Fix bug in SqlPostStore.PermanentDeletebyUser where no error was returned when 10K posts was exceeded. Remaining posts were silently orphaned. (#29642)

Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/store/sqlstore/post_store.go

@@ -1065,6 +1065,7 @@ func (s *SqlPostStore) PermanentDeleteByUser(rctx request.CTX, userId string) er
 
 	// Now attempt to delete all the root posts for a user. This will also
 	// delete all the comments for each post
+	const maxLoops = 10
 	count := 0
 	for {
 		var ids []string
@@ -1083,8 +1084,8 @@ func (s *SqlPostStore) PermanentDeleteByUser(rctx request.CTX, userId string) er
 
 		// This is a fail safe, give up if more than 10k messages
 		count++
-		if count >= 10 {
+		if count >= maxLoops {
-			return errors.Wrapf(err, "too many Posts to delete with userId=%s", userId)
+			return store.NewErrLimitExceeded("permanently deleting posts for user", maxLoops*1000, "userId="+userId)
 		}
 	}
 

server/channels/store/storetest/post_store.go

@@ -31,6 +31,7 @@ func TestPostStore(t *testing.T, rctx request.CTX, ss store.Store, s SqlStore) {
 	t.Run("Delete", func(t *testing.T) { testPostStoreDelete(t, rctx, ss) })
 	t.Run("PermDelete1Level", func(t *testing.T) { testPostStorePermDelete1Level(t, rctx, ss) })
 	t.Run("PermDelete1Level2", func(t *testing.T) { testPostStorePermDelete1Level2(t, rctx, ss) })
+	t.Run("PermDeleteLimitExceeded", func(t *testing.T) { testPostStorePermDeleteLimitExceeded(t, rctx, ss) })
 	t.Run("GetWithChildren", func(t *testing.T) { testPostStoreGetWithChildren(t, rctx, ss) })
 	t.Run("GetPostsWithDetails", func(t *testing.T) { testPostStoreGetPostsWithDetails(t, rctx, ss) })
 	t.Run("GetPostsBeforeAfter", func(t *testing.T) { testPostStoreGetPostsBeforeAfter(t, rctx, ss) })
@@ -1686,6 +1687,33 @@ func testPostStorePermDelete1Level2(t *testing.T, rctx request.CTX, ss store.Sto
 	require.NoError(t, err, "Deleted id should have failed")
 }
 
+func testPostStorePermDeleteLimitExceeded(t *testing.T, rctx request.CTX, ss store.Store) {
+	const maxPosts = 10000
+	teamID := model.NewId()
+	userID := model.NewId()
+	channel, err := ss.Channel().Save(rctx, &model.Channel{
+		TeamId:      teamID,
+		DisplayName: "10KPosts",
+		Name:        "channel" + model.NewId(),
+		Type:        model.ChannelTypeOpen,
+	}, -1)
+	require.NoError(t, err)
+
+	for i := 0; i < maxPosts+100; i++ {
+		post := &model.Post{
+			ChannelId: channel.Id,
+			UserId:    userID,
+			Message:   NewTestID(),
+		}
+		_, err = ss.Post().Save(rctx, post)
+		require.NoError(t, err)
+	}
+
+	err = ss.Post().PermanentDeleteByUser(rctx, userID)
+	var errLimitExceeded *store.ErrLimitExceeded
+	require.ErrorAs(t, err, &errLimitExceeded)
+}
+
 func testPostStoreGetWithChildren(t *testing.T, rctx request.CTX, ss store.Store) {
 	teamID := model.NewId()
 	channel1, err := ss.Channel().Save(rctx, &model.Channel{