Repository: kubernetes
Issue: code-generator v1.32.x defaulter-gen error
Labels: kind/bug,needs-sig,needs-triage

### What happened?

defaulter-gen  `zz_generated.defaults.go` Content error.

example case: https://github.com/dongjiang1989/customapis/tree/main/pkg/apis/custom/v1 

```yaml
package v1

import (
        corev1 "k8s.io/api/core/v1"
        metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)

// +genclient
// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object

// TestType is a top-level type. A client is created for it.
type TestType struct {
        metav1.TypeMeta `json:",inline"`
        // +optional
        metav1.ObjectMeta `json:"metadata,omitempty"`
        // +optional
        Spec TestSpec `json:"spec,omitempty"`
}

// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object

// TestTypeList is a top-level list type. The client methods for lists are automatically created.
// You are not supposed to create a separated client for this one.
type TestTypeList struct {
        metav1.TypeMeta `json:",inline"`
        // +optional
        metav1.ListMeta `json:"metadata,omitempty"`

        Items []TestType `json:"items"`
}

type TestSpec struct {
        ReplicaSpecs map[string]*ReplicaSpec `json:"replicaSpecs"` --------> this part
}

// +k8s:openapi-gen=true
// +k8s:deepcopy-gen=true
type ReplicaSpec struct {
        // +optional
        Replicas *int32 `json:"replicas,omitempty"`

        Template corev1.PodTemplateSpec `json:"template,omitempty"`
}
````

output:
```yaml
package v1

import (
        corev1 "k8s.io/api/core/v1"                              --------->  This imported package is not required
        runtime "k8s.io/apimachinery/pkg/runtime"
)

// RegisterDefaults adds defaulters functions to the given scheme.
// Public to allow building arbitrary schemes.
// All generated defaulters are covering - they call all nested defaulters.
func RegisterDefaults(scheme *runtime.Scheme) error {
        scheme.AddTypeDefaultingFunc(&TestType{}, func(obj interface{}) { SetObjectDefaults_TestType(obj.(*TestType)) })
        scheme.AddTypeDefaultingFunc(&TestTypeList{}, func(obj interface{}) { SetObjectDefaults_TestTypeList(obj.(*TestTypeList)) })
        return nil
}

func SetObjectDefaults_TestType(in *TestType) {
        SetDefaults_TestType(in)
}

func SetObjectDefaults_TestTypeList(in *TestTypeList) {
        for i := range in.Items {
                a := &in.Items[i]
                SetObjectDefaults_TestType(a)
        }
}

```

### What did you expect to happen?

defaulter-gen  `zz_generated.defaults.go` Content error.

### How can we reproduce it (as minimally and precisely as possible)?

```bash
dongjiang@MacBook Pro:customapis $ pwd
/Users/dongjiang/Documents/go/src/github.com/dongjiang1989/customapis
dongjiang@MacBook Pro:customapis $ ./hack/update-codegen.sh 
/Users/dongjiang/Documents/go/pkg/mod/k8s.io/code-generator@v0.32.1
Generating deepcopy code for 1 targets
Generating defaulter code for 1 targets
Generating openapi code for 1 targets
Generating applyconfig code for 1 targets
Generating client code for 1 targets
Generating lister code for 1 targets
Generating informer code for 1 targets
```

### Anything else we need to know?

_No response_

### Kubernetes version

<details>

```console
$ kubectl version
# paste output here
```

</details>

code-generator v1.32.1 and  v1.32.0


### Cloud provider

<details>

</details>


### OS version

<details>

```console
# On Linux:
$ cat /etc/os-release
# paste output here
$ uname -a
# paste output here

# On Windows:
C:\> wmic os get Caption, Version, BuildNumber, OSArchitecture
# paste output here
```

</details>


### Install tools

<details>

</details>


### Container runtime (CRI) and version (if applicable)

<details>

</details>


### Related plugins (CNI, CSI, ...) and versions (if applicable)

<details>

</details>