panic (close of closed channel) in TestCallReceiverRpc
zenhack opened this issue · comments
Per #346; haven't dug into this at all yet, but I assume this has been there and is just rare enough to have not cropped up before. It passed ~250 times in that run before failing...
https://github.com/capnproto/go-capnproto2/actions/runs/3537277747/jobs/5937100516#step:7:488
--- FAIL: TestCallReceiverAnswerRpc (0.00s)
panic: close of closed channel [recovered]
panic: close of closed channel
goroutine 39 [running]:
testing.tRunner.func1.2({0x829bd80, 0x8334130})
/opt/hostedtoolcache/go/1.19.3/x64/src/testing/testing.go:1396 +0x2ab
testing.tRunner.func1()
/opt/hostedtoolcache/go/1.19.3/x64/src/testing/testing.go:1399 +0x41f
panic({0x829bd80, 0x8334130})
/opt/hostedtoolcache/go/1.19.3/x64/src/runtime/panic.go:884 +0x1c3
capnproto.org/go/capnp/v3.Client.Release({0x8c604b0})
/home/runner/work/go-capnproto2/go-capnproto2/capability.go:584 +0xe6
capnproto.org/go/capnp/v3.(*Message).Reset(0x8c64540, {0x0, 0x0})
/home/runner/work/go-capnproto2/go-capnproto2/message.go:134 +0xc6
capnproto.org/go/capnp/v3/rpc/transport.(*transport).RecvMessage.func1()
/home/runner/work/go-capnproto2/go-capnproto2/rpc/transport/transport.go:183 +0x30
capnproto.org/go/capnp/v3/rpc.(*question).PipelineSend.func3()
/home/runner/work/go-capnproto2/go-capnproto2/rpc/question.go:182 +0x4e
capnproto.org/go/capnp/v3/rpc.TestCallReceiverAnswerRpc(0x8c97770)
/home/runner/work/go-capnproto2/go-capnproto2/rpc/receiveranswer_test.go:137 +0x583
testing.tRunner(0x8c97770, 0x82e0b2c)
/opt/hostedtoolcache/go/1.19.3/x64/src/testing/testing.go:1446 +0x113
created by testing.(*T).Run
/opt/hostedtoolcache/go/1.19.3/x64/src/testing/testing.go:1493 +0x374
exit status 2
FAIL capnproto.org/go/capnp/v3/rpc 0.115s
Error: Process completed with exit code 1.
Per discussion on matrix: I am having a really hard time reproducing this, and it seems likely that #366 could have fixed this as well given the nature of the change (though I'm having a hard time reproducing it locally before that commit too). I'm going to close this one for now; we can re-open if we see it again, but otherwise this seems likely to turn into a wild goose chase.
Re-opening; I just hit this again locally. I wasn't able to reproduce it a second time (ran the tests 700 times), but now we have some evidence that this is still there, and just incredibly rare.
Is there any chance this might have been resolved by #396 or #406 ? I ask because this issue doesn't feel very actionable, and I would very much like an excuse to close it! 😅
If not, is there a low-effort approach we could take to flushing it out, e.g. running unit tests a few thousand times on a dev machine?
Assuming we can't reproduce it, how do you feel about closing optimistically?
I'm ok closing it until it comes up again.
I hit this again, re-opening. The stack trace below starts in a different spot, but still ends in Client.Release, so that gives me some confidence that this isn't terribly specific to any one test, and is a more general bug with the way Clients work.
panic: close of closed channel
goroutine 3094 [running]:
capnproto.org/go/capnp/v3.Client.Release({0x73be20?})
/home/isd/src/go-wk/go-capnproto2/capability.go:589 +0x167
capnproto.org/go/capnp/v3.(*Message).Reset(0xc00061bcc0, {0x0?, 0x0})
/home/isd/src/go-wk/go-capnproto2/message.go:141 +0x12c
capnproto.org/go/capnp/v3/rpc/transport.(*transport).RecvMessage.func1()
/home/isd/src/go-wk/go-capnproto2/rpc/transport/transport.go:172 +0x2f
capnproto.org/go/capnp/v3/rpc.(*Conn).handleReturn.func1.2()
/home/isd/src/go-wk/go-capnproto2/rpc/rpc.go:1130 +0x142
created by capnproto.org/go/capnp/v3/rpc.(*Conn).handleReturn.func1
/home/isd/src/go-wk/go-capnproto2/rpc/rpc.go:1122 +0x837
exit status 2
FAIL capnproto.org/go/capnp/v3/rpc 0.252s