(new): expand runtime APIs

(fix): harden concurrent lifecycle
(tests): add regression coverage
(doc): update v1.2 guidance

bot_opts_loader.go

@@ -97,6 +97,9 @@ func (codec BotOptsFileJSONCodec) FromBytes(data []byte) (*BotOpts, error) {
 
 // ToBytes encodes BotOpts into JSON file bytes.
 func (codec BotOptsFileJSONCodec) ToBytes(opts *BotOpts) ([]byte, error) {
+	if opts == nil {
+		return nil, ErrOptsIsNil
+	}
 	fileOpts := &BotOptsFileJSON{
 		Version:       ConfigVersion,
 		Token:         opts.Token,
@@ -143,7 +146,7 @@ func (codec BotOptsFileJSONCodec) EscapeEnv(s string) string {
 	return string(data[1 : len(data)-1])
 }
 
-var envParameterRegex = regexp.MustCompile(`\{\{\s*(\w+)\s*\}\}`)
+var envParameterRegex = regexp.MustCompile(`\{\{\s*(\w+)\s*}}`)
 
 type botOptsFileEnvEscaper interface {
 	EscapeEnv(string) string
@@ -159,6 +162,9 @@ type BotOptsFileCodec interface {
 
 // LoadBotOptsFile reads a config file, expands env placeholders, and decodes BotOpts.
 func LoadBotOptsFile(codec BotOptsFileCodec, filename string) (*BotOpts, error) {
+	if isNilValue(codec) {
+		return nil, ErrCodecIsNil
+	}
 	f, err := os.Open(filename)
 	if err != nil {
 		return nil, err
@@ -174,6 +180,12 @@ func LoadBotOptsFile(codec BotOptsFileCodec, filename string) (*BotOpts, error)
 
 // SaveBotOptsFile encodes BotOpts with codec and writes the result to filename.
 func SaveBotOptsFile(codec BotOptsFileCodec, filename string, opts *BotOpts) error {
+	if isNilValue(codec) {
+		return ErrCodecIsNil
+	}
+	if opts == nil {
+		return ErrOptsIsNil
+	}
 	data, err := codec.ToBytes(opts)
 	if err != nil {
 		return err