<p>I'd like to check that my kubernetes helm chart does not define unused values in <code>values.yaml</code>. This should include any subcharts such that if you've defined <code>subchart.foo.bar: ???</code> in the top-level <code>values.yaml</code> that key is definitely used in the subchart, or possibly as a short-cut mentioned in the <code>subchart/values.yaml</code>.</p>

<p>This is needed to prevent us from shipping bogus "documentation" in the <code>values.yaml</code>, for example if a key in a subchart has been changed or removed.</p>

<p>Ideally there would also be some possibility to report on which subchart values have not been overridden in the top-level chart, though this is less concerning.</p>

<p>Are there any existing tools that can help with this?</p>

<p>Since the Helm v3 release you can now define a schema for your <strong>values</strong>. On commands like <code>helm install</code> your provided values are automatically validated against the schema.</p>

<p>Please see the official documentation: <a href="https://helm.sh/docs/topics/charts/#schema-files" rel="nofollow noreferrer">https://helm.sh/docs/topics/charts/#schema-files</a></p>

<p>Schema validation works for subcharts too, this is also mentioned in the documentation on the link above.</p>
