Re: Obscure error/warning/information message from git pull

[Tassilo Horn <tsdh@gnu.org>]

Alan Mackenzie <acm@muc.de> writes:

>> > This doesn't work very well.  It prints out the information for the first
>> > commit that is displayed, but no more.  This feels like a git bug.
>
>> No, this is the correct behaviour.
>
> So, not very useful, then.  Also not what the FM says:
>
>     "Print out the ref names of any commits that are shown."
>
> .  Not one commit, but any (i.e. all) commits.  Of course, that's all
> dependent on knowing what "ref name" means.  I suppose you're going to
> tell me next that only the first commit actually has a "ref name"
> (whatever that is).  But if you do, it would be really nice if you
> could explain what is meant by "ref name", or even point me at a non
> content-free definition.  :-)

I'd say a ref name is a name for a commit which has some special
meaning.  Then you can use the ref name instead of the SHA1 to operate
on it.

For example, HEAD is the ref name for the most recent commit in the
current branch, and a branch is actually only a ref name for some
commit.  HEAD is called a symbolic ref because its value is a ref name
again.  That's what I get in the emacs-24 branch:

  % cat .git/HEAD .git/refs/heads/emacs-24 
  ref: refs/heads/emacs-24
  4cd0f2dc6f868bc76c2326db1a16b3bb21f78024

And any tag is a ref name, too.  When you do "git log --decorate" in the
emacs-24 branch, you'll see more decorated commits, e.g.,:

commit 83bad90efe943e7c88431b7a71bc1d5cf1304c92 (tag: emacs-24.4)
Author: Glenn Morris <rgm@gnu.org>
Date:   Mon Oct 20 20:21:15 2014 +0100

    Add 24.4 release ChangeLog entries

commit 9b4fdfd9b67aa9e370cd20e0188f08678daa665c (tag: emacs-24.4-rc1)
Author: Glenn Morris <rgm@gnu.org>
Date:   Fri Oct 17 09:08:40 2014 -0700

    Regenerate ldefs-boot

That's explained well in the git book at

  http://git-scm.com/book/en/v2/Git-Internals-Git-References

HTH,
Tassilo