go data_error ai_generated true

error：所有 goroutine 看到的是循环变量最终值（i = N）而非各自迭代值

error: all goroutines see final loop variable value (i = N) instead of their iteration value

ID: go/loop-variable-capture-goroutine

其他格式: JSON · Markdown 中文 · English
80%修复率
90%置信度
0证据数
2024-01-10首次发现

版本兼容性

版本状态引入弃用备注
1.16 active — — —
1.20 active — — —
1.22 active — — —

根因分析

在 Go 1.22 之前，循环变量在各迭代间共享。作为 goroutine 启动的闭包捕获同一个变量，运行时其值已推进到最终值。

English

Before Go 1.22, the loop variable is shared across iterations. Closures launched as goroutines capture the same variable, which by the time they run has advanced to the final value.

generic

解决方案

  1. 98% 成功率 
    for i := 0; i < n; i++ {
    i := i
    go func() { use(i) }()
}
  2. 97% 成功率 
    // go.mod: go 1.22
for i := 0; i < n; i++ {
    go func() { use(i) }()
}

无效尝试

常见但无效的做法:

  1. 85% 失败

    Sleeps are not deterministic; the variable is still shared and may advance before the goroutine reads it.

  2. 80% 失败

    Serializing execution does not change variable capture semantics; the final value bug persists.