Add consumeProcessOutputStream() and consumeProcessErrorStream()

These are easy enough to add I guess but you can just call them with null to achieve the same thing. So normally you would do:

def stdout = new StringBuilder() // or other options
def proc = ...
proc.waitForProcessOutput(stdout, null)

Using the waitFor variant does more resource cleanup for you.

I haven't tested that to see if it works but the API doesn't indicate that they can be null. I would have assumed that either it would crash or the stream wouldn't be read properly. Updating the documentation could be another option but as I pointed out the interface is inconsistent here.

I agree that we can make this more consistent. We should probably add the methods as you suggest:

consumeProcessOutputStream()
consumeProcessErrorStream()
waitForProcessOutputStream()
waitForProcessErrorStream()

but I am wondering whether we should take Groovy 2.0 as an opportunity to rename some of the existing methods:
consumeStreams instead of consumeProcessOutput and similarly waitForStreams or waitConsumingStreams instead of waitForProcessOutput. In which case I would remove "Process" from the name of the methods you are suggesting too. We would leave the old names around as aliases for a version or two.

I agree. I thought about opening a ticket for that but wasn't familiar with the history. I always have to re-read waitForProcessOutput() to confirm that it isn't doing what it implies - waiting until there's output and then stopping.