For clarity:
(1) Without any global options set and with 'cleanup' build step:
(2) With Global option 'Delete Perforce client' and with 'cleanup' build step:
P4 Task: remove client: jenkins-master-JENKINS-47107_-_Cleanup-8
... p4 client -d jenkins-master-JENKINS-47107_-_Cleanup-8 -p4 client -d jenkins-master-JENKINS-47107_-_Cleanup-8
Client jenkins-master-JENKINS-47107_-_Cleanup-8 deleted.
(3) With Global option 'Delete Workspace files' and with 'cleanup' build step:
P4 Task: cleanup client: jenkins-master-JENKINS-47107_-_Cleanup-0
P4 Task: unsyncing client: jenkins-master-JENKINS-47107_-_Cleanup-0
P4 Task: syncing files at change: 0
... p4 sync -f -q /var/lib/jenkins/workspace/JENKINS-47107 - Cleanup/...@0 -p4 sync -f -q /var/lib/jenkins/workspace/JENKINS-47107 - Cleanup/...@0
(4) With Global options 'Delete Perforce client' and 'Delete Workspace files'
P4 Task: cleanup client: jenkins-master-JENKINS-47107_-_Cleanup-9
P4 Task: unsyncing client: jenkins-master-JENKINS-47107_-_Cleanup-9
P4 Task: syncing files at change: 0
... p4 sync -f -q /var/lib/jenkins/workspace/JENKINS-47107 - Cleanup/...@0 -p4 sync -f -q /var/lib/jenkins/workspace/JENKINS-47107 - Cleanup/...@0
... totalFileSize 0
... totalFileCount 1
duration: (2ms)
... p4 client -o jenkins-master-JENKINS-47107_-_Cleanup-9 +... p4 revert /var/lib/jenkins/workspace/JENKINS-47107 - Cleanup/... -p4 revert /var/lib/jenkins/workspace/JENKINS-47107 - Cleanup/...
/var/lib/jenkins/workspace/JENKINS-47107 - Cleanup/... - file(s) not opened on this client.
P4 Task: remove client: jenkins-master-JENKINS-47107_-_Cleanup-9
... p4 client -d jenkins-master-JENKINS-47107_-_Cleanup-9 -p4 client -d jenkins-master-JENKINS-47107_-_Cleanup-9
Client jenkins-master-JENKINS-47107_-_Cleanup-9 deleted.
IMPORTANT NOTE: Groovy step "cleanup" without a paramater is not valid. Therefore if it is not used the 'cleanup' function must be fixed to not take true/false.
Suggest this is fixed or 'true/false' is removed from 'cleanup' and documentation states this is a global setting (bubble text and docs). Upping to B to raise awareness.