feat(doctor): detects undecoded config keys

cmd/config.go

@@ -63,7 +63,8 @@ type GitConfig struct {
 }
 
 var (
-	config   Config
+	config              Config
+	configUndecodedKeys []string
 	asciiArt string = `                 ▄▄           
                  ██           
  ██▄███▄    ▄███▄██   ▄█████▄
@@ -77,7 +78,7 @@ var (
 )
 
 func init() {
-	config, configErr = loadConfig()
+	config, configUndecodedKeys, configErr = loadConfig()
 }
 
 func defaultConfig() Config {
@@ -105,24 +106,29 @@ func defaultConfig() Config {
 	}
 }
 
-func loadConfig() (Config, error) {
+func loadConfig() (Config, []string, error) {
 	cfg := defaultConfig()
 
 	path, err := configPath()
 	if err != nil {
-		return cfg, err
+		return cfg, nil, err
 	}
 
 	if _, err := os.Stat(path); err != nil {
 		if os.IsNotExist(err) {
-			return cfg, nil
+			return cfg, nil, nil
 		}
-		return cfg, err
+		return cfg, nil, err
 	}
 
-	_, err = toml.DecodeFile(path, &cfg)
+	meta, err := toml.DecodeFile(path, &cfg)
 	if err != nil {
-		return cfg, fmt.Errorf("parse %s: %w", path, err)
+		return cfg, nil, fmt.Errorf("parse %s: %w", path, err)
+	}
+
+	var undecoded []string
+	for _, key := range meta.Undecoded() {
+		undecoded = append(undecoded, key.String())
 	}
 
 	if cfg.Store.DefaultStoreName == "" {
@@ -133,10 +139,10 @@ func loadConfig() (Config, error) {
 		cfg.List.DefaultListFormat = defaultConfig().List.DefaultListFormat
 	}
 	if err := validListFormat(cfg.List.DefaultListFormat); err != nil {
-		return cfg, fmt.Errorf("parse %s: list.default_list_format: %w", path, err)
+		return cfg, undecoded, fmt.Errorf("parse %s: list.default_list_format: %w", path, err)
 	}
 
-	return cfg, nil
+	return cfg, undecoded, nil
 }
 
 func configPath() (string, error) {

cmd/doctor.go

@@ -161,6 +161,12 @@ func runDoctor(w io.Writer) bool {
 		}
 	}
 
+	// 7b. Unrecognised config keys
+	if len(configUndecodedKeys) > 0 {
+		emit("WARN", fmt.Sprintf("Unrecognised config key(s) (ignored):"))
+		tree(configUndecodedKeys)
+	}
+
 	// 8. Data directory
 	store := &Store{}
 	dataDir, err := store.path()

cmd/doctor_test.go

@@ -88,6 +88,36 @@ func TestDoctorIdentityPermissions(t *testing.T) {
 	}
 }
 
+func TestDoctorUndecodedKeys(t *testing.T) {
+	dataDir := t.TempDir()
+	configDir := t.TempDir()
+	t.Setenv("PDA_DATA", dataDir)
+	t.Setenv("PDA_CONFIG", configDir)
+
+	// Write a config with an unknown key.
+	cfgContent := "[store]\nno_such_key = true\n"
+	if err := os.WriteFile(filepath.Join(configDir, "config.toml"), []byte(cfgContent), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	savedCfg, savedUndecoded, savedErr := config, configUndecodedKeys, configErr
+	config, configUndecodedKeys, configErr = loadConfig()
+	t.Cleanup(func() {
+		config, configUndecodedKeys, configErr = savedCfg, savedUndecoded, savedErr
+	})
+
+	var buf bytes.Buffer
+	runDoctor(&buf)
+	out := buf.String()
+
+	if !strings.Contains(out, "Unrecognised config key") {
+		t.Errorf("expected undecoded key warning, got:\n%s", out)
+	}
+	if !strings.Contains(out, "store.no_such_key") {
+		t.Errorf("expected 'store.no_such_key' in output, got:\n%s", out)
+	}
+}
+
 func TestDoctorGitInitialised(t *testing.T) {
 	dataDir := t.TempDir()
 	configDir := t.TempDir()