Hi,
I have the same problem like “Fatal error: Call to undefined function bp_get_current_group_id() in /home/…/public_html/…/wp-content/plugins/buddypress/bp-groups/classes/class-bp-group-extension.php on line 484”. The solution given above can fixed the issue, but it is affecting when i am updating the plugin. So, how can i override this file inside the theme so that the change wont lose when i update the plugin buddypress.