git refusing to fetch into current branch

Question

I set up a remote repository and I can push new changes to it, but I cannot fetch from it, I always get the (rather cryptic) error message:

fatal: Refusing to fetch into current branch refs/heads/master of non-bare repository
fatal: The remote end hung up unexpectedly

What does it mean? What should I do to enable fetching?

(Note that this remote repo is only used as a backup repo, so it should be pretty much an exact copy of my local repository. I really can't understand why I can push to it but not fetch from it...)

My config looks like:

[remote "origin"]
    url = ssh://blablablah
    fetch = +refs/*:refs/*
    mirror = true

Answer 1

In case anyone finds this because they specifically want to fetch into the current branch, you can use the --update-head-ok flag. From the docs:

-u
--update-head-ok
By default git fetch refuses to update the head which corresponds to the current branch. This flag disables the check. This is purely for the internal use for git pull to communicate with git fetch, and unless you are implementing your own Porcelain you are not supposed to use it.

In some cases we do want to implement our own porcelain commands, e.g., automation and tooling.