优化结构

internal/config/runtime_test.go

@@ -168,3 +168,12 @@ func TestMergeRuntimeConfigPreservesOmittedSections(t *testing.T) {
 		t.Fatal("MergeRuntimeConfig leaked mutable storage state into current config")
 	}
 }
+
+func TestMergeRuntimeConfigPreservesOmittedNestedDataSections(t *testing.T) {
+	current := &Config{Data: &Data{Database: &Database{Source: "current-dsn"}}}
+	next := &Config{Data: &Data{}}
+	merged := MergeRuntimeConfig(current, next)
+	if merged.Data == nil || merged.Data.Database == nil || merged.Data.Database.Source != "current-dsn" {
+		t.Fatalf("nested database section was not preserved: %#v", merged.Data)
+	}
+}