Always copying passed options to protect callback data integrity.

options.go

@@ -46,6 +46,15 @@ type SendOptions struct {
 	ParseMode ParseMode
 }
 
+func (og *SendOptions) copy() *SendOptions {
+	cp := *og
+	if cp.ReplyMarkup != nil {
+		cp.ReplyMarkup = cp.ReplyMarkup.copy()
+	}
+
+	return &cp
+}
+
 // ReplyMarkup controls two convenient options for bot-user communications
 // such as reply keyboard and inline "keyboard" (a grid of buttons as a part
 // of the message).
@@ -87,6 +96,28 @@ type ReplyMarkup struct {
 	Selective bool `json:"selective,omitempty"`
 }
 
+func (og *ReplyMarkup) copy() *ReplyMarkup {
+	cp := *og
+
+	cp.ReplyKeyboard = make([][]ReplyButton, len(og.ReplyKeyboard))
+	for i, row := range og.ReplyKeyboard {
+		cp.ReplyKeyboard[i] = make([]ReplyButton, len(row))
+		for j, btn := range row {
+			cp.ReplyKeyboard[i][j] = btn
+		}
+	}
+
+	cp.InlineKeyboard = make([][]InlineButton, len(og.InlineKeyboard))
+	for i, row := range og.InlineKeyboard {
+		cp.InlineKeyboard[i] = make([]InlineButton, len(row))
+		for j, btn := range row {
+			cp.InlineKeyboard[i][j] = btn
+		}
+	}
+
+	return &cp
+}
+
 // ReplyButton represents a button displayed in reply-keyboard.
 //
 // Set either Contact or Location to true in order to request

util.go

@@ -96,13 +96,13 @@ func extractOptions(how []interface{}) *SendOptions {
 	for _, prop := range how {
 		switch opt := prop.(type) {
 		case *SendOptions:
-			opts = opt
+			opts = opt.copy()
 
 		case *ReplyMarkup:
 			if opts == nil {
 				opts = &SendOptions{}
 			}
-			opts.ReplyMarkup = opt
+			opts.ReplyMarkup = opt.copy()
 
 		case Option:
 			if opts == nil {