notation login fails to detect existing credentials for docker.io

[Wwwsylvia]

What is the areas you experience the issue in?

Notation CLI

What is not working as expected?

On a machine without credentials store, after docker login docker.io succeeds, notation login with the same credential should also succeed with a warning.

However, it fails to detect the existing credential and throws an error:

The bug is at here:

notation/cmd/notation/login.go

Lines 118 to 128 in ebfb9ef

	if savedCred, err := credsStore.Get(ctx, registryName); err != nil || savedCred != cred {
	if err != nil {
	// if we fail to get the saved credential, log a warning
	// but do not throw the GET error, as the error could be
	// confusing to users
	logger := log.GetLogger(ctx)
	logger.Warnf("Failed to get the existing credentials for %s: %v", registryName, err)
	}
	return fmt.Errorf("failed to log in to %s: the credential could not be saved because a credentials store is required to securely store the password. See %s",
	registryName, urlDocHowToAuthenticate)
	}

where credsStore.Get() attempts to get the credential for docker.io, while the credential for docker.io is stored in the entry https://index.docker.io/v1/ (expected behavior), hence credsStore.Get("docker.io") returns an empty credential savedCred that does not match the provided credential cred.

A mapping from docker.io to https://index.docker.io/v1/ is required.

What did you expect to happen?

notation login should be able to detect the existing credentials for docker.io

Expected output:

How can we reproduce it?

On a machine without credentials store,

1. Run

docker login docker.io -u $username -p $password

2. Then run

notation login docker.io -u $username -p $password

Describe your environment

Windows 11/powershell

What is the version of your Notation CLI or Notation Library?

Version: 1.0.0-rc.7
Go version: go1.20.4
Git commit: ebfb9ef