kubernetes: main module (k8s.io/kubernetes) does not contain package k8s.io/kubernetes/hack/tools/ncpu

What happened?

I am not able to run tests through make rules if the repo isn’t located under $GOPATH/src/k8s.io.

❯ make test GOFLAGS="-v -failfast -count=1" KUBE_COVER="y" WHAT=./pkg/kubelet/kuberuntime
main module (k8s.io/kubernetes) does not contain package k8s.io/kubernetes/hack/tools/ncpu
!!! [0414 17:10:00] Call tree:
!!! [0414 17:10:00]  1: hack/make-rules/test.sh:24 kube::golang::setup_env(...)
make: *** [Makefile:184: test] Error

What did you expect to happen?

Run unit tests for pkg/kubelet/kuberuntime.

How can we reproduce it (as minimally and precisely as possible)?

❯ pwd
/Users/thomasmilox/perso/kubernetes

❯ go version
go version go1.20.3 darwin/amd64

❯ make test GOFLAGS="-v -failfast -count=1" KUBE_COVER="y" WHAT=./pkg/kubelet/kuberuntime
main module (k8s.io/kubernetes) does not contain package k8s.io/kubernetes/hack/tools/ncpu
!!! [0414 17:10:00] Call tree:
!!! [0414 17:10:00]  1: hack/make-rules/test.sh:24 kube::golang::setup_env(...)
make: *** [Makefile:184: test] Error

Anything else we need to know?

To solve the issue I had to:

❯ go get k8s.io/kubernetes/hack/tools/ncpu

❯ cd `find $GOPATH -type d -name "ncpu"`

❯ go install .

https://github.com/kubernetes/kubernetes/blob/master/hack/lib/golang.sh#L561-L567

It seems to happen on my setup because of my fork not being located under $GOPATH/src/k8s.io.

Is this worth opening a PR to document it (in development guide for example) ? or we want to enforce people working under $GOPATH/src/k8s.io ?

Kubernetes version

Cloud provider

NONE

OS version

❯ uname -a
Darwin Thomass-MBP 22.3.0 Darwin Kernel Version 22.3.0: Mon Jan 30 20:42:11 PST 2023; root:xnu-8792.81.3~2/RELEASE_X86_64 x86_64 i386 Darwin

Install tools

NONE

Container runtime (CRI) and version (if applicable)

NONE

Related plugins (CNI, CSI, …) and versions (if applicable)

NONE