[PATCH 9/9] refs.c: make @ a pseudo-ref alias to HEAD
First, make sure that check_refname_format() rejects the a refname beginning with a '@'. Add a test to t1400 (update-ref) demonstrating that update-ref forbids the user from updating a ref named "@".
Now, resolve_ref_unsafe() is built to resolve any refs that have a corresponding file inside $GITDIR. Our "@" ref is a special pseudo-ref and does not have a filesystem counterpart. So, hard-interpret "@" as "HEAD" and resolve .git/HEAD as usual. This means that we can drop the 'git symbolic-ref @ HEAD' line in t1508 (at-combinations), and everything will continue working as usual.
If the user does manage to create a '.git/@' unsafely (via symbolic-ref or otherwise), it will be ignored.
In practice, this means that you will now be able to do:
$ git show @~1
$ git log @^2Advertise these features in the tests and documentation.
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
---
Documentation/git-check-ref-format.txt | 2 ++
Documentation/revisions.txt | 8 ++++++--
refs.c | 12 ++++++++++--
t/t1400-update-ref.sh | 3 +++
t/t1508-at-combinations.sh | 4 +---
5 files changed, 22 insertions(+), 7 deletions(-)
Show changes to 5 files +22 −7
Documentation/git-check-ref-format.txt, Documentation/revisions.txt, refs.c, t/t1400-update-ref.sh, t/t1508-at-combinations.sh
diff --git a/Documentation/git-check-ref-format.txt b/Documentation/git-check-ref-format.txt
index ec1739a..3de9adc 100644
--- a/Documentation/git-check-ref-format.txt
+++ b/Documentation/git-check-ref-format.txt
@@ -52,6 +52,8 @@ Git imposes the following rules on how references are named:
. They cannot end with a dot `.`.
+. They cannot be the single character `@`.
+
. They cannot contain a sequence `@{`.
. They cannot contain a `\`.
diff --git a/Documentation/revisions.txt b/Documentation/revisions.txt
index d477b3f..02bfc90 100644
--- a/Documentation/revisions.txt
+++ b/Documentation/revisions.txt
@@ -27,6 +27,10 @@ blobs contained in a commit.
When ambiguous, a '<refname>' is disambiguated by taking the
first match in the following rules:
+ . '@' is a synonym for 'HEAD'. An '@' followed by '\{' has no
+ relationship to this and means something entirely different (see
+ below).
+
. If '$GIT_DIR/<refname>' exists, that is what you mean (this is usually
useful only for 'HEAD', 'FETCH_HEAD', 'ORIG_HEAD', 'MERGE_HEAD'
and 'CHERRY_PICK_HEAD');
@@ -93,7 +97,7 @@ some output processing may assume ref names in UTF-8.
refers to the branch that the branch specified by branchname is set to build on
top of. A missing branchname defaults to the current one.
-'<rev>{caret}', e.g. 'HEAD{caret}, v1.5.1{caret}0'::
+'<rev>{caret}', e.g. '@{caret}2', 'HEAD{caret}', 'v1.5.1{caret}0'::
A suffix '{caret}' to a revision parameter means the first parent of
that commit object. '{caret}<n>' means the <n>th parent (i.e.
'<rev>{caret}'
@@ -101,7 +105,7 @@ some output processing may assume ref names in UTF-8.
'<rev>{caret}0' means the commit itself and is used when '<rev>' is the
object name of a tag object that refers to a commit object.
-'<rev>{tilde}<n>', e.g. 'master{tilde}3'::
+'<rev>{tilde}<n>', e.g. '@{tilde}1', 'master{tilde}3'::
A suffix '{tilde}<n>' to a revision parameter means the commit
object that is the <n>th generation ancestor of the named
commit object, following only the first parents. I.e. '<rev>{tilde}3' is
diff --git a/refs.c b/refs.c
index de2d8eb..6a75f77 100644
--- a/refs.c
+++ b/refs.c
@@ -72,6 +72,9 @@ int check_refname_format(const char *refname, int flags)
{
int component_len, component_count = 0;
+ if (!strcmp(refname, "@"))
+ return -1;
+
while (1) {
/* We are at the start of a path component. */
component_len = check_refname_component(refname, flags);
@@ -1093,8 +1096,13 @@ const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int rea
if (flag)
*flag = 0;
- if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
- return NULL;
+ if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL) < 0) {
+ /* Handle the pseudo-ref @ */
+ if (!strcmp(refname, "@"))
+ refname = "HEAD";
+ else
+ return NULL;
+ }
for (;;) {
char path[PATH_MAX];
diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index e415ee0..ee93979 100755
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -127,6 +127,9 @@ test_expect_success '(not) change HEAD with wrong SHA1' "
test_expect_success "(not) changed .git/$m" "
! test $B"' = $(cat .git/'"$m"')
'
+test_expect_success 'disallow creating a ref with name @' '
+ test_must_fail git update-ref @ HEAD
+'
rm -f .git/$m
: a repository with working tree always has reflog these days...
diff --git a/t/t1508-at-combinations.sh b/t/t1508-at-combinations.sh
index 6a69f9e..c50c3f7 100755
--- a/t/t1508-at-combinations.sh
+++ b/t/t1508-at-combinations.sh
@@ -65,9 +65,7 @@ check "H@{1}" commit new-one
check "H@{now}" commit new-two
check "H@{u}" refs/heads/upstream-branch
-# To make sure that the @-parser isn't buggy, check things with the
-# symbolic-ref @
-git symbolic-ref @ HEAD
+# Check everything with pseudo-ref @
check "@@{1}" commit new-one
check "@@{now}" commit new-two
check "@@{u}" refs/heads/upstream-branch
--
1.8.3.rc0.40.g09a0447
Ramkumar Ramachandra
