[PATCH v2 1/2] branch: forbid refs/heads/HEAD

From

Kaartic Sivaraam <kaartic.sivaraam@gmail.com>

Date

Nov 14, 2017, 11:42 UTC

Message-ID

<20171114114259.8937-1-kaartic.sivaraam@gmail.com>

In-Reply-To

<20171013051132.3973-1-gitster@pobox.com>

From: Junio C Hamano <gitster@pobox.com>

Use it to also reject "HEAD" as a branch name.

Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Kaartic Sivaraam <kaartic.sivaraam@gmail.com>
---
  Changes in v2:

  * Fixed the issue of .git/HEAD being renamed when trying to do,

      $ git branch -m HEAD head

   This also allows to rename a branch named HEAD that was created by accident.

   cf. <1509209933.2256.4.camel@gmail.com>

  * Added a test to ensure that it is possible to rename a branch named HEAD.

 sha1_name.c             |  8 +++++++-
 t/t1430-bad-ref-name.sh | 29 +++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/sha1_name.c b/sha1_name.c
index 9a2d5caf3..657a060cb 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -1438,9 +1438,15 @@ int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
 		strbuf_branchname(sb, name, INTERPRET_BRANCH_LOCAL);
 	else
 		strbuf_addstr(sb, name);
-	if (name[0] == '-')
+	if (*name == '-')
 		return -1;
+
 	strbuf_splice(sb, 0, 0, "refs/heads/", 11);
+
+	/* HEAD is not to be used as a branch name */
+	if(!strcmp(sb->buf, "refs/heads/HEAD"))
+		return -1;
+
 	return check_refname_format(sb->buf, 0);
 }
 
diff --git a/t/t1430-bad-ref-name.sh b/t/t1430-bad-ref-name.sh
index e88349c8a..421e80a7a 100755
--- a/t/t1430-bad-ref-name.sh
+++ b/t/t1430-bad-ref-name.sh
@@ -331,4 +331,33 @@ test_expect_success 'update-ref --stdin -z fails delete with bad ref name' '
 	grep "fatal: invalid ref format: ~a" err
 '
 
+test_expect_success 'branch rejects HEAD as a branch name' '
+	test_must_fail git branch HEAD HEAD^ &&
+	test_must_fail git show-ref refs/heads/HEAD
+'
+
+test_expect_success 'checkout -b rejects HEAD as a branch name' '
+	test_must_fail git checkout -B HEAD HEAD^ &&
+	test_must_fail git show-ref refs/heads/HEAD
+'
+
+test_expect_success 'update-ref can operate on refs/heads/HEAD' '
+	git update-ref refs/heads/HEAD HEAD^ &&
+	git show-ref refs/heads/HEAD &&
+	git update-ref -d refs/heads/HEAD &&
+	test_must_fail git show-ref refs/heads/HEAD
+'
+
+test_expect_success 'branch -d can remove refs/heads/HEAD' '
+	git update-ref refs/heads/HEAD HEAD^ &&
+	git branch -d HEAD &&
+	test_must_fail git show-ref refs/heads/HEAD
+'
+
+test_expect_success 'branch -m can rename refs/heads/HEAD' '
+	git update-ref refs/heads/HEAD HEAD^ &&
+	git branch -m HEAD head &&
+	test_must_fail git show-ref refs/heads/HEAD
+'
+
 test_done

-- 
2.15.0.rc2.397.geff0134c7.dirty