Resolution: Won't Do
When having the pull strategy set as "Merging the pull request with the current target branch revision" for a mercurial repository the build is still ran against "The current pull request revision"
The following is put into the jenkins logs:-
`Building MERGE commits of PRs of Mercurial based repositories on BitBucket Cloud is not currently supported, falling back to HEAD commit`
In the code it has this comment next to the log `// TODO decorate with something that handles merge commits // FIXME file a Jenkins JIRA`
I couldn't see a JIRA ticket for this so I thought it best to create one so this can at least be tracked.