desktop, android: fix parser for reactions (#5629)

* desktop, android: fix parser for reactions

* core: restrict API to known reactions

apps/ios/SimpleXChat/ChatTypes.swift

@@ -3391,8 +3391,12 @@ extension MsgReaction: Decodable {
             let type = try container.decode(String.self, forKey: CodingKeys.type)
             switch type {
             case "emoji":
-                let emoji = try container.decode(MREmojiChar.self, forKey: CodingKeys.emoji)
-                self = .emoji(emoji: emoji)
+                do {
+                    let emoji = try container.decode(MREmojiChar.self, forKey: CodingKeys.emoji)
+                    self = .emoji(emoji: emoji)
+                } catch {
+                    self = .unknown(type: "emoji")
+                }
             default:
                 self = .unknown(type: type)
             }

apps/multiplatform/common/src/commonMain/kotlin/chat/simplex/common/model/ChatModel.kt

@@ -2981,7 +2981,7 @@ sealed class MsgReaction {
       MREmojiChar.Heart -> "❤️"
       else -> emoji.value
     }
-    is Unknown -> ""
+    is Unknown -> "?"
   }
 
   companion object {
@@ -3003,8 +3003,13 @@ object MsgReactionSerializer : KSerializer<MsgReaction> {
     return if (json is JsonObject && "type" in json) {
       when(val t = json["type"]?.jsonPrimitive?.content ?: "") {
         "emoji" -> {
-          val emoji = Json.decodeFromString<MREmojiChar>(json["emoji"].toString())
-          if (emoji == null) MsgReaction.Unknown(t, json) else MsgReaction.Emoji(emoji)
+          val msgReaction = try {
+            val emoji = Json.decodeFromString<MREmojiChar>(json["emoji"].toString())
+            MsgReaction.Emoji(emoji)
+          } catch (e: Throwable) {
+            MsgReaction.Unknown(t, json)
+          }
+          msgReaction
         }
         else -> MsgReaction.Unknown(t, json)
       }

src/Simplex/Chat.hs

@@ -8463,8 +8463,8 @@ chatCommandP =
       "/_update item " *> (APIUpdateChatItem <$> chatRefP <* A.space <*> A.decimal <*> liveMessageP <* A.space <*> msgContentP),
       "/_delete item " *> (APIDeleteChatItem <$> chatRefP <*> _strP <*> _strP),
       "/_delete member item #" *> (APIDeleteMemberChatItem <$> A.decimal <*> _strP),
-      "/_reaction " *> (APIChatItemReaction <$> chatRefP <* A.space <*> A.decimal <* A.space <*> onOffP <* A.space <*> jsonP),
-      "/_reaction members " *> (APIGetReactionMembers <$> A.decimal <* " #" <*> A.decimal <* A.space <*> A.decimal <* A.space <*> jsonP),
+      "/_reaction " *> (APIChatItemReaction <$> chatRefP <* A.space <*> A.decimal <* A.space <*> onOffP <* A.space <*> (knownReaction <$?> jsonP)),
+      "/_reaction members " *> (APIGetReactionMembers <$> A.decimal <* " #" <*> A.decimal <* A.space <*> A.decimal <* A.space <*> (knownReaction <$?> jsonP)),
       "/_forward plan " *> (APIPlanForwardChatItems <$> chatRefP <*> _strP),
       "/_forward " *> (APIForwardChatItems <$> chatRefP <* A.space <*> chatRefP <*> _strP <*> sendMessageTTLP),
       "/_read user " *> (APIUserRead <$> A.decimal),

src/Simplex/Chat/Protocol.hs

@@ -407,6 +407,13 @@ data MsgReaction = MREmoji {emoji :: MREmojiChar} | MRUnknown {tag :: Text, json
 emojiTag :: IsString a => a
 emojiTag = "emoji"
 
+knownReaction :: MsgReaction -> Either String MsgReaction
+knownReaction = \case
+  r@MREmoji {} -> Right r
+  MRUnknown {} -> Left "unknown MsgReaction"
+
+-- parseJSON for MsgReaction parses unknown emoji reactions as MRUnknown with type "emoji",
+-- allowing to add new emojis in a backwards compatible way - UI shows them as ?
 instance FromJSON MsgReaction where
   parseJSON (J.Object v) = do
     tag <- v .: "type"