From e583ee80845b8f69e1fab7a50401b2df70ddbe2d Mon Sep 17 00:00:00 2001
From: Haw Loeung <haw.loeung@canonical.com>
Date: Wed, 2 Nov 2022 09:30:18 +1100
Subject: [PATCH] Fallback to use API for getting channel data when not in the
 cache

---
 bridge/mattermost6/mattermost.go                    | 13 ++++++++++++-
 .../matterbridge/matterclient/channels.go           |  8 +++++++-
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/bridge/mattermost6/mattermost.go b/bridge/mattermost6/mattermost.go
index 0d9e4d32..ebc63ce6 100644
--- a/bridge/mattermost6/mattermost.go
+++ b/bridge/mattermost6/mattermost.go
@@ -563,7 +563,18 @@ func (m *Mattermost) GetChannel(channelID string) (*bridge.ChannelInfo, error) {
 		}
 	}
 
-	return nil, errors.New("channel not found")
+	// Fallback if it's not found in the cache.
+	mmchannel, _, err := m.mc.Client.GetChannel(channelID, "")
+	if err != nil {
+		return nil, errors.New("channel not found")
+	}
+	return &bridge.ChannelInfo{
+		Name:    mmchannel.Name,
+		ID:      mmchannel.Id,
+		TeamID:  mmchannel.TeamId,
+		DM:      mmchannel.IsGroupOrDirect(),
+		Private: !mmchannel.IsOpen(),
+	}, nil
 }
 
 func (m *Mattermost) GetUser(userID string) *bridge.UserInfo {
diff --git a/vendor/github.com/matterbridge/matterclient/channels.go b/vendor/github.com/matterbridge/matterclient/channels.go
index 6bf22a68..1ac242ba 100644
--- a/vendor/github.com/matterbridge/matterclient/channels.go
+++ b/vendor/github.com/matterbridge/matterclient/channels.go
@@ -80,7 +80,13 @@ func (m *Client) getChannelIDTeam(name string, teamID string) string {
 		}
 	}
 
-	return ""
+	// Fallback if it's not found in the t.Channels or t.MoreChannels cache.
+	// This also let's us join private channels.
+	channel, _, err := m.Client.GetChannelByName(name, teamID, "")
+	if err != nil {
+		return ""
+	}
+	return channel.Id
 }
 
 func (m *Client) GetChannelName(channelID string) string {