4 files changed, 21 insertions, 17 deletions
diff --git a/cmd/podman/cliconfig/config.go b/cmd/podman/cliconfig/config.go
index 5b5225f02..4831b7971 100644
--- a/cmd/podman/cliconfig/config.go
+++ b/cmd/podman/cliconfig/config.go
@@ -651,6 +651,7 @@ type SystemRenumberValues struct {
 
 type SystemMigrateValues struct {
 	PodmanCommand
+	NewRuntime string
 }
 
 type SystemDfValues struct {
diff --git a/cmd/podman/images.go b/cmd/podman/images.go
index fe7c89b5c..e363fa3bb 100644
--- a/cmd/podman/images.go
+++ b/cmd/podman/images.go
@@ -216,17 +216,18 @@ func (i imagesOptions) setOutputFormat() string {
 }
 
 // imagesToGeneric creates an empty array of interfaces for output
-func imagesToGeneric(templParams []imagesTemplateParams, JSONParams []imagesJSONParams) (genericParams []interface{}) {
+func imagesToGeneric(templParams []imagesTemplateParams, JSONParams []imagesJSONParams) []interface{} {
+	genericParams := []interface{}{}
 	if len(templParams) > 0 {
 		for _, v := range templParams {
 			genericParams = append(genericParams, interface{}(v))
 		}
-		return
+		return genericParams
 	}
 	for _, v := range JSONParams {
 		genericParams = append(genericParams, interface{}(v))
 	}
-	return
+	return genericParams
 }
 
 func sortImagesOutput(sortBy string, imagesOutput imagesSorted) imagesSorted {
@@ -309,7 +310,8 @@ func getImagesTemplateOutput(ctx context.Context, images []*adapter.ContainerIma
 }
 
 // getImagesJSONOutput returns the images information in its raw form
-func getImagesJSONOutput(ctx context.Context, images []*adapter.ContainerImage) (imagesOutput []imagesJSONParams) {
+func getImagesJSONOutput(ctx context.Context, images []*adapter.ContainerImage) []imagesJSONParams {
+	imagesOutput := []imagesJSONParams{}
 	for _, img := range images {
 		size, err := img.Size(ctx)
 		if err != nil {
@@ -325,7 +327,7 @@ func getImagesJSONOutput(ctx context.Context, images []*adapter.ContainerImage)
 		}
 		imagesOutput = append(imagesOutput, params)
 	}
-	return
+	return imagesOutput
 }
 
 // generateImagesOutput generates the images based on the format provided
@@ -336,10 +338,6 @@ func generateImagesOutput(ctx context.Context, images []*adapter.ContainerImage,
 
 	switch opts.format {
 	case formats.JSONString:
-		// If 0 images are present, print nothing for JSON
-		if len(images) == 0 {
-			return nil
-		}
 		imagesOutput := getImagesJSONOutput(ctx, images)
 		out = formats.JSONStructArray{Output: imagesToGeneric([]imagesTemplateParams{}, imagesOutput)}
 	default:
diff --git a/cmd/podman/libpodruntime/runtime.go b/cmd/podman/libpodruntime/runtime.go
index 6dafeb0b0..dd8c3f173 100644
--- a/cmd/podman/libpodruntime/runtime.go
+++ b/cmd/podman/libpodruntime/runtime.go
@@ -14,31 +14,31 @@ import (
 )
 
 // GetRuntimeMigrate gets a libpod runtime that will perform a migration of existing containers
-func GetRuntimeMigrate(ctx context.Context, c *cliconfig.PodmanCommand) (*libpod.Runtime, error) {
-	return getRuntime(ctx, c, false, true, false, true)
+func GetRuntimeMigrate(ctx context.Context, c *cliconfig.PodmanCommand, newRuntime string) (*libpod.Runtime, error) {
+	return getRuntime(ctx, c, false, true, false, true, newRuntime)
 }
 
 // GetRuntimeDisableFDs gets a libpod runtime that will disable sd notify
 func GetRuntimeDisableFDs(ctx context.Context, c *cliconfig.PodmanCommand) (*libpod.Runtime, error) {
-	return getRuntime(ctx, c, false, false, false, false)
+	return getRuntime(ctx, c, false, false, false, false, "")
 }
 
 // GetRuntimeRenumber gets a libpod runtime that will perform a lock renumber
 func GetRuntimeRenumber(ctx context.Context, c *cliconfig.PodmanCommand) (*libpod.Runtime, error) {
-	return getRuntime(ctx, c, true, false, false, true)
+	return getRuntime(ctx, c, true, false, false, true, "")
 }
 
 // GetRuntime generates a new libpod runtime configured by command line options
 func GetRuntime(ctx context.Context, c *cliconfig.PodmanCommand) (*libpod.Runtime, error) {
-	return getRuntime(ctx, c, false, false, false, true)
+	return getRuntime(ctx, c, false, false, false, true, "")
 }
 
 // GetRuntimeNoStore generates a new libpod runtime configured by command line options
 func GetRuntimeNoStore(ctx context.Context, c *cliconfig.PodmanCommand) (*libpod.Runtime, error) {
-	return getRuntime(ctx, c, false, false, true, true)
+	return getRuntime(ctx, c, false, false, true, true, "")
 }
 
-func getRuntime(ctx context.Context, c *cliconfig.PodmanCommand, renumber, migrate, noStore, withFDS bool) (*libpod.Runtime, error) {
+func getRuntime(ctx context.Context, c *cliconfig.PodmanCommand, renumber, migrate, noStore, withFDS bool, newRuntime string) (*libpod.Runtime, error) {
 	options := []libpod.RuntimeOption{}
 	storageOpts := storage.StoreOptions{}
 	storageSet := false
@@ -88,6 +88,9 @@ func getRuntime(ctx context.Context, c *cliconfig.PodmanCommand, renumber, migra
 	}
 	if migrate {
 		options = append(options, libpod.WithMigrate())
+		if newRuntime != "" {
+			options = append(options, libpod.WithMigrateRuntime(newRuntime))
+		}
 	}
 
 	if renumber {
diff --git a/cmd/podman/system_migrate.go b/cmd/podman/system_migrate.go
index 4a0afcfad..9c90aeb52 100644
--- a/cmd/podman/system_migrate.go
+++ b/cmd/podman/system_migrate.go
@@ -32,13 +32,15 @@ func init() {
 	migrateCommand.Command = _migrateCommand
 	migrateCommand.SetHelpTemplate(HelpTemplate())
 	migrateCommand.SetUsageTemplate(UsageTemplate())
+	flags := migrateCommand.Flags()
+	flags.StringVar(&migrateCommand.NewRuntime, "new-runtime", "", "Specify a new runtime for all containers")
 }
 
 func migrateCmd(c *cliconfig.SystemMigrateValues) error {
 	// We need to pass one extra option to NewRuntime.
 	// This will inform the OCI runtime to start a migrate.
 	// That's controlled by the last argument to GetRuntime.
-	r, err := libpodruntime.GetRuntimeMigrate(getContext(), &c.PodmanCommand)
+	r, err := libpodruntime.GetRuntimeMigrate(getContext(), &c.PodmanCommand, c.NewRuntime)
 	if err != nil {
 		return errors.Wrapf(err, "error migrating containers")
 	}