cmd: initialize config fields before use

cmd/yamlfmt/config.go

@@ -175,7 +175,7 @@ func validatePath(path string) error {
 }
 
 func makeCommandConfigFromData(configData map[string]any) (*command.Config, error) {
-	var config *command.Config
+	config := command.NewConfig()
 	err := mapstructure.Decode(configData, &config)
 	if err != nil {
 		return nil, err
@@ -222,7 +222,7 @@ func makeCommandConfigFromData(configData map[string]any) (*command.Config, erro
 	config.Exclude = append(config.Exclude, flagExclude...)
 	config.Extensions = append(config.Extensions, flagExtensions...)
 
-	return config, nil
+	return &config, nil
 }
 
 func parseFormatterConfigFlag(flagValues []string) (map[string]any, error) {

command/command.go

@@ -40,6 +40,11 @@ type FormatterConfig struct {
 	FormatterSettings map[string]any `mapstructure:",remain"`
 }
 
+// NewFormatterConfig returns an empty formatter config with all fields initialized.
+func NewFormatterConfig() FormatterConfig {
+	return FormatterConfig{FormatterSettings: make(map[string]any)}
+}
+
 type Config struct {
 	Extensions      []string               `mapstructure:"extensions"`
 	Include         []string               `mapstructure:"include"`
@@ -49,6 +54,12 @@ type Config struct {
 	FormatterConfig *FormatterConfig       `mapstructure:"formatter,omitempty"`
 }
 
+// NewConfig returns an empty config with all fields initialized.
+func NewConfig() Config {
+	formatterConfig := NewFormatterConfig()
+	return Config{FormatterConfig: &formatterConfig}
+}
+
 type Command struct {
 	Operation Operation
 	Registry  *yamlfmt.Registry