[tex-live] tlmgr not correctly set-up for out-of-the box use with locally mirrored repository

[jfbu]

Hi,

I did an install of TLpretest via rsync'ing a mirror.

Today I wanted to update my local installation (after
having update my rsynced mirror) but I got this :

$ tlmgr update --all
tlmgr: package repository /usr/local/texlive/2018 (not verified: unknown)
tlmgr: saving backups to /usr/local/texlive/2018/tlpkg/backups
tlmgr: no updates available
tlmgr: Your installation is set up to look on the disk for updates.
To install from the Internet for this one time only, run:
  tlmgr -repository http://mirror.ctan.org/systems/texlive/tlnet ACTION ARG...
where ACTION is install, update, etc.; see tlmgr -help if needed.

To change the default for all future updates, run:
  tlmgr option repository http://mirror.ctan.org/systems/texlive/tlnet

Then I checked:

$ tlmgr option repository
Default package repository (repository): .

Finally I have some notes from similar situation in 2016, so I did

$ tlmgr option repository ~/zzzzzz/TLmirror
tlmgr: setting default package repository to /yyyyyy/xxxxxx/zzzzzz/TLmirror

Then

$ tlmgr update --all
tlmgr: package repository /yyyyyy/xxxxxx/zzzzzz/TLmirror (verified)
tlmgr: saving backups to /usr/local/texlive/2018/tlpkg/backups
[1/9, ??:??/??:??] update: a2ping [67k] (29725 -> 46893) ... done
....

In the meantime I had tried to do the update from the ~/zzzzzz/TLmirror
repertory, thinking that maybe it would match the "." which was reported
above on querying the repository option. But to no avail.

Best,

Jean-François