I’m trying to deploy my application using Helm, but I encounter the following error when running a dry-run upgrade command:

     helm upgrade myapp --install --dry-run . -f ./values.yaml --namespace my-namespace --set releaseVersion=1.0.0
Release "myapp" does not exist. Installing it now.
Error: rendered manifests contain a resource that already exists. Unable to continue with install: ConfigMap "myapp-config" in namespace "my-namespace" exists and cannot be imported into the current release: invalid ownership metadata; annotation validation error: key "meta.helm.sh/release-name" must equal "myapp": current value is "old-release-name"

I have the following deployment.yaml file:

{{- if .Values.configMapName }}
        - name: {{ $app }}-config-volume
          configMap:
            name: {{ .Values.configMapName }}
            items:
              - key: config.json
                path: config.json
      {{- end }}
{{- if .Values.configMapName }}
          - name: {{ $app }}-config-volume
            mountPath: /opt/application/config.json
            subPath: config.json
            readOnly: true
        {{- end }}

And the configmap.yaml file:

apiVersion: v1
kind: ConfigMap
metadata:
  name: myapp-config
data:
  config.json: |
    {
      "key": "value"
    }

I have different values files for different environments. Initially, I deployed for one environment with a specific release name, and it went fine. Today, I tried to deploy for another environment with a different release name that didn’t have any configMapName in the values file.

During the Helm upgrade, it tries to install the release but fails because a ConfigMap with the same name already exists and has metadata indicating it belongs to a different release.

How can I resolve this error without manually deleting the existing ConfigMap every time?

Is there a way to make Helm ignore the existing ConfigMap and update it with the new release metadata?