Broken change of golang.org/x/sys causes build failed in go1.16

[zhongxinghong]

Question

Current go.mod use go1.16 with golang.org/x/sys v0.0.0-20221010170243-090e33056c14 package which introduced go1.17's unsafe.Slice in 20220910 (see history https://cs.opensource.google/go/x/sys/+/master:unix/syscall.go;bpv=1). This will cause build failed in go1.16 with following error messges.

# golang.org/x/sys/unix
../compile_path/pkg/mod/golang.org/x/[email protected]/unix/syscall.go:83:16: undefined: unsafe.Slice
../compile_path/pkg/mod/golang.org/x/[email protected]/unix/syscall_linux.go:2255:9: undefined: unsafe.Slice
../compile_path/pkg/mod/golang.org/x/[email protected]/unix/syscall_unix.go:118:7: undefined: unsafe.Slice
../compile_path/pkg/mod/golang.org/x/[email protected]/unix/sysvshm_unix.go:33:7: undefined: unsafe.Slice
note: module requires Go 1.17

[zhangyunhao116]

I can't reproduce this error, could you list a more detailed reproduction process? thanks!

My steps:

> go version
go version go1.16.15 linux/amd64
> git clone https://github.com/bytedance/gopkg.git && cd gopkg && go test ./...
go: downloading golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
go: downloading github.com/stretchr/testify v1.7.0
go: downloading golang.org/x/sys v0.0.0-20221010170243-090e33056c14
go: downloading gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c
go: downloading github.com/davecgh/go-spew v1.1.0
ok      github.com/bytedance/gopkg/cache/asynccache     6.819s
ok      github.com/bytedance/gopkg/cloud/circuitbreaker 18.233s
ok      github.com/bytedance/gopkg/cloud/metainfo       0.002s
ok      github.com/bytedance/gopkg/collection/hashset   0.121s
ok      github.com/bytedance/gopkg/collection/lscq      0.361s
ok      github.com/bytedance/gopkg/collection/skipmap   0.348s
ok      github.com/bytedance/gopkg/collection/skipset   0.132s
ok      github.com/bytedance/gopkg/collection/zset      0.029s
?       github.com/bytedance/gopkg/internal/benchmark/linkedq   [no test files]
?       github.com/bytedance/gopkg/internal/benchmark/msq       [no test files]
?       github.com/bytedance/gopkg/internal/hack        [no test files]
ok      github.com/bytedance/gopkg/internal/runtimex    0.002s
ok      github.com/bytedance/gopkg/internal/wyhash      0.205s
ok      github.com/bytedance/gopkg/lang/fastrand        0.028s
ok      github.com/bytedance/gopkg/lang/mcache  0.002s
ok      github.com/bytedance/gopkg/lang/stringx 0.002s
ok      github.com/bytedance/gopkg/lang/syncx   0.116s
ok      github.com/bytedance/gopkg/util/gctuner 0.025s
ok      github.com/bytedance/gopkg/util/gopool  0.015s
?       github.com/bytedance/gopkg/util/logger  [no test files]
ok      github.com/bytedance/gopkg/util/xxhash3 0.369s
?       github.com/bytedance/gopkg/util/xxhash3/internal/xxh3_raw       [no test files]

[zhongxinghong]

This is because bytedance/gopkg doesn't depend on golang.org/x/sys/unix. Let's create a package that depends on it then you will see the problem:

1. setup

$ /usr/local/go1.16.15/bin/go version
go version go1.16.15 linux/amd64
$ mkdir -p ~/go/src/test/issue163 && cd ~/go/src/test/issue163
$ touch go.mod
$ touch main.go

2. create main.go

//go:build linux
// +build linux

package main

import (
    "github.com/bytedance/gopkg/util/gopool"
    "golang.org/x/sys/unix"
)

func main() {
    _ = gopool.NewPool
    _ = unix.Fadvise
}

3. create go.mod

module test/issue163

go 1.16

4. go mod tidy

$ /usr/local/go1.16.15/bin/go mod tidy
go: finding module for package golang.org/x/sys/unix
go: finding module for package github.com/bytedance/gopkg/util/gopool
go: found github.com/bytedance/gopkg/util/gopool in github.com/bytedance/gopkg v0.0.0-20221122125632-68358b8ecec6
go: found golang.org/x/sys/unix in golang.org/x/sys v0.3.0

after current step our go.mod will look like this:

module test/issue163

go 1.16

require (
    github.com/bytedance/gopkg v0.0.0-20221122125632-68358b8ecec6
    golang.org/x/sys v0.3.0
)

5. go build

$ /usr/local/go1.16.15/bin/go build
# golang.org/x/sys/unix
../../../pkg/mod/golang.org/x/[email protected]/unix/syscall.go:83:16: undefined: unsafe.Slice
../../../pkg/mod/golang.org/x/[email protected]/unix/syscall_linux.go:2256:9: undefined: unsafe.Slice
../../../pkg/mod/golang.org/x/[email protected]/unix/syscall_unix.go:118:7: undefined: unsafe.Slice
../../../pkg/mod/golang.org/x/[email protected]/unix/sysvshm_unix.go:33:7: undefined: unsafe.Slice
note: module requires Go 1.17

6. downgrade golang.org/x/sys and test it again

• modify our go.mod

module test/issue163

go 1.16

require (
    github.com/bytedance/gopkg v0.0.0-20221122125632-68358b8ecec6
    golang.org/x/sys v0.0.0-20220110181412-a018aaa089fe
)

NOTE: a commonly used library in ByteDance use golang.org/x/sys v0.0.0-20220110181412-a018aaa089fe

• go mod tidy

$ /usr/local/go1.16.15/bin/go mod tidy

then our go.mod will look like this:

module test/issue163

go 1.16

require (
    github.com/bytedance/gopkg v0.0.0-20221122125632-68358b8ecec6
    golang.org/x/sys v0.0.0-20221010170243-090e33056c14
)

the version of golang.org/x/sys will be changed to v0.0.0-20221010170243-090e33056c14 since bytedance/gopkg choose it.

• go build

$ /usr/local/go1.16.15/bin/go build
# golang.org/x/sys/unix
../../../pkg/mod/golang.org/x/[email protected]/unix/syscall.go:83:16: undefined: unsafe.Slice
../../../pkg/mod/golang.org/x/[email protected]/unix/syscall_linux.go:2255:9: undefined: unsafe.Slice
../../../pkg/mod/golang.org/x/[email protected]/unix/syscall_unix.go:118:7: undefined: unsafe.Slice
../../../pkg/mod/golang.org/x/[email protected]/unix/sysvshm_unix.go:33:7: undefined: unsafe.Slice
note: module requires Go 1.17