go runtime_error ai_generated true

fatal error: all goroutines are asleep - deadlock! (goroutine 1 [select (no cases))])

ID: go/select-on-nil-channel

Also available as: JSON · Markdown · 中文
80%Fix Rate
86%Confidence
0Evidence
2024-09-14First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
1.19 active — — —
1.22 active — — —

Root Cause

A select statement with all nil channels blocks forever because nil channels are never ready.

generic

中文

所有通道都是 nil 的 select 语句会永远阻塞，因为 nil 通道永远不会就绪。

Workarounds

  1. 95% success 
    ch1 := make(chan int)
ch2 := make(chan int)
select {
case v := <-ch1:
    //
case v := <-ch2:
    //
}
  2. 90% success 
    select {
case v := <-ch:
    //
case <-time.After(time.Second):
    // timeout
}

Dead Ends

Common approaches that don't work:

  1. 70% fail

    Default case may execute incorrectly and not handle the intended communication.

  2. 90% fail

    Sleeping doesn't resolve the block; the select still blocks.