A linter to enforce importing certain packages consistently.

Ideally, go imports should avoid aliasing. Sometimes though, especially with Kubernetes API code, it becomes unavoidable, because many packages are imported as e.g. "[package]/v1alpha1" and you end up with lots of collisions if you use "v1alpha1".

This linter lets you enforce that whenever (for example) "pkg/apis/serving/v1alpha1" is aliased, it is aliased as "servingv1alpha1".

importas \
  -alias knative.dev/serving/pkg/apis/autoscaling/v1alpha1:autoscalingv1alpha1 \
  -alias knative.dev/serving/pkg/apis/serving/v1:servingv1 \
  ./...

By default, importas allows non-aliased imports, even when the package is specified by -alias flag. With -no-unaliased option, importas does not allow this.

importas -no-unaliased \
  -alias knative.dev/serving/pkg/apis/autoscaling/v1alpha1:autoscalingv1alpha1 \
  -alias knative.dev/serving/pkg/apis/serving/v1:servingv1 \
  ./...

By default, importas allows aliases which are not specified by -alias flags. With -no-extra-aliases option, importas does not allow any unspecified aliases.

importas -no-extra-aliases \
  -alias knative.dev/serving/pkg/apis/autoscaling/v1alpha1:autoscalingv1alpha1 \
  -alias knative.dev/serving/pkg/apis/serving/v1:servingv1 \
  ./...

You can specify the package path by regular expression, and alias by regular expression replacement syntax like following snippet.

importas -alias 'knative.dev/serving/pkg/apis/(\w+)/(v[\w\d]+):$1$2'

$1 represents the text of the first submatch. See detail.

So it will enforce that

"knative.dev/serving/pkg/apis/autoscaling/v1alpha1" is aliased by "autoscalingv1alpha1", and "knative.dev/serving/pkg/apis/serving/v1" is aliased by "servingv1"