cmd/go: go test -race can't create $WORK/net.a

[starius]

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

go version go1.8.3 linux/amd64

This go version was compiled from source using make.bash.

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

GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/bnagaev"
GORACE=""
GOROOT="/home/bnagaev/go"
GOTOOLDIR="/home/bnagaev/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build015631019=/tmp/go-build -gno-record-gcc-switches"
CXX="g++"
CGO_ENABLED="1"
PKG_CONFIG="pkg-config"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"

What did you do?

$ go get -t github.com/starius/racesync
$ go test -race github.com/starius/racesync/...
# net
can't create $WORK/net.a: open $WORK/net.a: no such file or directory

Output of go test -x -race github.com/starius/racesync/...
https://gist.github.com/4c41db39b692b8f50ec8bd0d20910b1b

This issue was factored out from #20512 (comment)

[ianlancetaylor]

How repeatable is this for you?

The error message is coming from the compiler. The compiler is saying that it can not create the output file because of a ENOENT error. As far as I can see this can only mean that the directory $WORK does not exist. And that makes no sense at all.

[starius]

I found this error on my machine and then verified it on a clean GCP machine. Both machines run Debian.

[ianlancetaylor]

This is happening because of your test, which is

	dir := os.TempDir()
	defer os.RemoveAll(dir)

The test removes the entire temporary directory while the go tool is using. The failure occurs because the temporary directory is gone when the Go compiler expects it to exist.

Don't do that.

[starius]

Ahhh! I was so stupid doing dir := os.TempDir(). It was intended to create (and remove) a temp directory but instead just removed /tmp.