git/Documentation/git-symbolic-ref.txt
Junio C Hamano b77e3bdd97 symbolic-ref: teach "--[no-]recurse" option
Suppose you are managing many maintenance tracks in your project,
and some of the more recent ones are maint-2.36 and maint-2.37.
Further imagine that your project recently tagged the official 2.38
release, which means you would need to start maint-2.38 track soon,
by doing:

  $ git checkout -b maint-2.38 v2.38.0^0
  $ git branch --list 'maint-2.3[6-9]'
  * maint-2.38
    maint-2.36
    maint-2.37

So far, so good.  But it also is reasonable to want not to have to
worry about which maintenance track is the latest, by pointing a
more generic-sounding 'maint' branch at it, by doing:

  $ git symbolic-ref refs/heads/maint refs/heads/maint-2.38

which would allow you to say "whichever it is, check out the latest
maintenance track", by doing:

  $ git checkout maint
  $ git branch --show-current
  maint-2.38

It is arguably better to say that we are on 'maint-2.38' rather than
on 'maint', and "git merge/pull" would record "into maint-2.38" and
not "into maint", so I think what we have is a good behaviour.

One thing that is slightly irritating, however, is that I do not
think there is a good way (other than "cat .git/HEAD") to learn that
you checked out 'maint' to get into that state.  Just like the output
of "git branch --show-current" shows above, "git symbolic-ref HEAD"
would report 'refs/heads/maint-2.38', bypassing the intermediate
symbolic ref at 'refs/heads/maint' that is pointed at by HEAD.

The internal resolve_ref() API already has the necessary support for
stopping after resolving a single level of a symbolic-ref, and we
can expose it by adding a "--[no-]recurse" option to the command.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-09 12:31:24 -07:00

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git-symbolic-ref(1)
===================
NAME
----
git-symbolic-ref - Read, modify and delete symbolic refs
SYNOPSIS
--------
[verse]
'git symbolic-ref' [-m <reason>] <name> <ref>
'git symbolic-ref' [-q] [--short] [--no-recurse] <name>
'git symbolic-ref' --delete [-q] <name>
DESCRIPTION
-----------
Given one argument, reads which branch head the given symbolic
ref refers to and outputs its path, relative to the `.git/`
directory. Typically you would give `HEAD` as the <name>
argument to see which branch your working tree is on.
Given two arguments, creates or updates a symbolic ref <name> to
point at the given branch <ref>.
Given `--delete` and an additional argument, deletes the given
symbolic ref.
A symbolic ref is a regular file that stores a string that
begins with `ref: refs/`. For example, your `.git/HEAD` is
a regular file whose contents is `ref: refs/heads/master`.
OPTIONS
-------
-d::
--delete::
Delete the symbolic ref <name>.
-q::
--quiet::
Do not issue an error message if the <name> is not a
symbolic ref but a detached HEAD; instead exit with
non-zero status silently.
--short::
When showing the value of <name> as a symbolic ref, try to shorten the
value, e.g. from `refs/heads/master` to `master`.
--recurse::
--no-recurse::
When showing the value of <name> as a symbolic ref, if
<name> refers to another symbolic ref, follow such a chain
of symbolic refs until the result no longer points at a
symbolic ref (`--recurse`, which is the default).
`--no-recurse` stops after dereferencing only a single level
of symbolic ref.
-m::
Update the reflog for <name> with <reason>. This is valid only
when creating or updating a symbolic ref.
NOTES
-----
In the past, `.git/HEAD` was a symbolic link pointing at
`refs/heads/master`. When we wanted to switch to another branch,
we did `ln -sf refs/heads/newbranch .git/HEAD`, and when we wanted
to find out which branch we are on, we did `readlink .git/HEAD`.
But symbolic links are not entirely portable, so they are now
deprecated and symbolic refs (as described above) are used by
default.
'git symbolic-ref' will exit with status 0 if the contents of the
symbolic ref were printed correctly, with status 1 if the requested
name is not a symbolic ref, or 128 if another error occurs.
GIT
---
Part of the linkgit:git[1] suite