Git error when pushing - update_ref failed

Question

I have a problem when i try to push my local commits, it has probably happened when Android Studio has crushed. Here is the error:

update_ref failed for ref 'refs/remotes/origin/master': cannot lock ref 'refs/remotes/origin/master': unable to resolve reference refs/remotes/origin/master: Invalid argument

$git stash says that HEAD is now at my latest commit.

I'm still a beginner in git and I have no idea how to fix it.. What can I do?

Answer 1

Your refs/remotes/origin directory—this is a directory within in your local repository—has some sort of problem. (It's not clear to me what exactly went wrong, but your guess that it happened when Android Studio crashed seems likely to me as well.)

To fix it, you can probably use the sequence of commands below. Note that I don't recommend it in general—your Git service, whether that's Android Studio or ordinary command-line Git, is not supposed to crash and leave you with a broken repository, so you should never have to do this, it's just an emergency repair, something like putting duct tape all over your car¹ after a tree fell on it, just enough to get you to a proper repair / replacement vehicle later:

$ cd $(git rev-parse --show-toplevel)  # if necessary
$ rm -rf .git/refs/remotes/origin      # remove all origin/*
$ mkdir .git/refs/remotes/origin       # create empty origin/
$ git fetch origin                     # repopulate origin/*

In any case it's likely that your git push has actually succeeded at this point, since what is failing is the update to your origin/master remote-tracking branch.

Your Git has just finished talking to another Git on origin, giving them (the users of origin) updates for their master, and origin has accepted those updates, and your Git is now recording the fact that, the last time it talked with origin, their master was set to some particular commit hash—the one you just pushed.

(Remember that your origin/* remote-tracking branches are just recording, for you, what your Git saw that their Git has for its branches. Your Git updates these when you run git fetch, where your Git talks to their Git and gets all of its branches. Your git also updates some—not all—on git push, when your Git talks to their Git and asks them to set one or more branches, to the hashes your Git hands them.)

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¹Except that as a Git mechanic, instead of just duct tape, baling wire, and chewing gum, my recommended parts are actually proper body panels, belts and hoses, and clamps. :-)