Related PR: https://github.com/kubernetes/kubernetes/pull/30313
PR #30313 fixed duplicate errors for invalid aggregate errors in
https://github.com/kubernetes/kubernetes/blob/master/pkg/kubectl/cmd/util/helpers.go
However, duplicate aggregate errors that went through
https://github.com/kubernetes/kubernetes/blob/master/pkg/util/validation/field/errors.go
were not affected by that patch.
This patch adds duplicate aggregate error checking to
`pkg/util/validation/field/errors.go`
\##### Before
`$ kubectl set env rc/idling-echo-1 test-abc=1234`
```
error: ReplicationController "idling-echo-1" is invalid:
[spec.template.spec.containers[0].env[0].name: Invalid value:
"test-abc": must be a C identifier (matching regex
[A-Za-z_][A-Za-z0-9_]*): e.g. "my_name" or "MyName",
spec.template.spec.containers[1].env[0].name: Invalid value: "test-abc":
must be a C identifier (matching regex [A-Za-z_][A-Za-z0-9_]*): e.g.
"my_name" or "MyName", spec.template.spec.containers[0].env[0].name:
Invalid value: "test-abc": must be a C identifier (matching regex
[A-Za-z_][A-Za-z0-9_]*): e.g. "my_name" or "MyName",
spec.template.spec.containers[1].env[0].name: Invalid value: "test-abc":
must be a C identifier (matching regex [A-Za-z_][A-Za-z0-9_]*): e.g.
"my_name" or "MyName"]
```
`$ kubectl set env rc/node-1 test-abc=1234`
```
error: ReplicationController "idling-echo-1" is invalid:
[spec.template.spec.containers[0].env[0].name: Invalid value:
"test-abc": must be a C identifier (matching regex
[A-Za-z_][A-Za-z0-9_]*): e.g. "my_name" or "MyName",
spec.template.spec.containers[1].env[0].name: Invalid value: "test-abc":
must be a C identifier (matching regex [A-Za-z_][A-Za-z0-9_]*): e.g.
"my_name" or "MyName"]
```
\##### After
`$ kubectl set env rc/idling-echo-1 test-abc=1234`
```
error: ReplicationController "idling-echo-1" is invalid:
[spec.template.spec.containers[0].env[0].name: Invalid value:
"test-abc": must be a C identifier (matching regex
[A-Za-z_][A-Za-z0-9_]*): e.g. "my_name" or "MyName",
spec.template.spec.containers[1].env[0].name: Invalid value: "test-abc":
must be a C identifier (matching regex [A-Za-z_][A-Za-z0-9_]*): e.g.
"my_name" or "MyName"]
```
`$ kubectl set env rc/node-1 test-abc=1234`
```
error: ReplicationController "node-1" is invalid:
spec.template.spec.containers[0].env[0].name: Invalid value: "test-abc":
must be a C identifier (matching regex [A-Za-z_][A-Za-z0-9_]*): e.g.
"my_name" or "MyName"
```
I took a hard look at error output and played until I was happier. This now
prints JSON for structs in the error, rather than go's format.
Also made the error message easier to read.
Fixed tests.
deads2k