This is more complicated than it seems.

The following will return true in a template.

kindIs "int" 123

See https://go.dev/play/p/kUCfwEQzeoh for an example that shows exactly this.

The problem in the original issue is that 123 in the values.yaml file is parsed by the k8s yaml parser. The spec has data types for both integers and floating point numbers. But, the Kubernetes YAML parser turns any number into a float64. The following is a comment from that package:

// - This decodes any number (although it is an integer) into a float64 if the type of obj is unknown, e.g. *map[string]interface{}, *interface{}, or *[]interface{}. This means integers above +/- 2^53 will lose precision when round-tripping. Make a JSONOpt that calls d.UseNumber() to avoid this.

If you use an integer right in the template it will return true. If you use a number passed from the values.yaml file it will need to be a float64.

Related helm/helm#4982