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https://github.com/golang/go
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579c69ac1c
Raising an out-of-bounds panic is confusing. There's no indication that the underlying problem is a race. The runtime already does a pretty good job of detecting this kind of race (modification while iterating). We might as well just reorganize a bit to avoid the out-of-bounds panic. Fixes #33275 Change-Id: Icdd337ad2eb3c84f999db0850ec1d2ff2c146b6e Reviewed-on: https://go-review.googlesource.com/c/go/+/191197 Reviewed-by: Martin Möhrmann <moehrmann@google.com>
35 lines
542 B
Go
35 lines
542 B
Go
// skip
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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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package main
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import (
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"fmt"
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"time"
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)
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func main() {
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// Make a big map.
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m := map[int]int{}
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for i := 0; i < 100000; i++ {
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m[i] = i
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}
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c := make(chan string)
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go func() {
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// Print the map.
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s := fmt.Sprintln(m)
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c <- s
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}()
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go func() {
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time.Sleep(1 * time.Millisecond)
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// Add an extra item to the map while iterating.
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m[-1] = -1
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c <- ""
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}()
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<-c
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<-c
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}
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