git/builtin/symbolic-ref.c
Junio C Hamano 12cfa792b8 symbolic-ref -d: do not allow removal of HEAD
If you delete the symbolic-ref HEAD from a repository, Git no longer
considers the repository valid, and even "git symbolic-ref HEAD
refs/heads/master" would not be able to recover from that state
(although "git init" can, but that is a sure sign that you are
talking about a "broken" repository).

In the spirit similar to afe5d3d5 ("symbolic ref: refuse non-ref
targets in HEAD", 2009-01-29), forbid removal of HEAD to avoid
corrupting a repository.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-02 09:01:38 -07:00

79 lines
2.0 KiB
C

#include "builtin.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] <name>"),
NULL
};
static int check_symref(const char *HEAD, int quiet, int shorten, int print)
{
unsigned char sha1[20];
int flag;
const char *refname = resolve_ref_unsafe(HEAD, 0, sha1, &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) {
if (shorten)
refname = shorten_unambiguous_ref(refname, 0);
puts(refname);
}
return 0;
}
int cmd_symbolic_ref(int argc, const char **argv, const char *prefix)
{
int quiet = 0, delete = 0, shorten = 0, 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_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);
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(argv[0], NULL, REF_NODEREF);
}
switch (argc) {
case 1:
ret = check_symref(argv[0], quiet, shorten, 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;
}