Given:

Jenkins: Branch scanning with "Discover Branches Strategy" set to "Exclude branches that are also filed as PRs"

Bitbucket: Automatic merging enabled

When:

Merging changes from feature/X into release/Y, where automatic merge from release/Y into master fails.

Then:

Bitbucket creates new PR-Z for merging release/Y into master. Jenkins deletes old release/Y job, and creates new PR-Z job. Upon PR closure, PR job is deleted and release/Y job re-created starting from BUILD_NUMBER=1

The underlying issue is the ability to unintentionally delete branch jobs by simply opening a PR. As another example, it is also possible to delete master job by simply requesting master branch to be merged anywhere else.

I don't see any nice way around this, other than introducing another type of filter that would specify "permanent/sticky" jobs - ones that will never be deleted, only disabled if no longer matched by the normal branch filter. Any thoughts?