Increasing memory usage when only using spin_once

If the timeout in spin_once is set to zero (see snippet below) the program will continuously allocate new memory. If any other value or the default infinite timeout is chosen, everything works fine.

rclpy.init(args)
node = rclpy.create_node('test_node')
while rclpy.ok():
    rclpy.spin_once(node, 0)

[dirk-thomas]

With all the referenced PRs merged I can run the infinite spin_once loop as well as the large publisher (and a corresponding subscriber) with constant memory usage. 🎉

@ArkturusMengsk @IanTheEngineer @srsidd @BrannonKing please give the current state a try and report back how your experience is. I will close this ticket for now but if there are still reproducible examples left which need fixing it can be reopened. Thanks.

[clalancette]

No, I didn’t rebuild Python and all of that (which that document suggests). I fired up the test program from the first comment, and after about 30 seconds of running, I’m now up to 3g resident memory (confirmed using top). I killed it at that point; something is clearly leaking a lot of memory pretty quickly. If I run the same program, but leave timeout_sec as None (the default), no memory is leaked at all.