Bug: Operator does not differentiate between value 0 and missing field

[Kajot-dev]

The problem

When a certain property is wrapped in a condition and has a value of 0, condition evaulating to false in a template (property is no longer in the template), property does not get removed from the object.

Reproduction steps

Consider a following scenario: Using a NamespaceConfig you create a ResourceQuota in a project with some quota (for example persistentvolumeclaims) set with value 0.

For example:

apiVersion: v1
kind: ResourceQuota
metadata:
   name: some-quota
   namespace: my-namespace
spec:
  hard:
    persistentvolumeclaims: '0'
    otherquota: '5'

You want to use it based on a condition so you write something like this:

{{- if ne (index .Annotations "allow-pvc") "true" }}
persistentvolumeclaims: '0'
{{- end }}

Then if I set the annotation so the mentioned condition returned false I see:

Actual result:

apiVersion: v1
kind: ResourceQuota
metadata:
   name: some-quota
   namespace: my-namespace
spec:
  hard:
    persistentvolumeclaims: '0'
    otherquota: '5'

Expected result:

apiVersion: v1
kind: ResourceQuota
metadata:
   name: some-quota
   namespace: my-namespace
spec:
  hard:
    otherquota: '5'

Expected result can be achieved by removing the ResourceQuota object so it gets re-created by the operator. Operator does not see the difference between two mentioned resources (actual vs expected).