Import/Export - Moving from self-hosted Gitlab instance to Gitlab.com does not preserve authors and assignees
Description of the problem
I need to transfer a project from a self-hosted Gitlab instance to Gitlab.com into a private project.
There is the same group on the self-hosted instance and Gitlab.com with matching username and email for the 4 contributors (including me). All contributors are owners of the group.
I tried to use the import/export feature.
The import succeed but all issues, merge requests and comments are authored by my user and a note with the original author is appended, the users mapping does not work.
The documentation on the import/export feature says:
An admin in the import side is required to map the users, based on email or username. Otherwise, a supplementary comment is left to mention the original author and the MRs, notes or issues will be owned by the importer.
Is there a way to make the users mapping work for imported projects on Gitlab.com ?