mirror of
https://github.com/golang/go
synced 2024-11-14 18:40:29 -07:00
dd7cbf3a84
Make sure that when we're assigning to a map, we evaluate the right-hand side before we attempt to insert into the map. We used to evaluate the left-hand side to a pointer-to-slot-in-bucket (which as a side effect does len(m)++), then evaluate the right-hand side, then do the assignment. That clearly isn't correct when the right-hand side might panic. Fixes #22881 Change-Id: I42a62870ff4bf480568c9bdbf0bb18958962bdf0 Reviewed-on: https://go-review.googlesource.com/81817 Reviewed-by: Matthew Dempsky <mdempsky@google.com>
73 lines
1.1 KiB
Go
73 lines
1.1 KiB
Go
// run
|
|
|
|
// Copyright 2017 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
// Test to make sure RHS is evaluated before map insert is started.
|
|
// The RHS panics in all of these cases.
|
|
|
|
package main
|
|
|
|
import "fmt"
|
|
|
|
func main() {
|
|
for i, f := range []func(map[int]int){
|
|
f0, f1, f2, f3, f4, f5, f6, f7,
|
|
} {
|
|
m := map[int]int{}
|
|
func() { // wrapper to scope the defer.
|
|
defer func() {
|
|
recover()
|
|
}()
|
|
f(m) // Will panic. Shouldn't modify m.
|
|
fmt.Printf("RHS didn't panic, case f%d\n", i)
|
|
}()
|
|
if len(m) != 0 {
|
|
fmt.Printf("map insert happened, case f%d\n", i)
|
|
}
|
|
}
|
|
}
|
|
|
|
func f0(m map[int]int) {
|
|
var p *int
|
|
m[0] = *p
|
|
}
|
|
|
|
func f1(m map[int]int) {
|
|
var p *int
|
|
m[0] += *p
|
|
}
|
|
|
|
func f2(m map[int]int) {
|
|
var p *int
|
|
sink, m[0] = sink, *p
|
|
}
|
|
|
|
func f3(m map[int]int) {
|
|
var p *chan int
|
|
m[0], sink = <-(*p)
|
|
}
|
|
|
|
func f4(m map[int]int) {
|
|
var p *interface{}
|
|
m[0], sink = (*p).(int)
|
|
}
|
|
|
|
func f5(m map[int]int) {
|
|
var p *map[int]int
|
|
m[0], sink = (*p)[0]
|
|
}
|
|
|
|
func f6(m map[int]int) {
|
|
var z int
|
|
m[0] /= z
|
|
}
|
|
|
|
func f7(m map[int]int) {
|
|
var a []int
|
|
m[0] = a[0]
|
|
}
|
|
|
|
var sink bool
|