Re: BUG when trying to delete symbolic refs
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Oct 16, 2012, 16:09 UTC
- Message-ID
- <7vr4oytn4q.fsf@alter.siamese.dyndns.org>
- In-Reply-To
- <507D315E.8040101@lsrfire.ath.cx>
René Scharfe <rene.scharfe@lsrfire.ath.cx> writes:
Show 28 quoted lines
> Am 15.10.2012 10:50, schrieb Johan Herland: >> Basically, there is a "master" branch, and an "alias" symref to >> "master". When we naively try to delete the symref with "git branch -d >> alias", it ends up: >> >> - NOT deleting the "alias" symref >> - DELETING the "master" loose ref >> - NOT deleting the "master" packed ref >> >> So, from the user perspective, "git branch -d alias" ends up resetting >> "master" (and "alias") back to the last time we happened to run "git >> gc". Needless to say, this is not quite what we had in mind... >> >> AFAICS, there may be three possible "acceptable" outcomes when we run >> "git branch -d alias" in the above scenario: >> >> A. The symbolic ref is deleted. This is obviously what we expected... > > Below is a patch to do that. > >> B. The command fails because "alias" is a symref. This would be >> understandable if we don't want to teach "branch -d" about symrefs. >> But then, the error message should ideally explain which command we >> should use to remove the symref. > > Renaming of symrefs with branch -m is disallowed because it's more > complicated than it looks at first; this was discussed here: > http://thread.gmane.org/gmane.comp.version-control.git/98825/focus=99206
Thanks for a reminder.
> I can't imagine why deletion should be prohibited as well, though.
I am not sure if it is a good idea to let "update-ref -d" work on a symref, with or without --no-deref. There are cases where you want to remove the pointer ("symbolic-ref -d" is there for that), and there are cases where you want to remove the underlying ref (but of course you can "update-ref -d" the underlying ref yourself). If "update-ref -d" refused to work on a symref, we do not have to worry about the confusion "which one is removed---the pointer, or the pointee?"
> But I wonder why most delete_ref() calls in the code actually don't use > the flag REF_NODEREF, thus deleting symref targets instead of the > symrefs themselves. I may be missing something important here.
I suspect that is primarily because using a symref to represent anything other than $GIT_DIR/HEAD and $GIT_DIR/refs/remotes/*/HEAD is outside the normally supported use case and in the "may happen to work" territory.
Having said all that, I think your patch is going in the right direction. If somebody had a symbolic ref in refs/heads/, the removal should remove it, not the pointee, which may not even exist. Does "branch -d sym" work correctly with your patch when refs/heads/sym is pointing at something that does not exist?
Show 39 quoted lines
> ---
> builtin/branch.c | 2 +-
> t/t3200-branch.sh | 10 ++++++++++
> 2 files changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/builtin/branch.c b/builtin/branch.c
> index ffd2684..31af114 100644
> --- a/builtin/branch.c
> +++ b/builtin/branch.c
> @@ -221,7 +221,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
> continue;
> }
>
> - if (delete_ref(name, sha1, 0)) {
> + if (delete_ref(name, sha1, REF_NODEREF)) {
> error(remote_branch
> ? _("Error deleting remote branch '%s'")
> : _("Error deleting branch '%s'"),
> diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
> index 79c8d01..4b73406 100755
> --- a/t/t3200-branch.sh
> +++ b/t/t3200-branch.sh
> @@ -262,6 +262,16 @@ test_expect_success 'config information was renamed, too' \
> "test $(git config branch.s.dummy) = Hello &&
> test_must_fail git config branch.s/s/dummy"
>
> +test_expect_success 'deleting a symref' '
> + git branch target &&
> + git symbolic-ref refs/heads/symlink refs/heads/target &&
> +
> + git branch -d symlink &&
> +
> + test_path_is_file .git/refs/heads/target &&
> + test_path_is_missing .git/refs/heads/symlink
> +'
> +
> test_expect_success 'renaming a symref is not allowed' \
> '
> git symbolic-ref refs/heads/master2 refs/heads/master &&