Is there a good workaround for this? I don't think a simply "if" will get around it if you still want the code to execute.

Here's my scenario: I am synthesizing HDL in different phases. Some tools require a license for every phase, while some only when creating the final artifact. I want to share the licenses as much as possible and only have the phases lock the license when it's needed. My planned workaround is to have a "license pool" called "infinite" or something like that, and then have like 100 fake items in the pool to be checked out. Then switch out the resource name. But a quantity 0 would be easier and more obvious what I'm aiming for.

My workaround for the time being has been to reserve a resource with a blank name, something like:

resource_name = ''
if (...) { resource_name = 'whatever' }
lock(resource: resource_name) { ...

This works for my use case. I wanted the ability to lock for only some projects while still allowing all projects to call into the same central library.

Thanks; I didn't know an unnamed lock implicitly worked.

Does this fix in release 2.6 from today help?

This allows an "empty" lock when using the "extra" list:

def locks = []
if (cond) {
    locks << [quantity: 1, resource: 'foo']
}
lock(extra: locks) {
    // some block
}

I threw together a quick test and it looks like that works. It logs out this when it doesn't have anything to lock:

09:03:55  Trying to acquire lock on [nothing]
09:03:55  Lock acquired on [nothing] 

Which is better than what it said previously, something like "no resource specified - probably a bug." There were a few times people were misled by that message. I think that's good enough to close this out.