⬆️ Update dependencies

vendor/github.com/alecthomas/kong/interpolate.go

@@ -5,7 +5,18 @@ import (
 	"regexp"
 )
 
-var interpolationRegex = regexp.MustCompile(`((?:\${([[:alpha:]_][[:word:]]*))(?:=([^}]+))?})|(\$)|([^$]+)`)
+var interpolationRegex = regexp.MustCompile(`(\$\$)|((?:\${([[:alpha:]_][[:word:]]*))(?:=([^}]+))?})|(\$)|([^$]+)`)
+
+// HasInterpolatedVar returns true if the variable "v" is interpolated in "s".
+func HasInterpolatedVar(s string, v string) bool {
+	matches := interpolationRegex.FindAllStringSubmatch(s, -1)
+	for _, match := range matches {
+		if name := match[3]; name == v {
+			return true
+		}
+	}
+	return false
+}
 
 // Interpolate variables from vars into s for substrings in the form ${var} or ${var=default}.
 func interpolate(s string, vars Vars, updatedVars map[string]string) (string, error) {
@@ -21,14 +32,16 @@ func interpolate(s string, vars Vars, updatedVars map[string]string) (string, er
 		}
 	}
 	for _, match := range matches {
-		if name := match[2]; name != "" {
+		if dollar := match[1]; dollar != "" {
+			out += "$"
+		} else if name := match[3]; name != "" {
 			value, ok := vars[name]
 			if !ok {
 				// No default value.
-				if match[3] == "" {
+				if match[4] == "" {
 					return "", fmt.Errorf("undefined variable ${%s}", name)
 				}
-				value = match[3]
+				value = match[4]
 			}
 			out += value
 		} else {