Checklist

• I did not find a related open issue.
• I did not find a solution in the troubleshooting guide: (https://cloud.google.com/config-connector/docs/troubleshooting)
• If this issue is time-sensitive, I have submitted a corresponding issue with GCP support.

Bug Description

I found the following when trying to reference a PubSubSchema from a PubSubTopic:

• the 'schemaSettings.encoding' attribute is defined as optional, however the resource fails to deploy unless specified (API error)
• the 'schemaSettings.encoding' attribute is listed as having a default value of 'ENCODING_UNSPECIFIED', however the resource fails to deploy unless specified (API error)
• child attributes of 'schemaSettings' are immutable, but not documented as such.
• 'schemaSettings' cannot be added after a topic has been deployed

Additional Diagnostic Information

na

Kubernetes Cluster Version

v1.22.10-gke.600

Config Connector Version

1.90.0

Config Connector Mode

namespaced mode (default)

Log Output

schemaSettings.encoding not specified:
Update call failed: error applying desired state: summary: Error creating Topic: googleapi: Error 400: Schema settings for the topic projects/project/topics/pubsubtopic-example must include both the name and the encoding.

schemaSettings.encoding set to ENCODING_UNSPECIFIED:
Update call failed: error applying desired state: summary: Error creating Topic: googleapi: Error 400: Schema settings for the topic projects/project/topics/pubsubtopic-example must include both the name and the encoding.

updating any values under schemaSettings:
Update call failed: error applying desired state: summary: Error updating Topic "projects/project/topics/pubsubtopic-example0": googleapi: Error 400: Invalid update_mask provided in the UpdateTopicRequest: the 'schema_settings' field in the Topic is not mutable.

Steps to reproduce the issue

noted in description

YAML snippets

# encoding attribute not defined
---
apiVersion: pubsub.cnrm.cloud.google.com/v1beta1
kind: PubSubTopic
metadata:
  name: pubsubtopic-example
spec:
  schemaSettings:
    schemaRef:
      name: pubsubschema-sample
# encoding value set to ENCODING_UNSPECIFIED
---
apiVersion: pubsub.cnrm.cloud.google.com/v1beta1
kind: PubSubTopic
metadata:
  name: pubsubtopic-example
spec:
  schemaSettings:
    encoding: ENCODING_UNSPECIFIED
    schemaRef:
      name: pubsubschema-sample