DeploymentTemplate with empty parameters stays OutOfSync in Argo CD #13436

Bug information

Steps to reproduce

1. Install Radius and Argo CD on a cluster (seen on kind with Radius 0.61.1 and Argo CD 3.5.5, Helm chart 10.10.5).

2. Generate a DeploymentTemplate from a Bicep file that has no parameters:

   echo "// empty" > empty.bicep
   rad bicep generate-kubernetes-manifest empty.bicep --destination-file plain/fake-dt.yaml --group playground

   The generated file contains spec.parameters: {}.

3. Commit plain/fake-dt.yaml and point an Argo CD Application at plain, with automated sync.

4. Run argocd app get <app> --refresh and argocd app diff <app>.

Observed behavior

Radius deploys the template (kubectl get deploymenttemplates shows Ready), but Argo CD keeps the DeploymentTemplate OutOfSync. The only diff is:

===== radapp.io/DeploymentTemplate playground/empty.bicep ======
53a54
>   parameters: {}

Re-syncing doesn't help: Argo CD re-applies parameters: {}, and the controller removes it again.

Cause: the live object's metadata.generation is 2 because the controller rewrites the spec when it adds its finalizer:

• r.Client.Update in pkg/controller/reconciler/deploymenttemplate_reconciler.go (around line 326).
• Parameters is a map[string]string with the tag json:"parameters,omitempty" in pkg/controller/api/radapp.io/v1alpha3/deploymenttemplate_types.go (line 30).
• So the update serializes the empty map away.

Desired behavior

An applied DeploymentTemplate with no parameters shows Synced in Argo CD (and in any GitOps tool that compares desired and live state).

Possible fixes:

• The generator leaves out parameters when it's empty.
• The controller adds its finalizer with a patch instead of a full update.

Workaround

Either delete the parameters: {} line from the generated manifest, or add an ignoreDifferences entry for /spec/parameters to the Argo CD Application.

System information

rad Version

0.61.1

Operating system

macOS, Apple silicon (arm64); kind cluster

Additional context

Found while prototyping Argo CD support (design note in #13323).