dev: rewrite linters Manager (#4419)

pkg/config/severity.go

@@ -1,5 +1,10 @@
 package config
 
+import (
+	"errors"
+	"fmt"
+)
+
 const severityRuleMinConditionsCount = 1
 
 type Severity struct {
@@ -8,6 +13,20 @@ type Severity struct {
 	Rules         []SeverityRule `mapstructure:"rules"`
 }
 
+func (s *Severity) Validate() error {
+	if len(s.Rules) > 0 && s.Default == "" {
+		return errors.New("can't set severity rule option: no default severity defined")
+	}
+
+	for i, rule := range s.Rules {
+		if err := rule.Validate(); err != nil {
+			return fmt.Errorf("error in severity rule #%d: %w", i, err)
+		}
+	}
+
+	return nil
+}
+
 type SeverityRule struct {
 	BaseRule `mapstructure:",squash"`
 	Severity string