kubectl --sort-by not working in 1.7.0

[fiksn]

Is this a BUG REPORT or FEATURE REQUEST? (choose one):
bug report

Kubernetes version (use kubectl version):
Client Version: version.Info{Major:"1", Minor:"7", GitVersion:"v1.7.0", GitCommit:"d3ada0119e776222f11ec7945e6d860061339aad", GitTreeState:"clean", BuildDate:"2017-06-29T23:15:59Z", GoVersion:"go1.8.3", Compiler:"gc", Platform:"darwin/amd64"}
Server Version: version.Info{Major:"1", Minor:"7", GitVersion:"v1.7.0", GitCommit:"d3ada0119e776222f11ec7945e6d860061339aad", GitTreeState:"clean", BuildDate:"2017-06-29T22:55:19Z", GoVersion:"go1.8.3", Compiler:"gc", Platform:"linux/amd64"}

Environment:
Kubernetes cluster is running on CoreOS

VERSION=1409.5.0
VERSION_ID=1409.5.0
BUILD_ID=2017-06-22-2222
PRETTY_NAME="Container Linux by CoreOS 1409.5.0 (Ladybug)"

Kernel 4.11.6-coreos-r1, but that should be pretty irrelevant as it seems the problem is in kubectl.
Tried on MacOS 10.12.5 with 1.7.0 kubectl and on various GNU/Linux machines. It doesn't work also against a 1.6.6 Kubernetes cluster so I am quite confident this is a client issue.

What happened:
$ kubectl get pods --sort-by='{.metadata.name}'
error: unknown type api.Pod, expected unstructured in map[reflect.Type]printers.handlerEntry{}

What you expected to happen:
A list of pods sorted by name should have appeared as was the case with 1.6.6.

[mengqiy]

/assign @shiywang
Do you have bandwidth to look into this?

[shiywang]

@mengqiy sure

[shiywang]

already found the root cause, will submit a patch soon