A goroutine leak in manager/state/raft/transport/transport_test.go

[user12031]

When call New() at https://github.com/moby/swarmkit/blob/e8ecf83ee08e14a05e28992dc304576079d403c7/manager/state/raft/transport/mock_raft_test.go#L68 A goroutine is created to execute run() in New() https://github.com/moby/swarmkit/blob/e8ecf83ee08e14a05e28992dc304576079d403c7/manager/state/raft/transport/transport.go#L79 And the run() can return when case <-ctx.Done() get executed https://github.com/moby/swarmkit/blob/e8ecf83ee08e14a05e28992dc304576079d403c7/manager/state/raft/transport/transport.go#L100-L105

However, there is no tr.Stop() to cancel the context after calling New() sometimes. So the goroutine will block forever and leak. https://github.com/moby/swarmkit/blob/e8ecf83ee08e14a05e28992dc304576079d403c7/manager/state/raft/transport/transport.go#L119-L122

How to reproduce: You can use goleak testing the function to reproduce the bug. For the test function , The newMockRaft( ) is called four times, but only one c.Get(3).Stop() get exectued. So goroutines leak. https://github.com/moby/swarmkit/blob/e8ecf83ee08e14a05e28992dc304576079d403c7/manager/state/raft/transport/transport_test.go#L214 https://github.com/moby/swarmkit/blob/e8ecf83ee08e14a05e28992dc304576079d403c7/manager/state/raft/transport/transport_test.go#L230

The partial output is as follows:

leaks.go:78: found unexpected goroutines:
        [Goroutine 9 in state select, with github.com/moby/swarmkit/v2/manager/state/raft/transport.(*Transport).run on top of the stack:
        goroutine 9 [select]:
        github.com/moby/swarmkit/v2/manager/state/raft/transport.(*Transport).run(0xc0000365f0, {0xe26d20, 0xc0000365a0})
        	/home/song2048/桌面/goProject/src/GoPV/GoPV/testdata/real-GoProjects/src/github.com/swarmkit/manager/state/raft/transport/transport.go:111 +0x1e7
        created by github.com/moby/swarmkit/v2/manager/state/raft/transport.New in goroutine 8
        	/home/song2048/桌面/goProject/src/GoPV/GoPV/testdata/real-GoProjects/src/github.com/swarmkit/manager/state/raft/transport/transport.go:80 +0x29c

How to fix the bug: For the test function, we should call stop() three times at the end of the function to avoid leaking goroutines.

c.Get(1).Stop()
c.Get(2).Stop()
nr.Stop()