Bug 2073113: do not report docker conf deprecation warning when the d…

…ocker is not available

pkg/cli/image/manifest/dockercredentials/auth_resolver.go

@@ -50,12 +50,18 @@ func NewAuthResolver(authFilePath string) (*AuthResolver, error) {
 		if err != nil {
 			return nil, err
 		}
-		if image.GetRegistryAuthConfigPreference() == image.DockerPreference {
-			// give priority to the docker config file $HOME/.docker/config.json
-			for registry, entry := range defaultClientDockerConfig() {
-				credentials[registry] = containertypes.DockerAuthConfig{
-					Username: entry.Username,
-					Password: entry.Password,
+		if pref, warn := image.GetRegistryAuthConfigPreference(); pref == image.DockerPreference {
+			config := defaultClientDockerConfig()
+			if config != nil {
+				if len(warn) > 0 {
+					fmt.Fprint(os.Stderr, warn)
+				}
+				// give priority to the docker config file $HOME/.docker/config.json
+				for registry, entry := range config {
+					credentials[registry] = containertypes.DockerAuthConfig{
+						Username: entry.Username,
+						Password: entry.Password,
+					}
 				}
 			}
 
@@ -165,7 +171,7 @@ func defaultClientDockerConfig() credentialprovider.DockerConfig {
 	if cfg, err := credentialprovider.ReadDockercfgFile(defaultPathsForLegacyCredentials()); err == nil {
 		return cfg
 	}
-	return credentialprovider.DockerConfig{}
+	return nil
 }
 
 // defaultPathsForCredentials returns the correct search directories for a docker config

pkg/cli/registry/login/login.go

@@ -242,7 +242,10 @@ func (o *LoginOptions) Complete(f kcmdutil.Factory, args []string) error {
 	if len(o.ConfigFile) == 0 {
 		if authFile := os.Getenv("REGISTRY_AUTH_FILE"); authFile != "" {
 			o.ConfigFile = authFile
-		} else if image.GetRegistryAuthConfigPreference() == image.DockerPreference {
+		} else if pref, warn := image.GetRegistryAuthConfigPreference(); pref == image.DockerPreference {
+			if len(warn) > 0 {
+				fmt.Fprint(o.IOStreams.ErrOut, warn)
+			}
 			home := homedir.HomeDir()
 			o.ConfigFile = filepath.Join(home, ".docker", "config.json")
 		}

pkg/helpers/image/helpers.go

@@ -1,7 +1,6 @@
 package image
 
 import (
-	"fmt"
 	"os"
 	"strings"
 
@@ -141,14 +140,15 @@ var (
 	PodmanPreference RegistryAuthConfigPreference = "podman"
 )
 
-func GetRegistryAuthConfigPreference() RegistryAuthConfigPreference {
+func GetRegistryAuthConfigPreference() (RegistryAuthConfigPreference, string) {
 	// TODO: docker default is deprecated and will be changed to podman in 4.12
 	result := DockerPreference // default to docker
+	warning := ""
 	if authPreference := strings.ToLower(os.Getenv("REGISTRY_AUTH_PREFERENCE")); authPreference == string(DockerPreference) || authPreference == string(PodmanPreference) {
 		result = RegistryAuthConfigPreference(authPreference)
 	} else {
 		// TODO: remove once deprecated in 4.12
-		fmt.Fprintf(os.Stderr, "Warning: the default reading order of registry auth file will be changed from \"${HOME}/.docker/config.json\" to podman registry config locations in the future version. \"${HOME}/.docker/config.json\" is deprecated, but can still be used for storing credentials as a fallback. See https://github.com/containers/image/blob/main/docs/containers-auth.json.5.md for the order of podman registry config locations.\n")
+		warning = "Warning: the default reading order of registry auth file will be changed from \"${HOME}/.docker/config.json\" to podman registry config locations in the future version. \"${HOME}/.docker/config.json\" is deprecated, but can still be used for storing credentials as a fallback. See https://github.com/containers/image/blob/main/docs/containers-auth.json.5.md for the order of podman registry config locations.\n"
 	}
-	return result
+	return result, warning
 }