英文:
How do I handle errors in a deferred function?
问题
func someFunc() (err error) {defer func(err_ error) {handleErrOrPanic(err_, obj)}(err) // 这里的 err 总是 nilerr = ThrowErrOrPanic(ctx, obj)return err}
我想将 handleErrOrPanic 作为延迟函数来处理错误或恐慌。我必须在 ThrowErrOrPanic 之前定义它，因为延迟函数必须处理恐慌。然而，如果我在 err 之前定义它，err 总是为 nil。我该如何解决这个问题？
英文:
func someFunc() (err error) {defer func(err_ error) {r.handleErrOrPanic(err_, obj)}(err) // err is always nil hereerr = ThrowErrOrPanic(ctx, obj)return err}
I would like to use handleErrOrPanic as a deferred function to handle the error or the panic. I have to define it before ThrowErrOrPanic, since the deferred function has to handle the panic. However, if I define it before err is always nil. How do I solve this?
答案1
得分: 2
在延迟函数中使用包围函数的命名返回值，即使用err而不是err_。如果发生恐慌并且你想从中恢复，请在延迟函数中使用recover()。
func someFunc() (err error) {defer func() {if x := recover(); x != nil { // 发生了恐慌？// 处理恐慌} else if err != nil { // 发生了普通错误？// 处理错误} else {// 一切正常}}()err = ThrowErrOrPanic(ctx, obj)return err}
https://go.dev/play/p/miTr-lN1Y9R
英文:
In the deferred func use the named return value of the surrounding function, i.e. use err not err_. If you got panic and you want to recover from it use recover() in the deferred func.
func someFunc() (err error) {defer func() {if x := recover(); x != nil { // panic occurred?// handle panic} else if err != nil { // a plain error occurred?// handle error} else {// all good}}()err = ThrowErrOrPanic(ctx, obj)return err}
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