SinkBinding eliminates all volumes on Deployment subject

[christophd]

Describe the bug Given the subject in a SinkBinding is an arbitrary Deployment that brings its own volumes/volumeMounts spec these get eliminated as soon as the SinkBinding has injected K_SINK envVars. As a result the initial volume/volumeMount information is lost on the Deployment.

Expected behavior The SinkBinding should preserve existing volume/volumeMount specs on the Deployment subject.

To Reproduce

• Create a Deployment with a custom volume/volumeMount
• Create a SinkBinding resource with the given Deployment as a subject
• See the existing volume/volumeMount disappear from the Deployment spec as soon as the SinkBinding envVar injection is done

Knative release version v1.14.0

Additional context used kubectl apply -f to create both Deployement and SinkBinding. Tested on local Kind cluster.

[Cali0707]

Probably related to some logic in https://github.com/knative/eventing/blob/6aa49dc1db88c5703a7d981d247dc3bb183c0b59/pkg/apis/sources/v1/sinkbinding_lifecycle.go#L142

/triage accepted

[Cali0707]

@christophd was oidc enabled when you found this?

[christophd]

no it was not

[Cali0707]

@christophd are you able to reproduce this issue on newer releases of knative? I just tried following your steps above with the yaml below and was unfortunately not able to reproduce...

apiVersion: v1
kind: ConfigMap
metadata:
  name: example-config
  namespace: default
data:
  key: value
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  namespace: default
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      volumes:
      - name: sample-volume
        configMap:
          name: example-config
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80
        volumeMounts:
        - name: sample-volume
          mountPath: /sample-volume
---
apiVersion: sources.knative.dev/v1
kind: SinkBinding
metadata:
  name: example-sb
  namespace: default
spec:
  subject:
    apiVersion: apps/v1
    kind: Deployment
    name: nginx-deployment
  sink:
    uri: "https://example.com"