Currently, when using `wbeditentity` the pagename of the new/modified sitelink is normalized depending on the badges in [SiteLinksChangeOpDeserializer.php#118](https://github.com/wikimedia/Wikibase/blob/master/repo/includes/ChangeOp/Deserialization/SiteLinksChangeOpDeserializer.php#L118):
```lang=php,name=SiteLinksChangeOpDeserializer.php
if ( isset( $serialization['title'] ) ) {
$linkPage = $this->siteLinkPageNormalizer->normalize(
$linkSite,
$this->stringNormalizer->trimWhitespace( $serialization['title'] ),
$serialization['badges'] ?? []
);
```
However, that only happens if the `title` parameter is in fact set in the API payload. But the API specification allows for omitting this parameter when only editing the badges of a sitelink. This is a problem, because this ChangeOpDeserializer does not have access to the item and its existing sitelinks (yet).
**So we have to figure out how to normalize the pagename based on the new badges when it was omitted from the request.**
I see a few ways one could do that, all not great:
* change `wbeditentity` API spec to require the page name when editing badges
* This would be a Breaking Change which takes time until we're allowed to enforce it
* Modify the change request data that is passed into the deserializer
* This would mean modifying an extremely specific piece of data inside of EditEntity, which is much more general than that.
* This is probably the most hacky solution
* give the deserializer access to the item
* This would require changing at least the interface `ChangeOpDeserializer::createEntityChangeOp` which is used in a lot of very unrelated places
* Also, the ChangeOpDeserializer look like they are conceptually not supposed to know which Entity they're about specifically
* basically undo [818184: Allow sitelinks to redirects if redirect badge is present](https://gerrit.wikimedia.org/r/c/mediawiki/extensions/Wikibase/+/818184) and rather normalize the pagename when the ChangeOp is //applied// and not when it is //created//
* That would mean changing it in [ChangeOpSiteLink::apply](https://github.com/wikimedia/Wikibase/blob/master/repo/includes/ChangeOp/ChangeOpSiteLink.php#L108)
* We would have to somehow inject the SiteLinkPageNormalizer and maybe some Site store (probably another service)
* In that ChangeOp the pagename is expected to be already normalized and resolved. If we change that expectation, we have to be very careful where we do that and how that affects what is used in the summary comment
* The exception might now be thrown in a different place than before and thus require different logic FIXME: double check