feat(config): add reflection-based configFields framework

cmd/config_fields.go

@@ -0,0 +1,55 @@
+package cmd
+
+import "reflect"
+
+// ConfigField represents a single leaf field in the Config struct,
+// mapped to its dotted TOML key path.
+type ConfigField struct {
+	Key       string        // dotted key, e.g. "git.auto_commit"
+	Value     any           // current value
+	Default   any           // value from defaultConfig()
+	IsDefault bool          // Value == Default
+	Field     reflect.Value // settable reflect.Value (from cfg pointer)
+	Kind      reflect.Kind  // field type kind
+}
+
+// configFields walks cfg and defaults in parallel, returning a ConfigField
+// for every leaf field. Keys are built from TOML struct tags.
+func configFields(cfg, defaults *Config) []ConfigField {
+	var fields []ConfigField
+	walk(reflect.ValueOf(cfg).Elem(), reflect.ValueOf(defaults).Elem(), "", &fields)
+	return fields
+}
+
+func walk(cv, dv reflect.Value, prefix string, out *[]ConfigField) {
+	ct := cv.Type()
+	for i := 0; i < ct.NumField(); i++ {
+		sf := ct.Field(i)
+		tag := sf.Tag.Get("toml")
+		if tag == "" || tag == "-" {
+			continue
+		}
+
+		key := tag
+		if prefix != "" {
+			key = prefix + "." + tag
+		}
+
+		cfv := cv.Field(i)
+		dfv := dv.Field(i)
+
+		if sf.Type.Kind() == reflect.Struct {
+			walk(cfv, dfv, key, out)
+			continue
+		}
+
+		*out = append(*out, ConfigField{
+			Key:       key,
+			Value:     cfv.Interface(),
+			Default:   dfv.Interface(),
+			IsDefault: reflect.DeepEqual(cfv.Interface(), dfv.Interface()),
+			Field:     cfv,
+			Kind:      sf.Type.Kind(),
+		})
+	}
+}

cmd/config_fields_test.go

@@ -0,0 +1,138 @@
+package cmd
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestConfigFieldsReturnsAllFields(t *testing.T) {
+	cfg := defaultConfig()
+	defaults := defaultConfig()
+	fields := configFields(&cfg, &defaults)
+
+	// Count expected leaf fields by walking the struct
+	expected := countLeafFields(reflect.TypeOf(Config{}))
+	if len(fields) != expected {
+		t.Errorf("configFields returned %d fields, want %d", len(fields), expected)
+	}
+}
+
+func countLeafFields(t reflect.Type) int {
+	n := 0
+	for i := 0; i < t.NumField(); i++ {
+		f := t.Field(i)
+		if f.Type.Kind() == reflect.Struct {
+			n += countLeafFields(f.Type)
+		} else {
+			n++
+		}
+	}
+	return n
+}
+
+func TestConfigFieldsDottedKeys(t *testing.T) {
+	cfg := defaultConfig()
+	defaults := defaultConfig()
+	fields := configFields(&cfg, &defaults)
+
+	want := map[string]bool{
+		"display_ascii_art":             true,
+		"key.always_prompt_delete":      true,
+		"key.always_prompt_glob_delete": true,
+		"key.always_prompt_overwrite":   true,
+		"store.default_store_name":      true,
+		"store.list_all_stores":         true,
+		"store.always_prompt_delete":    true,
+		"store.always_prompt_overwrite": true,
+		"git.auto_fetch":               true,
+		"git.auto_commit":              true,
+		"git.auto_push":                true,
+	}
+
+	got := make(map[string]bool)
+	for _, f := range fields {
+		got[f.Key] = true
+	}
+
+	for k := range want {
+		if !got[k] {
+			t.Errorf("missing key %q", k)
+		}
+	}
+	for k := range got {
+		if !want[k] {
+			t.Errorf("unexpected key %q", k)
+		}
+	}
+}
+
+func TestConfigFieldsAllDefaults(t *testing.T) {
+	cfg := defaultConfig()
+	defaults := defaultConfig()
+	fields := configFields(&cfg, &defaults)
+
+	for _, f := range fields {
+		if !f.IsDefault {
+			t.Errorf("field %q should be default, got Value=%v Default=%v", f.Key, f.Value, f.Default)
+		}
+	}
+}
+
+func TestConfigFieldsDetectsNonDefault(t *testing.T) {
+	cfg := defaultConfig()
+	cfg.Git.AutoCommit = true
+	defaults := defaultConfig()
+	fields := configFields(&cfg, &defaults)
+
+	for _, f := range fields {
+		if f.Key == "git.auto_commit" {
+			if f.IsDefault {
+				t.Errorf("git.auto_commit should not be default after change")
+			}
+			if f.Value != true {
+				t.Errorf("git.auto_commit Value = %v, want true", f.Value)
+			}
+			return
+		}
+	}
+	t.Error("git.auto_commit not found in fields")
+}
+
+func TestConfigFieldsSettable(t *testing.T) {
+	cfg := defaultConfig()
+	defaults := defaultConfig()
+	fields := configFields(&cfg, &defaults)
+
+	for _, f := range fields {
+		if f.Key == "git.auto_push" {
+			if f.Kind != reflect.Bool {
+				t.Errorf("git.auto_push Kind = %v, want Bool", f.Kind)
+			}
+			f.Field.SetBool(true)
+			if !cfg.Git.AutoPush {
+				t.Error("setting field via reflect did not update cfg")
+			}
+			return
+		}
+	}
+	t.Error("git.auto_push not found in fields")
+}
+
+func TestConfigFieldsStringField(t *testing.T) {
+	cfg := defaultConfig()
+	defaults := defaultConfig()
+	fields := configFields(&cfg, &defaults)
+
+	for _, f := range fields {
+		if f.Key == "store.default_store_name" {
+			if f.Kind != reflect.String {
+				t.Errorf("store.default_store_name Kind = %v, want String", f.Kind)
+			}
+			if f.Value != "default" {
+				t.Errorf("store.default_store_name Value = %v, want 'default'", f.Value)
+			}
+			return
+		}
+	}
+	t.Error("store.default_store_name not found in fields")
+}