Description of problem:

Customer would like to define exceptions for placements outside of policyDefaults, but it doesn't work as documented.

https://github.com/open-cluster-management-io/policy-generator-plugin/blob/0b07cc7f2d4b64d6ff55562a874e8d2ef4bed905/docs/policygenerator-reference.yaml#L313 describes that you can use the same fields as in the PolicyDefaults, it seems but that's not true, I get an error message from the generator in ArgoCD.

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:

1. has been already investigated
3. ...

Actual results:

Here's the error:
policy projectrequest-template must specify only one of placement selector, placement path, or placement name

Looks like we don't allow overriding one type of Placement for another. The policyDefaults Placement object isn't being overridden by the policies Placement object--it seems it's just piling them together and generating the error.

For example:

apiVersion: policy.open-cluster-management.io/v1
kind: PolicyGenerator
policyDefaults: 
 placement: 
   clusterSelectors: 
     vendor: "OpenShift"
policies: 
 - name: my-policy
   manifests: 
     - path: my-policy.yaml
   placement: 
     placementPath: 
       ../my-placement.yaml

Expected results:

Additional info: