Jenkins parameterized job that only queues one build

Question

Imagine a Jenkins job A which takes 1 minute to run, and job B which takes 5 minutes.

If we configure job A to trigger job B, while job B is running job A may run 5

Answer 1

In case you're using Git, this is now supported by the "Combine Queued git hashes" under the Triggering/ Parameters/ Pass-through option. The first Git plugin version that should actually work with this is 1.1.27 (see Jenkins-15160)