[PATCH v2 3/3] read_loose_refs(): treat NULL_SHA1 loose references as broken
- From
Michael Haggerty <mhagger@alum.mit.edu>
- Date
- Jun 2, 2015, 15:57 UTC
- Message-ID
- <1433260647-18181-4-git-send-email-mhagger@alum.mit.edu>
- In-Reply-To
- <1433260647-18181-1-git-send-email-mhagger@alum.mit.edu>
NULL_SHA1 is never a valid value for a reference. If a loose reference has that value, mark it as broken.
Why check NULL_SHA1 and not the nearly 2^160 other SHA-1s that are also invalid in a given repository? Because (a) it is cheap to test for NULL_SHA1, and (b) NULL_SHA1 is often used as a "SHA-1 is invalid" value inside of Git client source code (not only ours!), and accidentally writing it to a loose reference file would be an easy mistake to make.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> --- refs.c | 7 +++++++ t/t6301-for-each-ref-errors.sh | 2 +- 2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/refs.c b/refs.c index 47e4e53..c28fde1 100644 --- a/refs.c +++ b/refs.c @@ -1321,6 +1321,13 @@ static void read_loose_refs(const char *dirname, struct ref_dir *dir) hashclr(sha1); flag |= REF_ISBROKEN; } + + if (!(flag & REF_ISBROKEN) && is_null_sha1(sha1)) { + /* NULL_SHA1 is never a valid reference value. */ + hashclr(sha1); + flag |= REF_ISBROKEN; + } + if (check_refname_format(refname.buf, REFNAME_ALLOW_ONELEVEL)) { hashclr(sha1); diff --git a/t/t6301-for-each-ref-errors.sh b/t/t6301-for-each-ref-errors.sh index 72d2397..cdb67a0 100755 --- a/t/t6301-for-each-ref-errors.sh +++ b/t/t6301-for-each-ref-errors.sh @@ -24,7 +24,7 @@ test_expect_success 'Broken refs are reported correctly' ' test_cmp broken-err err ' -test_expect_failure 'NULL_SHA1 refs are reported correctly' ' +test_expect_success 'NULL_SHA1 refs are reported correctly' ' r=refs/heads/zeros && echo $ZEROS >.git/$r && test_when_finished "rm -f .git/$r" &&
-- 2.1.4