Fix the converts an empty string to nil.

[HirazawaUi]

What type of PR is this?

/kind bug

What this PR does / why we need it:

converter shouldn't transform a "" into a []byte(nil) but into a []byte{}

Which issue(s) this PR fixes:

Fixes #118588

Special notes for your reviewer:

For the detailed discussion, please refer to: #118605 (comment)

Does this PR introduce a user-facing change?

NONE

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[k8s-ci-robot]

Hi @HirazawaUi. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[HirazawaUi]

@wojtek-t @thockin @apelisse Please help review this PR

[wojtek-t]

This LGTM, but I will let @apelisse to also take a look.

/approve

/assign @apelisse

[wojtek-t]

/ok-to-test

[apelisse]

I'm not convinced this is good enough? Did that test fail to pass without the change?

[HirazawaUi]

I'm not convinced this is good enough? Did that test fail to pass without the change?

This test will fails without the change, The error message is as follows:

    converter_test.go:691: Object changed, diff:   &runtime_test.F{
          	... // 7 identical fields
          	H: nil,
          	I: nil,
        - 	J: []uint8{},
        + 	J: nil,
          }

[alexzielenski]

/triage accepted

[thockin]

Thanks for the follow-through @HirazawaUi - this has been a fun bug to track. After this PR, is the secret issue resolved? If so, we should still add a test case for it. If not, ...uh oh?

I also approve, but @apelisse holds the LGTM.

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: HirazawaUi, thockin, wojtek-t

The full list of commands accepted by this bot can be found here.

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Needs approval from an approver in each of these files:

• staging/src/k8s.io/apimachinery/pkg/OWNERS [thockin,wojtek-t]

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[HirazawaUi]

Thanks for the follow-through @HirazawaUi - this has been a fun bug to track. After this PR, is the secret issue resolved? If so, we should still add a test case for it. If not, ...uh oh?

I also approve, but @apelisse holds the LGTM.

/approve

Yes, the secret issue is solved.

[apelisse]

Thanks
/lgtm

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 4fcabdc474499726aa407c2143aa83e159e3d1f9

[pacoxu]

The failure is a flake #119244.

/test pull-kubernetes-unit

[wojtek-t]

/retest

[rfranzke]

Thank you @HirazawaUi! Do you plan to cherry-pick this PR?

[HirazawaUi]

Thank you @HirazawaUi! Do you plan to cherry-pick this PR?

Okay, I'll do this.