Go get fails with go 1.13

[jaloren]

1. install go 1.13 on your system
2. cd into a directory that is a go module
3. now run go get

go get k8s.io/client-go@v12.0.0
go: finding k8s.io/client-go v12.0.0
go get k8s.io/client-go@v12.0.0: k8s.io/client-go@v12.0.0: invalid version: module contains a go.mod file, so major version must be compatible: should be v0 or v1, not v12

The issue is that semantic import versioning requires the module declaration to be:

module k8s.io/client-go/v12

[nikhita]

Kubernetes only supports go 1.12 for now. It's a known issue that there are several problems with 1.13, see kubernetes/kubernetes#78845 (comment) for more details.

Closing in favour of kubernetes/kubernetes#78845
/close

[k8s-ci-robot]

@nikhita: Closing this issue.

In response to this:

Kubernetes only supports go 1.12 for now. It's a known issue that there are several problems with 1.13, see kubernetes/kubernetes#78845 (comment) for more details.

Closing in favour of kubernetes/kubernetes#78845
/close

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[BenTheElder]

noting that v11.0.0 will work, but not v12+ due to the go.mod added here

[liggitt]

also updated the install instructions with non-semver tags that will work (even if they resolve to v0.0.0 pseudo versions), rather than complain about non-semantic-import-versioning module names

[carnott-snap]

@jaloren, there is a workaround I found, though it will cause various parts of the go1.13 toolchain to emit logging or errors, signalling that this could just be a bug:

It appears that while go get does not work, a manually curated go.mod file works fine:

module test
  
go 1.13

require k8s.io/client-go v12.0.0+incompatible

package main
  
import (
        "fmt"

        "k8s.io/client-go/pkg/version"
)

func main() { fmt.Println(version.Get()) }

[user@localhost test]$ go run .
go: finding k8s.io/client-go v12.0.0+incompatible
go: finding k8s.io/client-go v12.0.0+incompatible
v0.0.0-master+$Format:%h$
[user@localhost test]$ go build
go: finding k8s.io/client-go v12.0.0+incompatible
go: finding k8s.io/client-go v12.0.0+incompatible
[user@localhost test]$ ./test 
v0.0.0-master+$Format:%h$
[user@localhost test]$ go doc k8s.io/client-go/pkg/version
go: finding k8s.io/client-go v12.0.0+incompatible
go: finding k8s.io/client-go v12.0.0+incompatible
go list -m: k8s.io/client-go@v12.0.0+incompatible: invalid version: +incompatible suffix not allowed: module contains a go.mod file, so semantic import versioning is required
package version // import "k8s.io/client-go/pkg/version"

Package version supplies version information collected at build time to
kubernetes components.

func Get() apimachineryversion.Info

[liggitt]

it's not a bug, go1.13 go stricter about allowing using semver tags >= 2.0 with go modules that did not end with a /v<N> suffix. Using the non-semver tags with go get (see INSTALL.md instructions) works around the issue for now. We're considering how best to support semantic import versioning in these repos.

[carnott-snap]

Sorry if I was unclear. I am familiar with the module version validation changes in go1.13. The potential bug I am referring to is that go get does this validation, but other parts of the toolchain do not, see golang/go#34330.

[liggitt]

The potential bug I am referring to is that go get does this validation, but other parts of the toolchain do not, see golang/go#34330.

oh, got it. I would probably assume that is a bug that will be fixed. Until semantic import versioning is implemented in kubernetes, I'd probably recommend using the kubernetes-1.x.y tags instead.