When we parse "git checkout $NAME", we try to interpret
$NAME as a local branch-name. If it is, then we point HEAD
to that branch. Otherwise, we detach the HEAD at whatever
commit $NAME points to.
We do the interpretation by calling strbuf_branchname(), and
then blindly sticking "refs/heads/" on the front. This leads
to nonsense results when expansions like "@{upstream}" or
"@" point to something besides a local branch. We end up
with a local branch name like "refs/heads/origin/master" or
"refs/heads/HEAD".
Normally this has no user-visible effect because those
branches don't exist, and so we fallback to feeding the
result to get_sha1(), which resolves them correctly.
But as the new test in t3204 shows, there are corner cases
where the effect is observable, and we check out the wrong
local branch rather than detaching to the correct one.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This function asks strbuf_branchname() to expand any @-marks
in the branchname, and then we blindly stick refs/heads/ in
front of the result. This is obviously nonsense if the
expansion is "HEAD" or a ref in refs/remotes/.
The most obvious end-user effect is that creating or
renaming a branch with an expansion may have confusing
results (e.g., creating refs/heads/origin/master from
"@{upstream}" when the operation should be disallowed).
We can fix this by telling strbuf_branchname() that we are
only interested in local expansions. Any unexpanded bits are
then fed to check_ref_format(), which either disallows them
(in the case of "@{upstream}") or lets them through
("refs/heads/@" is technically valid, if a bit silly).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We use strbuf_branchname() to expand the branch name from
the command line, so you can delete the branch given by
@{-1}, for example. However, we allow other nonsense like
"@", and we do not respect our "-r" flag (so we may end up
deleting an oddly-named local ref instead of a remote one).
We can fix this by passing the appropriate "allowed" flag to
strbuf_branchname().
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
git-branch feeds the branch names from the command line to
strbuf_branchname(), but we do not yet tell that function
which kinds of expansions should be allowed. Let's create a
set of tests that cover both the allowed and disallowed
cases.
That shows off some breakages where we currently create or
delete the wrong ref (and will make sure that we do not
break any cases that _should_ be working when we do add more
restrictions).
Note that we check branch creation and deletion, but do not
bother with renames. Those follow the same code path as
creation.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
