Cann't sync gitlab project which has the same name with it's parent group

For example, I have a Group named ‘test’, then a project under it also named ‘test’.

Then the Drone can’t sync it

drone version 1.1.0

Can’t sync gitlab project which has the same name with it’s parent group

I think you are mis-diagnosing the problem. There are well documented reasons that syncing can fail [1] and this is not one of them. Also consider the name of the Drone repository is drone/drone and it syncs just fine [2][3].

[1] https://github.com/drone/drone/issues/2658#issuecomment-487129881
[2] https://github.com/drone/drone
[3] https://cloud.drone.io/drone/drone