Hi,
A bug was filed in the Fedora/Red Hat bugzilla today for the
git 2.35.0 rc (rc1, but it's the same in rc2). Petr (Cc'd),
ran the following
git clone https://github.com/psss/fmf /tmp/fmf
cd /tmp/fmf
cp .git/refs/remotes/origin/HEAD .git/refs/heads/__DEFAULT__
git checkout -f __DEFAULT__
git checkout -f __DEFAULT__
The second git checkout call runs into the BUG() call added
in 9081a421a6 (checkout: fix "branch info" memory leaks,
2021-11-16):
BUG: builtin/checkout.c:1098: should be able to skip
past 'refs/heads/' in 'refs/remotes/origin/master'!
Aborted (core dumped)
This worked in 2.34.1, so it's new to 2.35.0. Should this
work or does the manual copy to setup a branch fall into a
new category of "don't do that"?
(It's novel to get a bug report from rc testing of a distro
build -- that doesn't happen often.)
--
Todd
Fix a regression in my 9081a421a6d (checkout: fix "branch info" memory
leaks, 2021-11-16) where I'd assumed that the old_branch_info.path
would have to start with refs/heads/*, but as has been reported[1]
that's not the case.
As a test case[2] to reproduce this shows the second "git checkout"
here runs into the BUG() in the pre-image. The test being added is
amended from[2] and will pass both with this change, and before
9081a421a6. I.e. our behavior now is again the same as before that
commit.
1. https://bugzilla.redhat.com/show_bug.cgi?id=2042920
2. https://lore.kernel.org/git/YemTGQZ97vAPUPY0@pobox.com/
Reported-by: Petr Šplíchal <redacted>
Reported-by: Todd Zullinger <redacted>
Signed-off-by: Ævar Arnfjörð Bjarmason <redacted>
---
On Thu, Jan 20 2022, Todd Zullinger wrote:
Hi,
A bug was filed in the Fedora/Red Hat bugzilla today for the
git 2.35.0 rc (rc1, but it's the same in rc2). Petr (Cc'd),
ran the following
git clone https://github.com/psss/fmf /tmp/fmf
cd /tmp/fmf
cp .git/refs/remotes/origin/HEAD .git/refs/heads/__DEFAULT__
git checkout -f __DEFAULT__
git checkout -f __DEFAULT__
The second git checkout call runs into the BUG() call added
in 9081a421a6 (checkout: fix "branch info" memory leaks,
2021-11-16):
BUG: builtin/checkout.c:1098: should be able to skip
past 'refs/heads/' in 'refs/remotes/origin/master'!
Aborted (core dumped)
This worked in 2.34.1, so it's new to 2.35.0. Should this
work or does the manual copy to setup a branch fall into a
new category of "don't do that"?
(It's novel to get a bug report from rc testing of a distro
build -- that doesn't happen often.)
Thanks to both you and Petr for the report and easy to reproduce case,
and sorry about causing it.
In retrospec it's a rather obvious thinko. Here's a minimal fix for
it, along with a derived test case that I made more exhaustive to
check the state of the repo before, after, and in-between the two "git
checkout" commands. As noted it'll also pass with 9081a421a6d
reverted, showing that our behavior is the same as before that commit.
builtin/checkout.c | 11 ++++-------
t/t2018-checkout-branch.sh | 33 +++++++++++++++++++++++++++++++++
2 files changed, 37 insertions(+), 7 deletions(-)
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 6a5dd2a2a22..52a47ef40e1 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -1090,13 +1090,10 @@ static int switch_branches(const struct checkout_opts *opts,
FREE_AND_NULL(old_branch_info.path);
if (old_branch_info.path) {
- const char *const prefix = "refs/heads/";
- const char *p;
- if (skip_prefix(old_branch_info.path, prefix, &p))
- old_branch_info.name = xstrdup(p);
- else
- BUG("should be able to skip past '%s' in '%s'!",
- prefix, old_branch_info.path);
+ const char *p = old_branch_info.path;
+
+ skip_prefix(old_branch_info.path, "refs/heads/", &p);
+ old_branch_info.name = xstrdup(p);
}
if (opts->new_orphan_branch && opts->orphan_from_empty_tree) {diff --git a/t/t2018-checkout-branch.sh b/t/t2018-checkout-branch.sh
index 3e93506c045..82df9b8bf64 100755
--- a/t/t2018-checkout-branch.sh
+++ b/t/t2018-checkout-branch.sh
@@ -85,6 +85,39 @@ test_expect_success 'setup' '
git branch -m branch1
'
+test_expect_success REFFILES 'checkout a branch without refs/heads/* prefix' '
+ git clone --no-tags . repo-odd-prefix &&
+ (
+ cd repo-odd-prefix &&
+
+ cp .git/refs/remotes/origin/HEAD .git/refs/heads/a-branch &&
+
+ echo branch1 >expect.ref &&
+ git rev-parse --abbrev-ref HEAD >actual.ref &&
+ test_cmp expect.ref actual.ref &&
+
+ git checkout -f a-branch &&
+
+ echo origin/branch1 >expect.ref &&
+ git rev-parse --abbrev-ref HEAD >actual.ref &&
+ test_cmp expect.ref actual.ref &&
+
+ git checkout -f a-branch &&
+
+ cat >expect <<-EOF &&
+ $(git rev-parse HEAD) commit refs/heads/a-branch
+ $(git rev-parse HEAD) commit refs/heads/branch1
+ $(git rev-parse HEAD) commit refs/remotes/origin/HEAD
+ $(git rev-parse HEAD) commit refs/remotes/origin/branch1
+ EOF
+ git for-each-ref >actual &&
+ test_cmp expect actual &&
+
+ git rev-parse --abbrev-ref HEAD >actual &&
+ test_cmp expect.ref actual.ref
+ )
+'
+
test_expect_success 'checkout -b to a new branch, set to HEAD' '
test_when_finished "
git checkout branch1 &&
--
2.35.0.rc1.864.g57621b115b6
Hi,
Ævar Arnfjörð Bjarmason wrote:
Thanks to both you and Petr for the report and easy to reproduce case,
and sorry about causing it.
In retrospec it's a rather obvious thinko. Here's a minimal fix for
it, along with a derived test case that I made more exhaustive to
check the state of the repo before, after, and in-between the two "git
checkout" commands. As noted it'll also pass with 9081a421a6d
reverted, showing that our behavior is the same as before that commit.
I can confirm the new test succeeds and the case which Petr
reported works as it did in previous releases.
Many thanks for the quick fix and more extensive tests Ævar!
--
Todd