mirror of
https://github.com/golang/go
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59 lines
948 B
Go
59 lines
948 B
Go
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// run
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// Copyright 2019 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Issue 31419: race in getitab when two goroutines try
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// to do the same failed interface conversion.
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package main
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type T int
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func (t T) M() {}
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type I interface {
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M()
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M2()
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}
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var t T
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var e interface{} = &t
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var ok = false
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var ch = make(chan int)
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func main() {
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_, ok = e.(I) // populate itab cache with a false result
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go f() // get itab in a loop
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var i I
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for k := 0; k < 10000; k++ {
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i, ok = e.(I) // read the cached itab
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if ok {
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println("iteration", k, "i =", i, "&t =", &t)
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panic("conversion succeeded")
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}
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}
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<-ch
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}
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func f() {
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for i := 0; i < 10000; i++ {
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f1()
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}
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ch <- 1
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}
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func f1() {
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defer func() {
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err := recover()
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if err == nil {
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panic("did not panic")
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}
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}()
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i := e.(I) // triggers itab.init, for getting the panic string
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_ = i
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}
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