Handle message_reaction updates to fix NRE (#93)

* Handle message_reaction updates to fix NRE

When receiving message_reaction updates from Telegram, both Message and EditedMessage are null, causing NRE when accessing EditedOrMessage.Photo.

- Add onMessageReaction function that logs reaction details as a span
- Update onUpdate to check for MessageReaction before processing OCR/message
- Add Tg.quickReaction test helper
- Add test to verify bot returns 200 OK on reaction updates

* crlf

* fix

Author: Szer

.editorconfig

@@ -0,0 +1,3 @@
+[*]
+end_of_line = lf
+insert_final_newline = true

.gitattributes

@@ -0,0 +1,17 @@
+* text=auto eol=lf
+
+*.bat  text eol=crlf
+*.cmd  text eol=crlf
+*.ps1  text eol=crlf
+*.psm1 text eol=crlf
+*.psd1 text eol=crlf
+
+*.sln  text eol=crlf
+
+*.png  binary
+*.jpg  binary
+*.jpeg binary
+*.gif  binary
+*.webp binary
+*.zip  binary
+*.pdf  binary

src/VahterBanBot.Tests/MessageTests.fs

@@ -59,5 +59,21 @@ type MessageTests(fixture: MlDisabledVahterTestContainers) =
 
         Assert.Null(dbMsg.Value.text)
     }
+
+    [<Fact>]
+    let ``Message reaction update returns OK`` () = task {
+        // first send a message to have a valid message_id
+        let msgUpdate = Tg.quickMsg(chat = fixture.ChatsToMonitor[0])
+        let! _ = fixture.SendMessage msgUpdate
+
+        // send a reaction update for that message
+        let reactionUpdate = Tg.quickReaction(
+            chat = fixture.ChatsToMonitor[0],
+            messageId = msgUpdate.Message.MessageId,
+            from = Tg.user()
+        )
+        let! resp = fixture.SendMessage reactionUpdate
+        Assert.Equal(HttpStatusCode.OK, resp.StatusCode)
+    }
 
     interface IAssemblyFixture<MlDisabledVahterTestContainers>

src/VahterBanBot.Tests/TgMessageUtils.fs

@@ -82,6 +82,20 @@ type Tg() =
                 )
             )
 
+    static member quickReaction(chat: Chat, messageId: int, from: User, ?emoji: string) =
+        let reactionEmoji = emoji |> Option.defaultValue "👍"
+        Update(
+            Id = next(),
+            MessageReaction = MessageReactionUpdated(
+                Chat = chat,
+                MessageId = messageId,
+                User = from,
+                Date = DateTime.UtcNow,
+                OldReaction = [||],
+                NewReaction = [| ReactionTypeEmoji(Emoji = reactionEmoji) |]
+            )
+        )
+
     static member spamPhoto =
         PhotoSize(
             FileId = "spam",

src/VahterBanBot/Bot.fs

@@ -1,4 +1,4 @@
-module VahterBanBot.Bot
+module VahterBanBot.Bot
 
 open System
 open System.Diagnostics
@@ -848,6 +848,24 @@ let onCallback
     do! botClient.AnswerCallbackQueryAsync(callbackQuery.Id)
 }
 
+let onMessageReaction (logger: ILogger) (reaction: MessageReactionUpdated) =
+    use _ =
+        botActivity
+            .StartActivity("messageReaction")
+            .SetTag("chatId", reaction.Chat.Id)
+            .SetTag("chatUsername", reaction.Chat.Username)
+            .SetTag("messageId", reaction.MessageId)
+            .SetTag("userId", reaction.User.Id)
+            .SetTag("userUsername", reaction.User.Username)
+    logger.LogInformation(
+        "Reaction from {Username} ({UserId}) on message {MessageId} in {ChatUsername} ({ChatId})",
+        reaction.User.Username,
+        reaction.User.Id,
+        reaction.MessageId,
+        reaction.Chat.Username,
+        reaction.Chat.Id
+    )
+
 let onUpdate
     (botUser: DbUser)
     (botClient: ITelegramBotClient)
@@ -859,6 +877,8 @@ let onUpdate
     use _ = botActivity.StartActivity("onUpdate")
     if update.CallbackQuery <> null then
         do! onCallback botClient botConfig logger update.CallbackQuery
+    elif update.MessageReaction <> null then
+        onMessageReaction logger update.MessageReaction
     else
         do! tryEnrichMessageWithOcr botClient botConfig computerVision logger update
         do! onMessage botUser botClient botConfig logger ml update.EditedOrMessage