fix(telegram): preserve final overflow state

obviyus · obviyus · commit 4dc235428594 · 2026-05-28T13:17:57.000Z
diff --git a/extensions/telegram/src/draft-stream.test.ts b/extensions/telegram/src/draft-stream.test.ts
@@ -505,6 +505,25 @@ describe("createTelegramDraftStream", () => {
     );
   });
 
+  it("continues finalizing more than two overflow chunks after a clamped preview", async () => {
+    const api = createMockDraftApi();
+    api.sendMessage
+      .mockResolvedValueOnce({ message_id: 17 })
+      .mockResolvedValueOnce({ message_id: 42 })
+      .mockResolvedValueOnce({ message_id: 43 });
+    const stream = createDraftStream(api, { maxChars: 10 });
+
+    stream.update("1234567890ABCDEFGHIJKLMNOPQRST");
+    await stream.flush();
+    await stream.stop();
+
+    expect(api.sendMessage).toHaveBeenCalledTimes(3);
+    expect(api.sendMessage).toHaveBeenNthCalledWith(1, 123, "1234567890", undefined);
+    expect(api.sendMessage).toHaveBeenNthCalledWith(2, 123, "ABCDEFGHIJ", undefined);
+    expect(api.sendMessage).toHaveBeenNthCalledWith(3, 123, "KLMNOPQRST", undefined);
+    expect(stream.lastDeliveredText?.()).toBe("1234567890ABCDEFGHIJKLMNOPQRST");
+  });
+
   it("retains final overflow preview pages", async () => {
     const api = createMockDraftApi();
     api.sendMessage
diff --git a/extensions/telegram/src/draft-stream.ts b/extensions/telegram/src/draft-stream.ts
@@ -117,7 +117,11 @@ export function createTelegramDraftStream(params: {
   let previewRevision = 0;
   let generation = 0;
   let deliveredTextOffset = 0;
-  let resetStreamToNewMessage: (options?: { keepPending?: boolean; resetOffset?: boolean }) => void;
+  let resetStreamToNewMessage: (options?: {
+    keepFinal?: boolean;
+    keepPending?: boolean;
+    resetOffset?: boolean;
+  }) => void;
   type PreviewSendParams = {
     renderedText: string;
     renderedParseMode: "HTML" | undefined;
@@ -227,7 +231,7 @@ export function createTelegramDraftStream(params: {
         const supersededParseMode = lastSentParseMode;
         const supersededVisibleSinceMs = streamVisibleSinceMs;
         deliveredTextOffset = lastDeliveredText.length;
-        resetStreamToNewMessage({ keepPending: true, resetOffset: false });
+        resetStreamToNewMessage({ keepFinal: true, keepPending: true, resetOffset: false });
         if (typeof supersededMessageId === "number") {
           params.onSupersededPreview?.({
             messageId: supersededMessageId,
@@ -314,7 +318,7 @@ export function createTelegramDraftStream(params: {
 
   resetStreamToNewMessage = (options) => {
     streamState.stopped = false;
-    streamState.final = false;
+    streamState.final = options?.keepFinal === true;
     generation += 1;
     messageSendAttempted = false;
     streamMessageId = undefined;
