fix(telegram): retry transient 5xx download errors

extensions/telegram/src/bot/delivery.resolve-media-retry.test.ts

@@ -239,6 +239,31 @@ describe("resolveMedia getFile retry", () => {
     expect(fetchRemoteMedia).toHaveBeenCalledTimes(1);
   });
 
+  it("retries fetchRemoteMedia on transient HTTP 5xx error and succeeds", async () => {
+    const getFile = vi.fn().mockResolvedValue({ file_path: "voice/file_0.oga" });
+    fetchRemoteMedia
+      .mockRejectedValueOnce(new MockMediaFetchError("http_error", "HTTP 502 Bad Gateway"))
+      .mockResolvedValueOnce({
+        buffer: Buffer.from("audio"),
+        contentType: "audio/ogg",
+        fileName: "file_0.oga",
+      });
+    saveMediaBuffer.mockResolvedValueOnce({
+      path: "/tmp/file_0.oga",
+      contentType: "audio/ogg",
+    });
+
+    const promise = resolveMedia(makeCtx("voice", getFile), MAX_MEDIA_BYTES, BOT_TOKEN);
+    await flushRetryTimers();
+    const result = await promise;
+
+    expect(getFile).toHaveBeenCalledTimes(1);
+    expect(fetchRemoteMedia).toHaveBeenCalledTimes(2);
+    expect(result).toEqual(
+      expect.objectContaining({ path: "/tmp/file_0.oga", placeholder: "<media:audio>" }),
+    );
+  });
+
   it("does not retry fetchRemoteMedia on max_bytes policy violation", async () => {
     const getFile = vi.fn().mockResolvedValue({ file_path: "video/large.mp4" });
     fetchRemoteMedia.mockRejectedValueOnce(

extensions/telegram/src/bot/delivery.resolve-media.ts

@@ -66,9 +66,19 @@ function isRetryableGetFileError(err: unknown): boolean {
  */
 function isRetryableDownloadError(err: unknown): boolean {
   if (err instanceof MediaFetchError) {
-    // Only retry transient fetch failures (network issues, timeouts, connection drops).
-    // Do not retry HTTP errors (4xx, 5xx) or policy violations (max_bytes).
-    return err.code === "fetch_failed";
+    // Retry transient fetch failures (network issues, timeouts, connection drops).
+    if (err.code === "fetch_failed") {
+      return true;
+    }
+    // Retry transient HTTP 5xx server errors; do not retry 4xx or policy violations.
+    if (err.code === "http_error") {
+      const match = /HTTP (\d{3})/.exec(err.message);
+      if (match) {
+        const status = Number(match[1]);
+        return status >= 500;
+      }
+    }
+    return false;
   }
   // For non-MediaFetchError, check if it looks like a transient network error.
   const msg = formatErrorMessage(err).toLowerCase();