Golang Defer可以对调用者/外部函数起作用？

Question

Is it possible to defer to the end of an outer function?

// normal transaction
func dbStuff(){
    db.Begin()
    ...
    db.Commit()
}

// normal transaction w/ defer
func dbStuff(){
    db.Begin()
    defer db.Commit()
    ...
}

Is this possible?

// can you defer to caller / outer function?
func dbStuff(){
    db.Trans()
    ...
}

// will Commit() when dbStuff() returns
func (db Db) Trans(){
    db.Begin()
    defer db.Commit() // to caller/outer function
}

Answer 1

According to the specification, it's not possible:

A "defer" statement invokes a function whose execution is deferred to the moment the surrounding function returns, either because the surrounding function executed a return statement, reached the end of its function body, or because the corresponding goroutine is panicking.

(emphasis mine)

Update: Apart from that, it would not be a good idea either – one of the strengths of Go is "what you see is what you get". Deferring functions from inner functions to outer functions would create 'invisible' changes in your control flow.