Helm Error converting YAML to JSON: yaml: line 20: did not find expected key - kubernetes

Question

I don't really know what is the error here, is a simple helm deploy with a _helpers.tpl, it doesn't make sense and is probably a stupid mistake, the code:
deploy.yaml
apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
{{ include "metadata.name" . }}-deploy
spec:
selector:
matchLabels:
app: nginx
replicas: 2 # tells deployment to run 2 pods matching the template
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.14.2
ports:
- containerPort: 80
vars: {{- include "envs.var" .Values.secret.data }}
_helpers.tpl
{{- define "envs.var"}}
{{- range $key := . }}
- name: {{ $key | upper | quote}}
valueFrom:
secretKeyRef:
key: {{ $key | lower }}
name: {{ $key }}-auth
{{- end }}
{{- end }}
values.yaml
secret:
data:
username: root
password: test
the error
Error: YAML parse error on mychart/templates/deploy.yaml: error converting YAML to JSON: yaml: line 21: did not find expected key

Answer 1

Here this problem happens because of indent. You can resolve by updating
env: {{- include "envs.var" .Values.secret.data | nindent 12 }}

Answer 2

Simplest way to resolve this kind of issues is to use tools.
These are mostly indentation issues, and can be resolved very easily using the right tool
npm install -g yaml-lint
yaml-lint is one such tool
PS E:\vsc-workspaces\grafana-1> yamllint .\grafana.yaml
× YAML Lint failed for C:/Users/mnadeem6/vsc-workspaces/grafana-1/grafana.yaml
× bad indentation of a mapping entry at line 137, column 11:
restartPolicy: Always
^
PS E:\vsc-workspaces\grafana-1> yamllint .\grafana.yaml
√ YAML Lint successful.