Re: Should "git symbolic-ref -d HEAD" be forbidden?
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Sep 1, 2016, 22:31 UTC
- Message-ID
- <xmqq8tvbuu9r.fsf@gitster.mtv.corp.google.com>
- In-Reply-To
- <20160901211907.iivokwu3yjuxz3qf@sigill.intra.peff.net>
Jeff King <peff@peff.net> writes:
Show 21 quoted lines
> On Thu, Sep 01, 2016 at 02:08:08PM -0700, Junio C Hamano wrote: > >> I think we should. >> >> t1401 expects to be able to, but if you really do it: >> >> $ cd /tmp >> $ git init throwaway >> $ cd throwaway >> $ git symbolic-ref -d HEAD >> >> the setup machinery considers that you are no longer in a working >> tree that is controlled by a repository at .git/ because .git/ is >> no longer a valid repository, so you cannot even do >> >> $ git symbolic-ref HEAD refs/heads/master >> >> to recover. > > Yes, I think we should, too. The same reasoning from afe5d3d (symbolic > ref: refuse non-ref targets in HEAD, 2009-01-29) applies.
-- >8 -- Subject: symbolic-ref -d: do not allow removal of HEAD
If you delete the symbolic-ref HEAD from a repository, Git no longer considers it valid, and even "git symbolic-ref HEAD refs/heads/master" would not be able to recover from that state.
In the spirit similar to afe5d3d5 ("symbolic ref: refuse non-ref targets in HEAD", 2009-01-29), forbid removal of HEAD.
Signed-off-by: Junio C Hamano <gitster@pobox.com> ---
I decided against it for now for no good reason, other than I am a bit superstitious, but it may be a good idea to move these safety checks to delete_ref() and create_symref() in the longer term.
builtin/symbolic-ref.c | 2 ++ t/t1401-symbolic-ref.sh | 19 ++++++++++++------- 2 files changed, 14 insertions(+), 7 deletions(-)
diff --git a/builtin/symbolic-ref.c b/builtin/symbolic-ref.c index 9c29a64..96eed94 100644 --- a/builtin/symbolic-ref.c +++ b/builtin/symbolic-ref.c @@ -56,6 +56,8 @@ int cmd_symbolic_ref(int argc, const char **argv, const char *prefix) 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); } diff --git a/t/t1401-symbolic-ref.sh b/t/t1401-symbolic-ref.sh index ca3fa40..5c30f94 100755 --- a/t/t1401-symbolic-ref.sh +++ b/t/t1401-symbolic-ref.sh @@ -33,18 +33,23 @@ test_expect_success 'symbolic-ref refuses bare sha1' ' ' reset_to_sane -test_expect_success 'symbolic-ref deletes HEAD' ' - git symbolic-ref -d HEAD && +test_expect_success 'HEAD cannot be removed' ' + test_must_fail git symbolic-ref -d HEAD +' + +test_expect_success 'symbolic-ref can be deleted' ' + git symbolic-ref NOTHEAD refs/heads/foo && + git symbolic-ref -d NOTHEAD && test_path_is_file .git/refs/heads/foo && - test_path_is_missing .git/HEAD + test_path_is_missing .git/NOTHEAD ' reset_to_sane -test_expect_success 'symbolic-ref deletes dangling HEAD' ' - git symbolic-ref HEAD refs/heads/missing && - git symbolic-ref -d HEAD && +test_expect_success 'symbolic-ref can delete dangling symref' ' + git symbolic-ref NOTHEAD refs/heads/missing && + git symbolic-ref -d NOTHEAD && test_path_is_missing .git/refs/heads/missing && - test_path_is_missing .git/HEAD + test_path_is_missing .git/NOTHEAD ' reset_to_sane