diff --git a/builtin/checkout.c b/builtin/checkout.c
index e8110a9243..5af84a3118 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -661,7 +661,8 @@ static void update_refs_for_switch(const struct checkout_opts *opts,
describe_detached_head(_("HEAD is now at"), new->commit);
}
} else if (new->path) { /* Switch branches. */
- create_symref("HEAD", new->path, msg.buf);
+ if (create_symref("HEAD", new->path, msg.buf) < 0)
+ die("unable to update HEAD");
if (!opts->quiet) {
if (old->path && !strcmp(new->path, old->path)) {
if (opts->new_branch_force)
diff --git a/builtin/clone.c b/builtin/clone.c
index a0b3cd9e56..a7c8def8cb 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -636,9 +636,11 @@ static void update_remote_refs(const struct ref *refs,
struct strbuf head_ref = STRBUF_INIT;
strbuf_addstr(&head_ref, branch_top);
strbuf_addstr(&head_ref, "HEAD");
- create_symref(head_ref.buf,
- remote_head_points_at->peer_ref->name,
- msg);
+ if (create_symref(head_ref.buf,
+ remote_head_points_at->peer_ref->name,
+ msg) < 0)
+ die("unable to update %s", head_ref.buf);
+ strbuf_release(&head_ref);
}
}
@@ -648,7 +650,8 @@ static void update_head(const struct ref *our, const struct ref *remote,
const char *head;
if (our && skip_prefix(our->name, "refs/heads/", &head)) {
/* Local default branch link */
- create_symref("HEAD", our->name, NULL);
+ if (create_symref("HEAD", our->name, NULL) < 0)
+ die("unable to update HEAD");
if (!option_bare) {
update_ref(msg, "HEAD", our->old_oid.hash, NULL, 0,
UPDATE_REFS_DIE_ON_ERR);
diff --git a/refs.h b/refs.h
index 7a04077489..3c3da29bf0 100644
--- a/refs.h
+++ b/refs.h
@@ -292,7 +292,7 @@ extern char *shorten_unambiguous_ref(const char *refname, int strict);
/** rename ref, return 0 on success **/
extern int rename_ref(const char *oldref, const char *newref, const char *logmsg);
-extern int create_symref(const char *ref, const char *refs_heads_master, const char *logmsg);
+extern int create_symref(const char *refname, const char *target, const char *logmsg);
enum action_on_err {
UPDATE_REFS_MSG_ON_ERR,
diff --git a/refs/files-backend.c b/refs/files-backend.c
index c648b5e853..81c92b410e 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1840,12 +1840,17 @@ static int verify_lock(struct ref_lock *lock,
if (read_ref_full(lock->ref_name,
mustexist ? RESOLVE_REF_READING : 0,
lock->old_oid.hash, NULL)) {
- int save_errno = errno;
- strbuf_addf(err, "can't verify ref %s", lock->ref_name);
- errno = save_errno;
- return -1;
+ if (old_sha1) {
+ int save_errno = errno;
+ strbuf_addf(err, "can't verify ref %s", lock->ref_name);
+ errno = save_errno;
+ return -1;
+ } else {
+ hashclr(lock->old_oid.hash);
+ return 0;
+ }
}
- if (hashcmp(lock->old_oid.hash, old_sha1)) {
+ if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {
strbuf_addf(err, "ref %s is at %s but expected %s",
lock->ref_name,
sha1_to_hex(lock->old_oid.hash),
@@ -1882,7 +1887,8 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
const char *orig_refname = refname;
struct ref_lock *lock;
int last_errno = 0;
- int type, lflags;
+ int type;
+ int lflags = 0;
int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
int resolve_flags = 0;
int attempts_remaining = 3;
@@ -1893,10 +1899,11 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
if (mustexist)
resolve_flags |= RESOLVE_REF_READING;
- if (flags & REF_DELETING) {
+ if (flags & REF_DELETING)
resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
- if (flags & REF_NODEREF)
- resolve_flags |= RESOLVE_REF_NO_RECURSE;
+ if (flags & REF_NODEREF) {
