SitesService#deriveSite had an issue, that it may fail returning the derived site, if the provided targetSiteId is null. As a result, it returned null in these cases and worse: The derived site was invalid as it had no site ID set.

With this change, we apply the same default as already used by the derive-site workflow, thus, to create a random site ID on demand.

We also changed the contract of SitesService#deriveSite, so that it does not return null anymore. While it is now always non-null, we skipped adding method contract @NonNull, as this may have triggered your static code analysis.

Subtle Breaking Changes

As stated, the behavior of deriveSite changed a little, creating a random site ID, if required. This does not affect any of the code that ships with CoreMedia Blueprint, but your code may rely on the old unset site ID behavior.

Also, the non-null contract (as stated, not declared explicitly) is now enforced in SiteService#deriveSite. If, for any reason, the site cannot be found after deriving it, it will now fail with a NullPointerException and a clear message, what site failed to be created.

(CMS-23139)