MM-66424: Improve team filtering in common teams API (#34454) (#34854)

Cherry-pick 6404ab29acc04901c5cb1cf5ad97fc3c0693e2cd into release-10.11

server/public/model/client4.go

@@ -3637,6 +3637,23 @@ func (c *Client4) MoveChannel(ctx context.Context, channelId, teamId string, for
 	return ch, BuildResponse(r), nil
 }
 
+// GetGroupMessageMembersCommonTeams returns the set of teams in common for members of a GM channel.
+func (c *Client4) GetGroupMessageMembersCommonTeams(ctx context.Context, channelId string) ([]*Team, *Response, error) {
+	r, err := c.DoAPIGet(ctx, c.channelRoute(channelId)+"/common_teams", "")
+	if err != nil {
+		return nil, BuildResponse(r), err
+	}
+	defer closeBody(r)
+
+	var teams []*Team
+	err = json.NewDecoder(r.Body).Decode(&teams)
+	if err != nil {
+		return nil, BuildResponse(r), NewAppError("GetGroupMessageMembersCommonTeams", "api.marshal_error", nil, "", http.StatusInternalServerError).Wrap(err)
+	}
+
+	return teams, BuildResponse(r), nil
+}
+
 // GetChannelByName returns a channel based on the provided channel name and team id strings.
 func (c *Client4) GetChannelByName(ctx context.Context, channelName, teamId string, etag string) (*Channel, *Response, error) {
 	r, err := c.DoAPIGet(ctx, c.channelByNameRoute(channelName, teamId), etag)

server/public/model/example_channel_test.go

@@ -491,3 +491,19 @@ func ExampleClient4_UpdateChannelScheme() {
 		log.Fatal(err)
 	}
 }
+
+func ExampleClient4_GetGroupMessageMembersCommonTeams() {
+	client := model.NewAPIv4Client(os.Getenv("MM_SERVICESETTINGS_SITEURL"))
+	client.SetToken(os.Getenv("MM_AUTHTOKEN"))
+
+	channelID := "gm_channel_id"
+	teams, _, err := client.GetGroupMessageMembersCommonTeams(context.Background(), channelID)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	fmt.Printf("Found %d common teams for members of channel %s\n", len(teams), channelID)
+	for _, team := range teams {
+		fmt.Printf("  - %s (%s)\n", team.DisplayName, team.Name)
+	}
+}