How to detect if HEAD points to an unborn branch?

Question

How can I detect if the current HEAD is an unborn branch?

"git rev-parse HEAD --" outputs

fatal: bad revision 'HEAD'

But git also outputs this for all other inputs like "git rev-parse noHEAD --".

"git branch" returns an empty output.

Do I have to read .git/HEAD and check if the contents start with "ref: " and the reference does not exist?

you could look here: http://stackoverflow.com/q/4848607/2082964, apparently `git branch -a` should say: Failed to resolve HEAD as a valid ref. This might help you further? — Chris Maes, Mar 04 '15 at 11:10
what does `git branch -a` give you? nothing that can help you further? otherwise I don't have another idea than parsing .git/HEAD :) — Chris Maes, Mar 04 '15 at 13:29

score 3 · Accepted Answer · answered Mar 04 '15 at 15:47

3

But git also outputs this for all other inputs like "git rev-parse noHEAD --".

The difference is that HEAD must exist, by definition, in a repository.

If you have a HEAD that is not a valid revision, then it must be pointing to a branch that is yet to be born.

For example:

> git checkout --orphan newbranch
> git rev-parse HEAD --
fatal: bad revision 'HEAD'

Versus if you have a branch checked out:

> git checkout master
> git rev-parse HEAD --

Versus if HEAD is nonexistent or damaged:

> git rev-parse HEAD --
fatal: Not a git repository (or any of the parent directories): .git

answered Mar 04 '15 at 15:47

Edward Thomson

How to fix this? – Aniket Kapse Sep 29 '20 at 09:41
You can fix a missing head like this `git symbolic-ref HEAD refs/heads/master` – Steve Pitchers Mar 06 '21 at 16:32

1 Answers1