feat: support json:"-" in mapping (#3521)

core/mapping/unmarshaler.go

@@ -20,6 +20,7 @@ import (
 const (
 	defaultKeyName = "key"
 	delimiter      = '.'
+	ignoreKey      = "-"
 )
 
 var (
@@ -437,6 +438,10 @@ func (u *Unmarshaler) processAnonymousField(field reflect.StructField, value ref
 		return err
 	}
 
+	if key == ignoreKey {
+		return nil
+	}
+
 	if options.optional() {
 		return u.processAnonymousFieldOptional(field, value, key, m, fullName)
 	}
@@ -724,6 +729,10 @@ func (u *Unmarshaler) processNamedField(field reflect.StructField, value reflect
 		return err
 	}
 
+	if key == ignoreKey {
+		return nil
+	}
+
 	fullName = join(fullName, key)
 	if opts != nil && len(opts.EnvVar) > 0 {
 		envVal := proc.Env(opts.EnvVar)