git/builtin/symbolic-ref.c
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

85 lines
2.3 KiB
C

#include "builtin.h"
#include "config.h"
#include "cache.h"
#include "refs.h"
#include "parse-options.h"
static const char * const git_symbolic_ref_usage[] = {
N_("git symbolic-ref [<options>] <name> [<ref>]"),
N_("git symbolic-ref -d [-q] [--no-recurse] <name>"),
NULL
};
static int check_symref(const char *HEAD, int quiet, int shorten, int recurse, int print)
{
int resolve_flags, flag;
const char *refname;
resolve_flags = (recurse ? 0 : RESOLVE_REF_NO_RECURSE);
refname = resolve_ref_unsafe(HEAD, resolve_flags, NULL, &flag);
if (!refname)
die("No such ref: %s", HEAD);
else if (!(flag & REF_ISSYMREF)) {
if (!quiet)
die("ref %s is not a symbolic ref", HEAD);
else
return 1;
}
if (print) {
char *to_free = NULL;
if (shorten)
refname = to_free = shorten_unambiguous_ref(refname, 0);
puts(refname);
free(to_free);
}
return 0;
}
int cmd_symbolic_ref(int argc, const char **argv, const char *prefix)
{
int quiet = 0, delete = 0, shorten = 0, recurse = 1, ret = 0;
const char *msg = NULL;
struct option options[] = {
OPT__QUIET(&quiet,
N_("suppress error message for non-symbolic (detached) refs")),
OPT_BOOL('d', "delete", &delete, N_("delete symbolic ref")),
OPT_BOOL(0, "short", &shorten, N_("shorten ref output")),
OPT_BOOL(0, "recurse", &recurse, N_("recursively dereference (default)")),
OPT_STRING('m', NULL, &msg, N_("reason"), N_("reason of the update")),
OPT_END(),
};
git_config(git_default_config, NULL);
argc = parse_options(argc, argv, prefix, options,
git_symbolic_ref_usage, 0);
if (msg && !*msg)
die("Refusing to perform update with empty message");
if (delete) {
if (argc != 1)
usage_with_options(git_symbolic_ref_usage, options);
ret = check_symref(argv[0], 1, 0, 0, 0);
if (ret)
die("Cannot delete %s, not a symbolic ref", argv[0]);
if (!strcmp(argv[0], "HEAD"))
die("deleting '%s' is not allowed", argv[0]);
return delete_ref(NULL, argv[0], NULL, REF_NO_DEREF);
}
switch (argc) {
case 1:
ret = check_symref(argv[0], quiet, shorten, recurse, 1);
break;
case 2:
if (!strcmp(argv[0], "HEAD") &&
!starts_with(argv[1], "refs/"))
die("Refusing to point HEAD outside of refs/");
ret = !!create_symref(argv[0], argv[1], msg);
break;
default:
usage_with_options(git_symbolic_ref_usage, options);
}
return ret;
}