From 79e4959d022114e26ea6349143c37ace708003a4 Mon Sep 17 00:00:00 2001
From: Zubair Ahmed <m-zubairahmed@protonmail.com>
Date: Wed, 2 Nov 2022 15:10:51 +0530
Subject: [PATCH] Return empty list of channels when requesting more channels
 at the end of cursor (#21557)

---
 api4/resolver_channel_test.go    |  2 +-
 app/channel.go                   |  9 +--------
 store/sqlstore/channel_store.go  |  4 ----
 store/storetest/channel_store.go | 16 ++++++++++++++++
 4 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/api4/resolver_channel_test.go b/api4/resolver_channel_test.go
index d5a55dee16..7ecc12f06b 100644
--- a/api4/resolver_channel_test.go
+++ b/api4/resolver_channel_test.go
@@ -310,7 +310,7 @@ func TestGraphQLChannels(t *testing.T) {
 
 		resp, err = th.MakeGraphQLRequest(&input)
 		require.NoError(t, err)
-		require.Len(t, resp.Errors, 1) // no channels found
+		require.Len(t, resp.Errors, 0) // no errors for no channels found
 
 		th.BasicChannel.Purpose = "newpurpose"
 		_, _, err = th.Client.UpdateChannel(th.BasicChannel)
diff --git a/app/channel.go b/app/channel.go
index 504c7265d6..64d61c20aa 100644
--- a/app/channel.go
+++ b/app/channel.go
@@ -1876,15 +1876,8 @@ func (a *App) GetChannelsForTeamForUser(c request.CTX, teamID string, userID str
 func (a *App) GetChannelsForTeamForUserWithCursor(c request.CTX, teamID string, userID string, opts *model.ChannelSearchOpts, afterChannelID string) (model.ChannelList, *model.AppError) {
 	list, err := a.Srv().Store().Channel().GetChannelsWithCursor(teamID, userID, opts, afterChannelID)
 	if err != nil {
-		var nfErr *store.ErrNotFound
-		switch {
-		case errors.As(err, &nfErr):
-			return nil, model.NewAppError("GetChannelsForUser", "app.channel.get_channels.not_found.app_error", nil, "", http.StatusNotFound).Wrap(err)
-		default:
-			return nil, model.NewAppError("GetChannelsForUser", "app.channel.get_channels.get.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
-		}
+		return nil, model.NewAppError("GetChannelsForUser", "app.channel.get_channels.get.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
 	}
-
 	return list, nil
 }
 
diff --git a/store/sqlstore/channel_store.go b/store/sqlstore/channel_store.go
index 78db001082..cfd30c85c2 100644
--- a/store/sqlstore/channel_store.go
+++ b/store/sqlstore/channel_store.go
@@ -1110,10 +1110,6 @@ func (s SqlChannelStore) GetChannelsWithCursor(teamId string, userId string, opt
 		return nil, errors.Wrapf(err, "failed to get channels with TeamId=%s and UserId=%s", teamId, userId)
 	}
 
-	if len(channels) == 0 {
-		return nil, store.NewErrNotFound("Channel", "userId="+userId)
-	}
-
 	return channels, nil
 }
 
diff --git a/store/storetest/channel_store.go b/store/storetest/channel_store.go
index 2138f011ed..c1843bc8be 100644
--- a/store/storetest/channel_store.go
+++ b/store/storetest/channel_store.go
@@ -3566,6 +3566,22 @@ func testChannelStoreGetChannelsWithCursor(t *testing.T, ss store.Store) {
 	require.Len(t, list, 1)
 	require.Equal(t, teamID, list[0].TeamId, "incorrect teamID")
 
+	// all channels should be returned
+	list, nErr = ss.Channel().GetChannelsWithCursor(o1.TeamId, m1.UserId, &model.ChannelSearchOpts{
+		IncludeDeleted: false,
+		LastDeleteAt:   0,
+	}, "")
+	require.NoError(t, nErr)
+	require.Len(t, list, 3)
+
+	// should return empty list
+	list, nErr = ss.Channel().GetChannelsWithCursor(o1.TeamId, m1.UserId, &model.ChannelSearchOpts{
+		IncludeDeleted: false,
+		LastDeleteAt:   0,
+	}, list[2].Id)
+	require.NoError(t, nErr)
+	require.Len(t, list, 0)
+
 	// Sleeping to guarantee that the
 	// UpdateAt is different.
 	// The proper way would be to set UpdateAt during channel creation itself,