Description Jörg Kubitz 2022-02-22 11:19:47 EST

..but tries to lock.acquire() in WorkManager.checkIn()

In for example bug 546828 the workaround was to not use a null rule. But it should be more consistent for all operations: 
for rule null we could either
a) do not lock workspace
b) interrupt autobuild

variant b) seems to be less intrusive, but the javadoc of
Workspace.prepareOperation() clearly states:
"*If* a scheduling rule is supplied, this method will block until it is safe to run."

so according to that description a null rule should not block. But who knows how that is used for ~ 20 years.

For example SaveManager.addParticipant() clearly expects mutal exclusion by using a null rule.

proposal: b) + fix javadoc