We hit a segfault when trying to open a bundle via `git bundle
list-heads` when running outside of a repository. This is caused by
c8aed5e8da (repository: stop setting SHA1 as the default object hash,
2024-05-07), which stopped setting the default object hash so that
`the_hash_algo` is a `NULL` pointer when running outside of any repo.
This is only a symptom of a deeper issue though. Bundles default to the
SHA1 object format unless they advertise an "@object-format=" header.
Consequently, it has been wrong in the first place to use the object
format used by the current repository when parsing bundles. The
consequence is that trying to open a bundle that uses a different object
hash than the current repository will fail:
$ git bundle list-heads sha1.bundle
error: unrecognized header: ee4b540943284700a32591ad09f7e15bdeb2a10c HEAD (45)
Fix the bug by defaulting to the SHA1 object hash. We already handle the
"@object-format=" header as expected, so we don't need to adapt this
part.
Helped-by: brian m. carlson <sandals@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Patrick Steinhardt <ps@xxxxxx>
---
bundle.c | 7 ++++++-
t/t6020-bundle-misc.sh | 25 +++++++++++++++++++++++++
2 files changed, 31 insertions(+), 1 deletion(-)
diff --git a/bundle.c b/bundle.c
index ce164c37bc..b0a8a925cb 100644
--- a/bundle.c
+++ b/bundle.c
@@ -89,7 +89,12 @@ int read_bundle_header_fd(int fd, struct bundle_header *header,
goto abort;
}
- header->hash_algo = the_hash_algo;
+ /*
+ * The default hash format for bundles is SHA1, unless told otherwise
+ * by an "object-format=" capability, which is being handled in
+ * `parse_capability()`.
+ */
+ header->hash_algo = &hash_algos[GIT_HASH_SHA1];
/* The bundle header ends with an empty line */
while (!strbuf_getwholeline_fd(&buf, fd, '\n') &&
diff --git a/t/t6020-bundle-misc.sh b/t/t6020-bundle-misc.sh
index 703434b472..34b5cd62c2 100755
--- a/t/t6020-bundle-misc.sh
+++ b/t/t6020-bundle-misc.sh
@@ -659,4 +659,29 @@ test_expect_success 'unbundle outside of a repository' '
test_cmp expect err
'
+test_expect_success 'list-heads outside of a repository' '
+ git bundle create some.bundle HEAD &&
+ cat >expect <<-EOF &&
+ $(git rev-parse HEAD) HEAD
+ EOF
+ nongit git bundle list-heads "$(pwd)/some.bundle" >actual &&
+ test_cmp expect actual
+'
+
+for hash in sha1 sha256
+do
+ test_expect_success "list-heads with bundle using $hash" '
+ test_when_finished "rm -rf hash" &&
+ git init --object-format=$hash hash &&
+ test_commit -C hash initial &&
+ git -C hash bundle create hash.bundle HEAD &&
+
+ cat >expect <<-EOF &&
+ $(git -C hash rev-parse HEAD) HEAD
+ EOF
+ git bundle list-heads hash/hash.bundle >actual &&
+ test_cmp expect actual
+ '
+done
+
test_done
--
2.46.0.46.g406f326d27.dirty
