Add exported function to remove rules (#316)

* feat(rules): Add way to remove rule

* feat(rules): Remove unnecessary change

* feat(rules): Fix linting error

* feat(rules): Fix linting error

validator/validator.go

@@ -23,6 +23,17 @@ func AddRule(name string, ruleFunc RuleFunc) {
 	specifiedRules = append(specifiedRules, Rule{Name: name, RuleFunc: ruleFunc})
 }
 
+func RemoveRule(name string) {
+	var result []Rule // nolint:prealloc // using initialized with len(rules) produces a race condition
+	for _, r := range specifiedRules {
+		if r.Name == name {
+			continue
+		}
+		result = append(result, r)
+	}
+	specifiedRules = result
+}
+
 func Validate(schema *Schema, doc *QueryDocument, rules ...Rule) gqlerror.List {
 	if rules == nil {
 		rules = specifiedRules

validator/validator_test.go

@@ -178,3 +178,13 @@ func TestCustomRuleSet(t *testing.T) {
 	require.Equal(t, "some error message", errList[0].Message)
 	require.Equal(t, "some other error message", errList[1].Message)
 }
+
+func TestRemoveRule(t *testing.T) {
+	// no error
+	validator.RemoveRule("rule that does not exist")
+
+	validator.AddRule("Rule that should no longer exist", func(observers *validator.Events, addError validator.AddErrFunc) {})
+
+	// no error
+	validator.RemoveRule("Rule that should no longer exist")
+}