OpenTelemetry Collector instance is not showing properly the version after upgrade

[iblancasa]

Depending on the source version you upgrade the OpenTelemetry Operator, the OpenTelemetry Collector will upgrade its version properly or not.

Steps to reproduce

1. Deploy OpenTelemetry Operator 0.63.1:

   $ kubectl create -f https://github.com/open-telemetry/opentelemetry-operator/releases/download/v0.63.1/opentelemetry-operator.yaml

2. Deploy one OpenTelemetry Collector instance
3. Upgrade the OpenTelemetry Operator version:

   $ kubectl apply -f https://github.com/open-telemetry/opentelemetry-operator/releases/download/v0.78.0/opentelemetry-operator.yaml

4. Wait until the upgrade process is triggered in the operator
5. Check the OTEL Collector version:

$ kubectl get otelcol
NAME       MODE         VERSION   AGE
simplest   deployment   0.63.1    20m

# Check if the image was updated
$ kubectl get deployment simplest-collector -o yaml
...
    spec:
      containers:
      - args:
        - --config=/conf/collector.yaml
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              apiVersion: v1
              fieldPath: metadata.name
        image: ghcr.io/open-telemetry/opentelemetry-collector-releases/opentelemetry-collector:0.78.0
...

As we can see, the image version was updated but not the OTEL Collector version.

Source of the problem

The error appears because this source code (pkg/collector/upgrade/upgrade.go):

	if instanceV.GreaterThan(&Latest.Version) {
		u.Log.Info("skipping upgrade for OpenTelemetry Collector instance, as it's newer than our latest version", "name", otelcol.Name, "namespace", otelcol.Namespace, "version", otelcol.Status.Version, "latest", Latest.Version.String())
		return otelcol, nil
	}

is before this one:

	otelcol.Status.Version = u.Version.OpenTelemetryCollector