go runtime_error ai_generated true

WARNING: DATA RACE: Write by goroutine X, Read by goroutine Y (channel send/recv)

ID: go/goroutine-racy-channel-send-recv

Also available as: JSON · Markdown · 中文
80%Fix Rate
86%Confidence
0Evidence
2026-06-30First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
1.0 active — — —
1.20 active — — —

Root Cause

Sending a pointer to a struct via channel, then modifying the struct in sender while receiver reads it.

generic

中文

通过通道发送结构体指针，然后发送者在接收者读取时修改结构体。

Workarounds

  1. 95% success Send value instead of pointer 
    ch := make(chan MyStruct)
go func() {
    s := MyStruct{Field: 42}
    ch <- s // copy of s
}()
s := <-ch
  2. 85% success Use mutex to protect shared struct 
    type Shared struct {
    mu sync.Mutex
    data MyStruct
}
var s Shared
ch := make(chan *Shared)
go func() {
    s.mu.Lock()
    s.data.Field = 42
    s.mu.Unlock()
    ch <- &s
}()

Dead Ends

Common approaches that don't work:

  1. Assuming channel synchronization protects the data 90% fail

    Channel synchronizes the send/recv operation, not the data pointed to.

  2. Copying pointer before send 80% fail

    Copying pointer doesn't deep copy the struct; still shared.