From 390f9f422e2310cde527155dd1627087744932a4 Mon Sep 17 00:00:00 2001
From: Tulir Asokan <tulir@maunium.net>
Date: Wed, 10 Dec 2025 19:40:39 +0200
Subject: [PATCH] backfill: clear saved takeout ID on takeout invalid error

---
 pkg/connector/backfill.go | 33 +++++++++++++++++++++++++--------
 pkg/connector/metadata.go |  3 +++
 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/pkg/connector/backfill.go b/pkg/connector/backfill.go
index 3e159ca9..86b93967 100644
--- a/pkg/connector/backfill.go
+++ b/pkg/connector/backfill.go
@@ -41,6 +41,10 @@ var (
 
 // getTakeoutID blocks until the takeout ID is available.
 func (t *TelegramClient) getTakeoutID(ctx context.Context) (takeoutID int64, err error) {
+	if t.metadata.TakeoutInvalidated {
+		// TODO should we just backfill without takeout here?
+		return 0, fmt.Errorf("takeout invalidated, cannot backfill")
+	}
 	// Always stop the takeout timeout timer
 	if t.stopTakeoutTimer != nil {
 		t.stopTakeoutTimer.Stop()
@@ -193,6 +197,7 @@ func (t *TelegramClient) FetchMessages(ctx context.Context, fetchParams bridgev2
 
 	var takeoutID int64
 	var err error
+	// TODO use takeout for forward backfill if already available
 	if !fetchParams.Forward { // Backwards
 		t.takeoutLock.Lock()
 		defer t.takeoutLock.Unlock()
@@ -201,13 +206,15 @@ func (t *TelegramClient) FetchMessages(ctx context.Context, fetchParams bridgev2
 			return nil, err
 		}
 
-		defer func() {
-			if t.stopTakeoutTimer == nil {
-				t.stopTakeoutTimer = time.AfterFunc(max(time.Hour, time.Duration(t.main.Bridge.Config.Backfill.Queue.BatchDelay*2)), sync.OnceFunc(func() { t.stopTakeout(ctx) }))
-			} else {
-				t.stopTakeoutTimer.Reset(max(time.Hour, time.Duration(t.main.Bridge.Config.Backfill.Queue.BatchDelay*2)))
-			}
-		}()
+		if takeoutID != 0 {
+			defer func() {
+				if t.stopTakeoutTimer == nil {
+					t.stopTakeoutTimer = time.AfterFunc(max(time.Hour, time.Duration(t.main.Bridge.Config.Backfill.Queue.BatchDelay*2)), sync.OnceFunc(func() { t.stopTakeout(ctx) }))
+				} else {
+					t.stopTakeoutTimer.Reset(max(time.Hour, time.Duration(t.main.Bridge.Config.Backfill.Queue.BatchDelay*2)))
+				}
+			}()
+		}
 	}
 
 	peer, topicID, err := t.inputPeerForPortalID(ctx, fetchParams.Portal.ID)
@@ -248,7 +255,7 @@ func (t *TelegramClient) FetchMessages(ctx context.Context, fetchParams bridgev2
 			OffsetID: offsetID,
 		}
 	}
-	if !fetchParams.Forward {
+	if takeoutID != 0 {
 		req = &tg.InvokeWithTakeoutRequest{TakeoutID: takeoutID, Query: req}
 	}
 	log.Info().Any("req", req).Msg("Fetching messages")
@@ -265,6 +272,16 @@ func (t *TelegramClient) FetchMessages(ctx context.Context, fetchParams bridgev2
 		return msgs, nil
 	})
 	if err != nil {
+		if tgerr.Is(err, tg.ErrTakeoutInvalid) {
+			t.metadata.TakeoutID = 0
+			t.metadata.TakeoutInvalidated = true
+			err := t.userLogin.Save(ctx)
+			if err != nil {
+				log.Err(err).Msg("Failed to save user login after clearing takeout ID")
+			} else {
+				log.Debug().Msg("Cleared invalid takeout ID")
+			}
+		}
 		return nil, err
 	}
 
diff --git a/pkg/connector/metadata.go b/pkg/connector/metadata.go
index debde235..a708ada5 100644
--- a/pkg/connector/metadata.go
+++ b/pkg/connector/metadata.go
@@ -80,6 +80,8 @@ type UserLoginMetadata struct {
 	Session     UserLoginSession `json:"session"`
 	TakeoutID   int64            `json:"takeout_id,omitempty"`
 
+	TakeoutInvalidated bool `json:"takeout_invalidated,omitempty"`
+
 	TakeoutDialogCrawlDone   bool               `json:"takeout_portal_crawl_done,omitempty"`
 	TakeoutDialogCrawlCursor networkid.PortalID `json:"takeout_portal_crawl_cursor,omitempty"`
 
@@ -92,6 +94,7 @@ func (u *UserLoginMetadata) ResetOnLogout() {
 	u.Session.AuthKey = nil
 	u.TakeoutID = 0
 	u.TakeoutDialogCrawlDone = false
+	u.TakeoutInvalidated = false
 	u.TakeoutDialogCrawlCursor = networkid.PortalID("")
 	u.PushEncryptionKey = nil
 }