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go/misc/cgo/testplugin/testdata/issue18676/main.go
Bryan C. Mills eb2d1cdd1b misc/cgo/testplugin: convert test.bash to Go and fix in module mode
Updates #30228
Updates #28387

Change-Id: Iad7d960b70221f90ccc2372bb1d4d41cec3926e4
Reviewed-on: https://go-review.googlesource.com/c/163214
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2019-02-24 00:36:13 +00:00

32 lines
1.1 KiB
Go

// 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.
// The bug happened like this:
// 1) The main binary adds an itab for *json.UnsupportedValueError / error
// (concrete type / interface type). This itab goes in hash bucket 0x111.
// 2) The plugin adds that same itab again. That makes a cycle in the itab
// chain rooted at hash bucket 0x111.
// 3) The main binary then asks for the itab for *dynamodbstreamsevt.Event /
// json.Unmarshaler. This itab happens to also live in bucket 0x111.
// The lookup code goes into an infinite loop searching for this itab.
// The code is carefully crafted so that the two itabs are both from the
// same bucket, and so that the second itab doesn't exist in
// the itab hashmap yet (so the entire linked list must be searched).
package main
import (
"encoding/json"
"plugin"
"testplugin/issue18676/dynamodbstreamsevt"
)
func main() {
plugin.Open("plugin.so")
var x interface{} = (*dynamodbstreamsevt.Event)(nil)
if _, ok := x.(json.Unmarshaler); !ok {
println("something")
}
}