Update ApplyDaemonSet to rely on a hash of the spec

This removes the need for the caller to be able to force a
rollout. Any state that is not present in the spec should instead be
added as an annotation so that a rollout will occur when the external
state changes.

This is an intentional breaking change to encourage switching to the
revised function. Callers who want to continue using the
previous (deprecated) implementation will need to change the name of
the function they are calling to ApplyDaemonSetWithForce.

pkg/operator/resource/resourceapply/apps.go

@@ -159,13 +159,49 @@ func ApplyDeploymentWithForce(client appsclientv1.DeploymentsGetter, recorder ev
 	return actual, true, err
 }
 
-// ApplyDaemonSet merges objectmeta and requires matching generation. It returns the final Object, whether any change as made, and an error
-func ApplyDaemonSet(client appsclientv1.DaemonSetsGetter, recorder events.Recorder, requiredOriginal *appsv1.DaemonSet, expectedGeneration int64, forceRollout bool) (*appsv1.DaemonSet, bool, error) {
+// ApplyDaemonSet ensures the form of the specified daemonset is present in the API. If it
+// does not exist, it will be created. If it does exist, the metadata of the required
+// daemonset will be merged with the existing daemonset and an update performed if the
+// daemonset spec and metadata differ from the previously required spec and metadata. For
+// further detail, check the top-level comment.
+//
+// NOTE: The previous implementation of this method was renamed to ApplyDaemonSetWithForce. If
+// are reading this in response to a compile error due to the change in signature, you have
+// the following options:
+//
+// - Update the calling code to rely on the spec comparison provided by the new
+// implementation. If the code in question was specifying the force parameter to ensure
+// rollout in response to changes in resources external to the daemonset, it will need to be
+// revised to set that external state as an annotation e.g.
+//
+//   myoperator.openshift.io/my-resource: <resourceVersion>
+//
+// - Update the call to use ApplyDaemonSetWithForce. This is available as a temporary measure
+// but the method is deprecated and will be removed in 4.6.
+func ApplyDaemonSet(client appsclientv1.DaemonSetsGetter, recorder events.Recorder,
+	requiredOriginal *appsv1.DaemonSet, expectedGeneration int64) (*appsv1.DaemonSet, bool, error) {
+
+	required := requiredOriginal.DeepCopy()
+	err := SetSpecHashAnnotation(&required.ObjectMeta, required.Spec)
+	if err != nil {
+		return nil, false, err
+	}
+
+	return ApplyDaemonSetWithForce(client, recorder, required, expectedGeneration, false)
+}
+
+// ApplyDaemonSetWithForce merges objectmeta and requires matching generation. It returns the final Object, whether any change as made, and an error
+// DEPRECATED - This method will be removed in 4.6 and callers will need to migrate to ApplyDaemonSet before then.
+func ApplyDaemonSetWithForce(client appsclientv1.DaemonSetsGetter, recorder events.Recorder, requiredOriginal *appsv1.DaemonSet, expectedGeneration int64, forceRollout bool) (*appsv1.DaemonSet, bool, error) {
 	required := requiredOriginal.DeepCopy()
 	if required.Annotations == nil {
 		required.Annotations = map[string]string{}
 	}
-	required.Annotations["operator.openshift.io/pull-spec"] = required.Spec.Template.Spec.Containers[0].Image
+	if _, ok := required.Annotations[specHashAnnotation]; !ok {
+		// If the spec hash annotation is not present, the caller expects the
+		// pull-spec annotation to be applied.
+		required.Annotations["operator.openshift.io/pull-spec"] = required.Spec.Template.Spec.Containers[0].Image
+	}
 	existing, err := client.DaemonSets(required.Namespace).Get(context.TODO(), required.Name, metav1.GetOptions{})
 	if apierrors.IsNotFound(err) {
 		actual, err := client.DaemonSets(required.Namespace).Create(context.TODO(), required, metav1.CreateOptions{})