Add ability to drop values from ArgParserResults

go/libraries/utils/argparser/args_test.go

@@ -280,3 +280,48 @@ func TestValidation(t *testing.T) {
 		t.Error("Arg list issues")
 	}
 }
+
+func TestDropValue(t *testing.T) {
+	ap := NewArgParserWithVariableArgs("test")
+
+	ap.SupportsString("string", "", "string_value", "A string")
+	ap.SupportsFlag("flag", "", "A flag")
+
+	apr, err := ap.Parse([]string{"--string", "str", "--flag", "1234"})
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+
+	newApr1 := apr.DropValue("string")
+	if apr.Equals(newApr1) {
+		t.Error("Original value and new value are equal")
+	}
+	_, hasVal := newApr1.GetValue("string")
+	if hasVal {
+		t.Error("DropValue failed to drop string")
+	}
+	_, hasVal = newApr1.GetValue("flag")
+	if !hasVal {
+		t.Error("DropValue dropped the wrong value")
+	}
+	if newApr1.NArg() != 1 || newApr1.Arg(0) != "1234" {
+		t.Error("DropValue didn't preserve args")
+	}
+
+	newApr2 := apr.DropValue("flag")
+	if apr.Equals(newApr2) {
+		t.Error("DropValue failed to drop flag")
+	}
+	_, hasVal = newApr2.GetValue("string")
+	if !hasVal {
+		t.Error("DropValue dropped the wrong value")
+	}
+	_, hasVal = newApr2.GetValue("flag")
+	if hasVal {
+		t.Error("DropValue failed to drop flag")
+	}
+	if newApr2.NArg() != 1 || newApr2.Arg(0) != "1234" {
+		t.Error("DropValue didn't preserve args")
+	}
+
+}

go/libraries/utils/argparser/results.go

@@ -121,6 +121,23 @@ func (res *ArgParseResults) GetValues(names ...string) map[string]string {
 	return vals
 }
 
+// DropValue removes the value for the given name from the results. A new ArgParseResults object is returned without the
+// names value. If the value is not present in the results then the original results object is returned.
+func (res *ArgParseResults) DropValue(name string) *ArgParseResults {
+	if _, ok := res.options[name]; !ok {
+		return res
+	}
+
+	newNamedArgs := make(map[string]string, len(res.options)-1)
+	for flag, val := range res.options {
+		if flag != name {
+			newNamedArgs[flag] = val
+		}
+	}
+
+	return &ArgParseResults{newNamedArgs, res.Args, res.parser}
+}
+
 func (res *ArgParseResults) MustGetValue(name string) string {
 	val, ok := res.options[name]