make rolling update check if the replication controller has been defaulted

pkg/kubectl/cmd/rollingupdate.go

@@ -26,6 +26,8 @@ import (
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/errors"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/v1"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/v1beta3"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubectl"
 	cmdutil "github.com/GoogleCloudPlatform/kubernetes/pkg/kubectl/cmd/util"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubectl/resource"
@@ -143,6 +145,7 @@ func RunRollingUpdate(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, arg
 	}
 
 	var keepOldName bool
+	var replicasDefaulted bool
 
 	mapper, typer := f.Object()
 
@@ -151,12 +154,12 @@ func RunRollingUpdate(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, arg
 		if err != nil {
 			return err
 		}
-		obj, err := resource.NewBuilder(mapper, typer, f.ClientMapperForCommand()).
+		request := resource.NewBuilder(mapper, typer, f.ClientMapperForCommand()).
 			Schema(schema).
 			NamespaceParam(cmdNamespace).RequireNamespace().
 			FilenameParam(filename).
-			Do().
-			Object()
+			Do()
+		obj, err := request.Object()
 		if err != nil {
 			return err
 		}
@@ -177,6 +180,12 @@ func RunRollingUpdate(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, arg
 			glog.V(4).Infof("Object %#v is not a ReplicationController", obj)
 			return cmdutil.UsageError(cmd, "%s does not specify a valid ReplicationController", filename)
 		}
+		infos, err := request.Infos()
+		if err != nil || len(infos) != 1 {
+			glog.V(2).Infof("was not able to recover adequate information to discover if .spec.replicas was defaulted")
+		} else {
+			replicasDefaulted = isReplicasDefaulted(infos[0])
+		}
 	}
 	// If the --image option is specified, we need to create a new rc with at least one different selector
 	// than the old rc. This selector is the hash of the rc, which will differ because the new rc has a
@@ -228,7 +237,7 @@ func RunRollingUpdate(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, arg
 			filename, oldName)
 	}
 	// TODO: handle scales during rolling update
-	if newRc.Spec.Replicas == 0 {
+	if replicasDefaulted {
 		newRc.Spec.Replicas = oldRc.Spec.Replicas
 	}
 	if dryrun {
@@ -283,3 +292,21 @@ func findNewName(args []string, oldRc *api.ReplicationController) string {
 	}
 	return ""
 }
+
+func isReplicasDefaulted(info *resource.Info) bool {
+	if info == nil || info.VersionedObject == nil {
+		// was unable to recover versioned info
+		return false
+	}
+	switch info.Mapping.APIVersion {
+	case "v1":
+		if rc, ok := info.VersionedObject.(*v1.ReplicationController); ok {
+			return rc.Spec.Replicas == nil
+		}
+	case "v1beta3":
+		if rc, ok := info.VersionedObject.(*v1beta3.ReplicationController); ok {
+			return rc.Spec.Replicas == nil
+		}
+	}
+	return false
+}