[BUG] vcsim: cloning a vm with the duplicated name should fail

[Syuparn]

Describe the bug

When the duplicated vm name is specified to CloneVM_Task request, it succeeds and the created vm has same path to the existng one.

To Reproduce
Steps to reproduce the behavior:

1. run vcsim without any options
2. run a script below

source code (click to open)

package main

import (
        "context"
        "fmt"
        "net/url"
        "path"

        "github.com/vmware/govmomi"
        "github.com/vmware/govmomi/find"
        "github.com/vmware/govmomi/vim25/types"
)

func main() {
        ctx := context.Background()
        u, _ := url.Parse("https://user:pass@127.0.0.1:8989/sdk")
        c, _ := govmomi.NewClient(ctx, u, true)

        finder := find.NewFinder(c.Client)
        vm, _ := finder.VirtualMachine(ctx, "DC0_H0_VM0")

        folder, _ := finder.Folder(ctx, path.Dir(vm.InventoryPath))

        config := types.VirtualMachineCloneSpec{
                Template: false,
                PowerOn:  true,
        }
        // name and folder are same as original's ones
        task, err := vm.Clone(ctx, folder, vm.Name(), config)
        if err != nil {
                fmt.Printf("failed to clone: %s", err)
                return
        }

        result, err := task.WaitForResult(ctx)
        if err != nil {
                fmt.Printf("task failed: %s", err)
                return
        }

        fmt.Printf("state: %#v\n", result.State)
}

Expected behavior

The task failed by a name duplication error.

$ go run .\main.go
task failed: The name 'DC0_H0_VM0' already exists.

Affected version

• vcsim v0.29.0

Screenshots/Debug Output

The task succeeds and two vms are located in the same path.

$ go run main.go
state: "success"

$ govc vm.info DC0_H0_VM0
Name:           DC0_H0_VM0
  Path:         /DC0/vm/DC0_H0_VM0
  UUID:         265104de-1472-547c-b873-6dc7883fb6cb
  Guest name:   otherGuest
  Memory:       32MB
  CPU:          1 vCPU(s)
  Power state:  poweredOn
  Boot time:    2022-11-03 20:34:07.225752728 +0900 JST
  IP address:
  Host:         DC0_H0
Name:           DC0_H0_VM0
  Path:         /DC0/vm/DC0_H0_VM0
  UUID:         0d844f57-2f52-591a-bcff-16c283cd5559
  Guest name:   otherGuest
  Memory:       32MB
  CPU:          1 vCPU(s)
  Power state:  poweredOff
  Boot time:    <nil>
  IP address:
  Host:         DC0_H0

Additional context

govc is not affected by this issue since it checks vmx file collision before CloneVM_Task.

$ govc vm.clone -host DC0_H0 -vm DC0_H0_VM0 DC0_H0_VM0
govc: file [LocalDS_0] DC0_H0_VM0/DC0_H0_VM0.vmx already exists