net: LookupAddr does not set IsNotFound with cgo resolver #57548
Description
What version of Go are you using (go version)?
$ go version go version go1.19.4 linux/amd64
Does this issue reproduce with the latest release?
Yes
What operating system and processor architecture are you using (go env)?
go env Output
GO111MODULE="" GOARCH="amd64" GOBIN="" GOCACHE="$HOME/.cache/go-build" GOENV="$HOME/.config/go/env" GOEXE="" GOEXPERIMENT="" GOFLAGS="" GOHOSTARCH="amd64" GOHOSTOS="linux" GOINSECURE="" GOMODCACHE="$HOME/dev/go/pkg/mod" GONOPROXY="" GONOSUMDB="" GOOS="linux" GOPRIVATE="" GOPROXY="https://proxy.golang.org,direct" GOROOT="/opt/go/go1.19.4" GOSUMDB="sum.golang.org" GOTMPDIR="" GOTOOLDIR="/opt/go/go1.19.4/pkg/tool/linux_amd64" GOVCS="" GOVERSION="go1.19.4" GCCGO="gccgo" GOAMD64="v1" AR="ar" CC="gcc" CXX="g++" CGO_ENABLED="1" GOMOD="/dev/null" GOWORK="" CGO_CFLAGS="-g -O2" CGO_CPPFLAGS="" CGO_CXXFLAGS="-g -O2" CGO_FFLAGS="-g -O2" CGO_LDFLAGS="-g -O2" PKG_CONFIG="pkg-config" GOGCCFLAGS="-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -fdebug-prefix-map=/run/user/$UID/go-build1957738364=/tmp/go-build -gno-record-gcc-switches"
What did you do?
$ cat > x.go <<EOF
package main
import (
"fmt"
"net"
)
func main() {
_, err := net.LookupAddr("1.2.3.4")
fmt.Printf("%v\n", err.(*net.DNSError).IsNotFound)
}
EOF
$ GODEBUG=netdns=go go run x.go
true
$ GODEBUG=netdns=cgo go run x.go
false
What did you expect to see?
Both go and cgo resolver correctly report IsNotFound.
What did you see instead?
Only go resolver does so.
There's already a pull request for this but it wasn't merged: #45959