runtime: can't recover

[letian0805]

What version of Go are you using (go version)?

$ go version

Does this issue reproduce with the latest release?

version go1.16

What operating system and processor architecture are you using (go env)?

go env Output

$ go env

What did you do?

package main

import (
    "fmt"
)

func main(){
    defer func() {
        test()
    }() 
    //defer test()  //if add this line, it will work
    panic("test")
}

func test() {
    if err := recover(); err != nil {
        fmt.Println(err)
    }   
}

What did you expect to see?

recovered

What did you see instead?

panic: test

goroutine 1 [running]:
main.main()
/home/letian/work/go/src/test/test.go:11 +0x5b
exit status 2

[seankhliao]

https://pkg.go.dev/builtin#recover

Executing a call to recover inside a deferred function (but not any function called by it) stops the panicking sequence by restoring normal execution and retrieves the error value passed to the call of panic.

Closing as working as intended

[letian0805]

@seankhliao I know how to use recover. Maybe I didn't express it very clearly. In fact, I'm more wondering why it's designed this way. Since the defer function will be executed no matter what, why must it be designed to require recovery in the top-level function of defer to recover from panic? Sometimes this design makes it look more like a bug.

[seankhliao]

see the discussion in #34530

[letian0805]

@seankhliao Thanks!