Preserve Audita module selections in YAML output

internal/config/credential_projection.go

@@ -24,20 +24,25 @@ func (cfg StorageS3Config) MarshalYAML() (any, error) {
 // MarshalYAML exposes only public Audita credential reference names.
 func (cfg AuditaConfig) MarshalYAML() (any, error) {
 	type safeAudita struct {
-		Binary                string   `yaml:"binary"`
-		Timeout               string   `yaml:"timeout"`
-		Credentials           []string `yaml:"credentials,omitempty"`
-		Modules               []string `yaml:"modules"`
-		Overlay               string   `yaml:"overlay"`
-		ProposalProfile       string   `yaml:"proposal_profile"`
-		ValidationProfile     string   `yaml:"validation_profile"`
-		TranscriptDescription string   `yaml:"transcript_description"`
-		ConfigPath            string   `yaml:"config_path"`
-		OutputSchema          string   `yaml:"output_schema"`
+		Binary                string    `yaml:"binary"`
+		Timeout               string    `yaml:"timeout"`
+		Credentials           []string  `yaml:"credentials,omitempty"`
+		Modules               *[]string `yaml:"modules,omitempty"`
+		Overlay               string    `yaml:"overlay"`
+		ProposalProfile       string    `yaml:"proposal_profile"`
+		ValidationProfile     string    `yaml:"validation_profile"`
+		TranscriptDescription string    `yaml:"transcript_description"`
+		ConfigPath            string    `yaml:"config_path"`
+		OutputSchema          string    `yaml:"output_schema"`
+	}
+	// A nil pointer omits the override; a pointer to an empty slice disables modules.
+	var modules *[]string
+	if cfg.Modules != nil {
+		modules = &cfg.Modules
 	}
 	return safeAudita{
 		Binary: cfg.Binary, Timeout: cfg.Timeout, Credentials: secretReferenceNames(cfg.Credentials),
-		Modules: cfg.Modules, Overlay: cfg.Overlay, ProposalProfile: cfg.ProposalProfile,
+		Modules: modules, Overlay: cfg.Overlay, ProposalProfile: cfg.ProposalProfile,
 		ValidationProfile: cfg.ValidationProfile, TranscriptDescription: cfg.TranscriptDescription,
 		ConfigPath: cfg.ConfigPath, OutputSchema: cfg.OutputSchema,
 	}, nil

internal/config/credential_projection_test.go

@@ -0,0 +1,33 @@
+package config
+
+import (
+	"reflect"
+	"testing"
+
+	"gopkg.in/yaml.v3"
+)
+
+func TestAuditaYAMLPreservesModuleSelection(t *testing.T) {
+	for _, tc := range []struct {
+		name    string
+		modules []string
+	}{
+		{name: "omitted"},
+		{name: "explicit empty", modules: []string{}},
+		{name: "ordered repetitions", modules: []string{"grammar", "names", "grammar"}},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			data, err := yaml.Marshal(AuditaConfig{Modules: tc.modules})
+			if err != nil {
+				t.Fatal(err)
+			}
+			var decoded AuditaConfig
+			if err := yaml.Unmarshal(data, &decoded); err != nil {
+				t.Fatal(err)
+			}
+			if !reflect.DeepEqual(decoded.Modules, tc.modules) {
+				t.Fatalf("modules = %#v, want %#v; YAML:\n%s", decoded.Modules, tc.modules, data)
+			}
+		})
+	}
+}