Simple git push --tags deleted all branches

[Mateusz Loskot <mateusz@loskot.net>]

Hi,

(using git version 2.19.2.windows.1)

I've just encountered one of those WTH moments.

I have a bare repository

core.git (BARE:master) $ git branch
  1.0
  2.0
* master

core.git (BARE:master) $ git tag
1.0.1651
1.0.766
2.0.1103
2.0.1200

I published the repo using: git push --all --follow-tags

This succeeded, but there seem to be no tags pushed, just branches.
So, I followed with

core.git (BARE:master) $ git push --tags
To XXX
 - [deleted]               1.0
 - [deleted]               2.0
 ! [remote rejected]       master (refusing to delete the current
branch: refs/heads/master)
error: failed to push some refs to 'XXX'

And, I've found out that all branches and tags have been
wiped in both, local repo and remote :)

I restored the repo and tried out

git push origin 1.0
git push origin --tags

and this time both succeeded, without wiping out any refs.

Could anyone help me to understand why remote-less

git push --tags

is/was so dangerous and unforgiving?!

Best regards,
-- 
Mateusz Loskot, http://mateusz.loskot.net