Change switch to regex

pkg/chartutil/values.go

@@ -21,6 +21,7 @@ import (
 	"io"
 	"io/ioutil"
 	"log"
+	"regexp"
 	"strings"
 
 	"github.com/ghodss/yaml"
@@ -282,10 +283,12 @@ func coalesceValues(c *chart.Chart, v map[string]interface{}) (map[string]interf
 		// This allows Helm's various sources of values (value files or --set) to
 		// remove incompatible keys from any previous chart, file, or set values.
 		// ref: http://www.yaml.org/spec/1.2/spec.html#id2803362
-		switch val {
-		case "null", "Null", "NULL", "~":
-			delete(v, key)
-			continue
+		var nullPattern = regexp.MustCompile("^(?:null|Null|NULL|~)$")
+		if str, ok := val.(string); ok {
+			if nullPattern.MatchString(str) {
+				delete(v, key)
+				continue
+			}
 		}
 
 		if _, ok := v[key]; !ok {