cmd/go: "go test" needs gcc when importing "net"

[cespedes]

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

$ go version
go version go1.12.9 linux/amd64

Does this issue reproduce with the latest release?

Yes, tested with latest stable version (1.12.9).

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

go env Output

$ go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/cespedes/.cache/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/cespedes/go"
GOPROXY=""
GORACE=""
GOROOT="/usr/lib/go-1.12"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/go-1.12/pkg/tool/linux_amd64"
GCCGO="gccgo"
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 -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build945969099=/tmp/go-build -gno-record-gcc-switches"

What did you do?

$ ls
foo.go
$ cat foo.go 
package foo

import _ "net"
$ go test foo.go 
# runtime/cgo
exec: "gcc": executable file not found in $PATH

"go build" runs without problems, but "go test" needs gcc.

AFAIK, this bug is the same as #27303, but not #26988. Both were closed, but the former is not fixed yet (at least with 1.12.9).

[jingxu97]

Have the similar issue.
Based on #27303, the following works,
export CGO_ENABLED=0

But is this issue really solved?

[iwdgo]

Issue does not occur probably since https://go-review.googlesource.com/c/go/+/335409/
but other changes have occur.
Error now returned for case provided ? command-line-arguments [no test files] which seems appropriate.

[rsc]

I believe this was already fixed, but Go 1.20 will fix this again by automatically disabling cgo if there is no C compiler.