v2.9.3 and v2.10.0: `name-ref' HEAD gives wrong branch name

Hello again,

yah, sorry, i'm back again.. I try to find a way to find the name of the current branch in an automated way, because i need to ensure that a commit happens on it and no other branch. Now the problem arises that the commit ref at the time of that commit maybe shared in between several different branches, but no more thereafter, of course:

  ?0[steffen@wales ]$ git branch|grep '^*'
  * stable/v14.9
  ?0[steffen@wales ]$ git name-rev --name-only HEAD
  stable/v14.8

Is there another way except looking into .git/HEAD or using sed(1) on the output of `branch' to find the right name? Thank you. Ciao!

--steffen

On Tue, Sep 20, 2016 at 9:23 AM, Steffen Nurpmeso <steffen@sdaoden.eu> wrote:

Have you tried "git symbolic-ref HEAD"?

$ git symbolic-ref HEAD refs/heads/master

If you don't want the fully-qualified ref, you can add --short:

$ git symbolic-ref --short HEAD master

Hey.

Bryan Turner <bturner@atlassian.com> wrote:
 |On Tue, Sep 20, 2016 at 9:23 AM, Steffen Nurpmeso <steffen@sdaoden.eu> \
 |wrote:
 |> yah, sorry, i'm back again..
 |> I try to find a way to find the name of the current branch in an
 |> automated way, because i need to ensure that a commit happens on
 |> it and no other branch.  Now the problem arises that the commit
 |> ref at the time of that commit maybe shared in between several
 |> different branches, but no more thereafter, of course:
 |>
 |>   ?0[steffen@wales ]$ git branch|grep '^*'
 |>   * stable/v14.9
 |>   ?0[steffen@wales ]$ git name-rev --name-only HEAD
 |>   stable/v14.8
 |>
 |> Is there another way except looking into .git/HEAD or using sed(1)
 |> on the output of `branch' to find the right name?
 |
 |Have you tried "git symbolic-ref HEAD"?

Not until now.

 |$ git symbolic-ref HEAD
 |refs/heads/master

Works.

 |If you don't want the fully-qualified ref, you can add --short:
 |
 |$ git symbolic-ref --short HEAD
 |master

Yep, works even better. Fantastic. Thank you. And that command was already existing when i have learned to use git(1), it is even in the progit-09.markdown as of 2011-09-22 that i have laying around. Five years, and anything forgotten. That is what you get from working with blinkers on. Shame!

Thank you Bryan.

--steffen

W dniu 20.09.2016 o 20:54, Bryan Turner pisze:

Not good, 'git branch' is a porcelain (user facing) command, so it output may change; e.g. '*' could be replaced with '•'. For example output for detached HEAD had changed!

This does not work for detached HEAD, but perhaps you don't need to worry about this.

  $ git rev-parse --symbolic-full-name HEAD
  refs/heads/master

But

  $ git checkout HEAD^0
  Note: checking out 'HEAD^0'.

  You are in 'detached HEAD' state. [...]
 
  $ git rev-parse --symbolic-full-name HEAD
  HEAD

  $ git symbolic-ref HEAD
  fatal: ref HEAD is not a symbolic ref

  $ git branch
  * (HEAD detached at 3e2ebf9)
    master

Hello.

Jakub Narębski <jnareb@gmail.com> wrote:
 |W dniu 20.09.2016 o 20:54, Bryan Turner pisze:
 |> On Tue, Sep 20, 2016 at 9:23 AM, Steffen Nurpmeso <steffen@sdaoden.eu> \
 |> wrote:
 |>> Hello again,
 |>>
 |>> yah, sorry, i'm back again..
 |>> I try to find a way to find the name of the current branch in an
 |>> automated way, because i need to ensure that a commit happens on
 |>> it and no other branch.  Now the problem arises that the commit
 |>> ref at the time of that commit maybe shared in between several
 |>> different branches, but no more thereafter, of course:
 |>>
 |>>   ?0[steffen@wales ]$ git branch|grep '^*'
 |>>   * stable/v14.9
 |
 |Not good, 'git branch' is a porcelain (user facing) command, so it
 |output may change; e.g. '*' could be replaced with '•'. For example
 |output for detached HEAD had changed!

Ok. I went the road Bryan suggested, i had only forgotten this. Yes, it caused mysterious bugs once rev-parse reversed the output, but i didn't understand the order at first, anyway. With todays' ever-rotating distributions i don't even try to keep up; currently unthinkable to use the same release of an OS for five years, like FreeBSD 5.3. Well.

  ...
 |>> Is there another way except looking into .git/HEAD or using sed(1)
 |>> on the output of `branch' to find the right name?
 |> 
 |> Have you tried "git symbolic-ref HEAD"?
  ...
 |This does not work for detached HEAD, but perhaps you don't need
 |to worry about this.

No, not for me: it will only switch in between two different stable/ which exist. But thanks, just give it to me!

 |  $ git rev-parse --symbolic-full-name HEAD
 |  refs/heads/master

This is a really good suggestion, which i will remember. I didn't know this at all yet:

  $ git rev-parse --symbolic-full-name --abbrev-ref=strict HEAD

Seems to do exactly what i want, non-fragile, then.

 ...
 |But
 ...
 |  You are in 'detached HEAD' state. [...]
 | 
 |  $ git rev-parse --symbolic-full-name HEAD
 |  HEAD
 |
 |  $ git symbolic-ref HEAD
 |  fatal: ref HEAD is not a symbolic ref
 |
 |  $ git branch
 |  * (HEAD detached at 3e2ebf9)
 |    master

And name-rev gives "HEAD master~2" in a test of mine, or only "master~2", or "undefined" if i use --tags, for completeness sake.

Thanks, Jakub.  I'm using the plumbing.

--steffen

Jakub Narębski <jnareb@gmail.com> writes:

I am not sure what you mean by "does not work". Asking what ref HEAD points at to symbolic-ref will tell you it does not point at anything by exiting with non-zero status and that can be relied upon.

Asking "symbolic-ref HEAD" has been the way how "git branch" and other commands find out what branch is currently checked out for almost eternity ("git symbolic-ref" appeared in Git v0.99.8).

W dniu 21.09.2016 o 18:37, Junio C Hamano pisze:

I'm sorry, I was wrong saying "does not work". The problem is not that it does not work, but that you need to take care of exit condition to correctly support detached HEAD state, and not end with empty name for a branch, for example...

But if handled correctly, git-symbolic-ref is as good as git-rev-parse as a plumbing to resolve current branch name.

Best,