdb wrote:

So, property claims can have references/sources.

That means that the only ItemPage-specific data is sitelinks. They dont appears to be valid for properties. But perhaps we should check if the Wikibase team intend to add sitelinks/badges to Properties?

Maybe we should split attributes and methods into WikibasePageWithLabels, WikibasePageWithSitelinks, WikibasePageWithClaims, etc., then make ItemPage and PropertyPage subclass them accordingly.

In T92669#1404090, @Ricordisamoa wrote:

In T92669#1403308, @jayvdb wrote:

So, property claims can have references/sources.

That means that the only ItemPage-specific data is sitelinks. They dont appears to be valid for properties. But perhaps we should check if the Wikibase team intend to add sitelinks/badges to Properties?

Maybe we should split attributes and methods into WikibasePageWithLabels, WikibasePageWithSitelinks, WikibasePageWithClaims, etc., then make ItemPage and PropertyPage subclass them accordingly.

WikibasePageWithLabels doesnt seem to be different from WikibasePage. In the data model, it appears that all entities implement labels, aliases and descriptions.
https://github.com/wmde/WikibaseDataModel/blob/master/src/Entity/Entity.php
However I can see some value in separating the implementation of 'labels, aliases and descriptions' from the entity.

..WithClaims maps to the data models StatementListHolder, and ..WithSitelinks maps to the data model SiteLinkList, so there is a sound basis to create separate classes for each of those.

A much cheaper approach is for WikibasePage to provide (perhaps limited) support for whatever keys appear in the JSON, and subclasses provide any special properties that are needed. WikibasePage.editEntity probably already does support writing for 'Property' entities; we just need to add more flexibility to other parts of WikibasePage. That will buy us some time so a better model can be created in T102741, where Page concepts are not mixed up in the data model.

Change 219244 had a related patch set uploaded (by Ladsgroup):
Add support for statements in PropertyPage

https://gerrit.wikimedia.org/r/219244

Change 219244 merged by jenkins-bot:
Add support for statements in PropertyPage

https://gerrit.wikimedia.org/r/219244

In T92669#1453180, @jayvdb wrote:

In T92669#1453171, @Ricordisamoa wrote:

addClaim and removeClaims methods are still missing from PropertyPage.

The problem has been resolved. If you wish to add extra ways to modify the items, propose a patch.

Err, half-resolved. Of course PropertyPage should now support all of ItemPage's methods dealing with claims.

We talked about this in gerrit and we agreed on not moving addClaim and removeClaims. Even though I'm not a big fan of this approach (T107712) but since we have T113131 already. I think it's safe to close this task.

addClaim and removeClaims are *NOT* deprecated.