fix: preserve explicit Telegram topic targets on replies (#59634) (thanks @dashhuang)

extensions/telegram/src/action-threading.test.ts

@@ -17,7 +17,7 @@ describe("resolveTelegramAutoThreadId", () => {
   it("matches chats across Telegram target formats", () => {
     expect(
       resolveTelegramAutoThreadId({
-        to: "telegram:group:-100123:topic:77",
+        to: "telegram:group:-100123",
         toolContext: createToolContext(),
       }),
     ).toBe("thread-1");
@@ -36,4 +36,13 @@ describe("resolveTelegramAutoThreadId", () => {
       }),
     ).toBeUndefined();
   });
+
+  it("does not override an explicit target topic", () => {
+    expect(
+      resolveTelegramAutoThreadId({
+        to: "telegram:group:-100123:topic:77",
+        toolContext: createToolContext(),
+      }),
+    ).toBeUndefined();
+  });
 });

extensions/telegram/src/action-threading.ts

@@ -9,6 +9,9 @@ export function resolveTelegramAutoThreadId(params: {
     return undefined;
   }
   const parsedTo = parseTelegramTarget(params.to);
+  if (parsedTo.messageThreadId != null) {
+    return undefined;
+  }
   const parsedChannel = parseTelegramTarget(context.currentChannelId);
   if (parsedTo.chatId.toLowerCase() !== parsedChannel.chatId.toLowerCase()) {
     return undefined;

extensions/telegram/src/channel.test.ts

@@ -268,6 +268,20 @@ describe("telegramPlugin threading", () => {
 
     expect(resolved).toBe("533274");
   });
+
+  it("does not override an explicit target topic when replyToId is present", () => {
+    const resolved = telegramPlugin.threading?.resolveAutoThreadId?.({
+      cfg: createCfg(),
+      to: "telegram:-1001:topic:99",
+      replyToId: "4103",
+      toolContext: {
+        currentChannelId: "telegram:-1001:topic:77",
+        currentThreadTs: "77",
+      },
+    });
+
+    expect(resolved).toBeUndefined();
+  });
 });
 
 describe("telegramPlugin bindings", () => {