Description

ko uses "go" as GOROOT when GOROOT is not exported in the environment, instead of defaulting to $(go env GOROOT). This prevents builds from happening.

In the previous version, the error message was quite explicit: "go: cannot find GOROOT directory: go".

Now, in 0.6.0, the error is much more ambiguous: importpath "ko://knative.dev/serving/cmd/controller" is not supported.

ko version

$ ko  version
0.6.0

How to reproduce

Example, inside https://github.com/knative/serving/

$ printenv GOROOT  # empty

$ ko publish -L ./cmd/controller  # failure
2020/10/07 12:41:33 failed to publish images: importpath "ko://knative.dev/serving/cmd/controller" is not supported

$ export GOROOT="$(go env GOROOT)"

$ printenv GOROOT
/usr/local/go

$ ko publish -L ./cmd/controller  # success
2020/10/07 12:45:13 Using base gcr.io/distroless/static:nonroot for knative.dev/serving/cmd/controller
2020/10/07 12:45:15 Building knative.dev/serving/cmd/controller for linux/amd64
[...]

Temporary workaround

Add this line to your .*shrc file:

export GOROOT="${GOROOT:-$(go env GOROOT)}"