Not all os/error's handled in syscall.Errno.Is

[oncecreated]

What version of Go are you using (go version)?

$ go version
go version go1.13.4 linux/amd64

Does this issue reproduce with the latest release?

Yes, there no changes.

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/user1/.cache/go-build"
GOENV="/home/user1/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/user1/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/lib/go-1.13"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/go-1.13/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build325102545=/tmp/go-build -gno-record-gcc-switches"

What did you do?

Recommendation from https://golang.org/src/syscall/syscall_unix.go?s=2815:2833#L115 , use errors.Is, while checking error from syscall. But some os.Err*, not handled in syscall.Errno.Is. In the example I try to check for os.ErrInvalid, and always get false. I think it's little obscure, all errors defined in os/errors.go need be check.

package main

import (
    "syscall"
    "net"
    "log"
    "errors"
    "os"
)

const TCP_FASTOPEN_CONNECT = 30

func main() {
    addr, err := net.ResolveTCPAddr("tcp", "127.0.0.1:1337")
    if err != nil {
        log.Fatal(err)
    }
    li, err := net.ListenTCP("tcp", addr)
    if err != nil {
        log.Fatal(err)
    }
    conn, err := li.SyscallConn()
    if err != nil {
        log.Fatal(err)
    }
    conn.Control(func(fd uintptr) {
        err = syscall.SetsockoptInt(int(fd), syscall.SOL_TCP, TCP_FASTOPEN_CONNECT, 5)
        if errors.Is(err, os.ErrInvalid) {
            log.Fatal("true ", err)
        } else {
            log.Fatal("false ", err) // false "invalid argument", the same as os.ErrInvalid
        }
    })
}

What did you expect to see?

Actual check with:

if errors.Is(err, os.ErrInvalid) {
}

What did you see instead?

Always false.

[bcmills]

See also #30322.

[dmitshur]

Based on the title of this issue, it seems the same as the one Bryan linked above.

Should we close this issue in favor of the existing one? Or should we make this issue more specific to a single case?

[oncecreated]

Yeah, I think it's related.