I was trying to push to a canonical repository this morning and got the following error:
$ git push origin master
error: src refspec master matches more than one.
error: failed to push some refs to 'ssh://user@host/srv/git/repo'
This happened because I had accidentally created a master tag locally:
$ git tag
master
tag1
tag2
tag3
tag4
Once I deleted the tag locally:
tag -d master
I was able to push again.