Validate the kubebuilder edit command for the project layout

[prafull01]

Scenario1: When I am trying to run edit command without any inputs with no api created, throws following error

prafull@EMPID18004:~/go/src/github.com/prafull01/kubebuilder/proj$ ../bin/kubebuilder edit
Error: failed to edit project with version "3-alpha": can't find "COPY apis/ apis/"
Usage:
  kubebuilder edit [flags]

Examples:
# Enable the multigroup layout
        kubebuilder edit --multigroup

        # Disable the multigroup layout
        kubebuilder edit --multigroup=false
	

Flags:
  -h, --help         help for edit
      --multigroup   enable or disable multigroup layout

2020/10/28 11:07:49 failed to edit project with version "3-alpha": can't find "COPY apis/ apis/"

Scenario2: The same command I ran after creating one api and moving the scaffolding to multi group. The kb edit command without any inputs moved the project scaffolding to single group.

prafull@EMPID18004:~/go/src/github.com/prafull01/kubebuilder/proj$ ./bin/kubebuilder create api --group praf --kind Lakers --version v1
Create Resource [y/n]
y
Create Controller [y/n]
y
Writing scaffold for you to edit...
api/v1/lakers_types.go
controllers/lakers_controller.go
Running make:
$ make
/home/prafull/go/bin/controller-gen object:headerFile="hack/boilerplate.go.txt" paths="./..."
go fmt ./...
go vet ./...
go build -o bin/manager main.go
prafull@EMPID18004:~/go/src/github.com/prafull01/kubebuilder/proj$ ../bin/kubebuilder edit --multigroup=true

prafull@EMPID18004:~/go/src/github.com/prafull01/kubebuilder/proj$ cat PROJECT 
domain: my.domain
layout: go.kubebuilder.io/v3-alpha
multigroup: true
projectName: proj
repo: sigs.k8s.io/kubebuilder
resources:
- group: praf
  kind: Lakers
  version: v1
version: 3-alpha

prafull@EMPID18004:~/go/src/github.com/prafull01/kubebuilder/proj$ ../bin/kubebuilder edit 

prafull@EMPID18004:~/go/src/github.com/prafull01/kubebuilder/proj$ cat PROJECT 
domain: my.domain
layout: go.kubebuilder.io/v3-alpha
projectName: proj
repo: sigs.k8s.io/kubebuilder
resources:
- group: praf
  kind: Lakers
  version: v1
version: 3-alpha

Add a validation if the project is already on the same scaffolding and if yes, then don't try to edit it.

[prafull01]

/assign

[prafull01]

This happens because kb edit command sets the default value as false. However when editing the scaffolding already on same type, throws error. However this error should be catch in the validation itself and proper message should be shown to user

[prafull01]

The current implementation also fails if we try to edit a project which is already on the same type. Current, failure happens in the PostScaffolding of the kb edit command.

prafull@EMPID18004:~/go/src/github.com/prafull01/kubebuilder/proj$ ../bin/kubebuilder edit --multigroup=true
prafull@EMPID18004:~/go/src/github.com/prafull01/kubebuilder/proj$ ../bin/kubebuilder edit --multigroup=true
Error: failed to edit project with version "3-alpha": can't find "COPY api/ api/"
Usage:
  kubebuilder edit [flags]

Examples:
# Enable the multigroup layout
        kubebuilder edit --multigroup

        # Disable the multigroup layout
        kubebuilder edit --multigroup=false
	

Flags:
  -h, --help         help for edit
      --multigroup   enable or disable multigroup layout

2020/10/30 00:13:52 failed to edit project with version "3-alpha": can't find "COPY api/ api/"

This change will give more clear message to the user that he is already on the same type of the project layout.

/kind bug