+ resolve_flags |= RESOLVE_REF_NO_RECURSE;
+ lflags |= LOCK_NO_DEREF;
}
refname = resolve_ref_unsafe(refname, resolve_flags,
@@ -1932,6 +1939,10 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
goto error_return;
}
+
+ if (flags & REF_NODEREF)
+ refname = orig_refname;
+
/*
* If the ref did not exist and we are creating it, make sure
* there is no existing packed ref whose name begins with our
@@ -1947,11 +1958,6 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
lock->lk = xcalloc(1, sizeof(struct lock_file));
- lflags = 0;
- if (flags & REF_NODEREF) {
- refname = orig_refname;
- lflags |= LOCK_NO_DEREF;
- }
lock->ref_name = xstrdup(refname);
lock->orig_ref_name = xstrdup(orig_refname);
strbuf_git_path(&ref_file, "%s", refname);
@@ -1985,7 +1991,7 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
goto error_return;
}
}
- if (old_sha1 && verify_lock(lock, old_sha1, mustexist, err)) {
+ if (verify_lock(lock, old_sha1, mustexist, err)) {
last_errno = errno;
goto error_return;
}
@@ -2811,75 +2817,74 @@ static int commit_ref_update(struct ref_lock *lock,
return 0;
}
-int create_symref(const char *ref_target, const char *refs_heads_master,
- const char *logmsg)
+static int create_ref_symlink(struct ref_lock *lock, const char *target)
{
- char *lockpath = NULL;
- char ref[1000];
- int fd, len, written;
- char *git_HEAD = git_pathdup("%s", ref_target);
- unsigned char old_sha1[20], new_sha1[20];
- struct strbuf err = STRBUF_INIT;
-
- if (logmsg && read_ref(ref_target, old_sha1))
- hashclr(old_sha1);
-
- if (safe_create_leading_directories(git_HEAD) < 0)
- return error("unable to create directory for %s", git_HEAD);
-
+ int ret = -1;
#ifndef NO_SYMLINK_HEAD
- if (prefer_symlink_refs) {
- unlink(git_HEAD);
- if (!symlink(refs_heads_master, git_HEAD))
- goto done;
+ char *ref_path = get_locked_file_path(lock->lk);
+ unlink(ref_path);
+ ret = symlink(target, ref_path);
+ free(ref_path);
+
+ if (ret)
fprintf(stderr, "no symlink - falling back to symbolic ref\n");
- }
#endif
+ return ret;
+}
- len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
- if (sizeof(ref) <= len) {
- error("refname too long: %s", refs_heads_master);
- goto error_free_return;
- }
- lockpath = mkpathdup("%s.lock", git_HEAD);
- fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
- if (fd < 0) {
- error("Unable to open %s for writing", lockpath);
- goto error_free_return;
- }
- written = write_in_full(fd, ref, len);
- if (close(fd) != 0 || written != len) {
- error("Unable to write to %s", lockpath);
- goto error_unlink_return;
- }
- if (rename(lockpath, git_HEAD) < 0) {
- error("Unable to create %s", git_HEAD);
- goto error_unlink_return;
- }
- if (adjust_shared_perm(git_HEAD)) {
- error("Unable to fix permissions on %s", lockpath);
- error_unlink_return:
- unlink_or_warn(lockpath);
- error_free_return:
- free(lockpath);
- free(git_HEAD);
- return -1;
- }
- free(lockpath);
-
-#ifndef NO_SYMLINK_HEAD
- done:
-#endif
- if (logmsg && !read_ref(refs_heads_master, new_sha1) &&
- log_ref_write(ref_target, old_sha1, new_sha1, logmsg, 0, &err)) {
+static void update_symref_reflog(struct ref_lock *lock, const char *refname,
+ const char *target, const char *logmsg)
+{
+ struct strbuf err = STRBUF_INIT;
+ unsigned char new_sha1[20];
+ if (logmsg && !read_ref(target, new_sha1) &&
+ log_ref_write(refname, lock->old_oid.hash, new_sha1, logmsg, 0, &err)) {
error("%s", err.buf);
strbuf_release(&err);
}
+}
- free(git_HEAD);
+static int create_symref_locked(struct ref_lock *lock, const char *refname,
+ const char *target, const char *logmsg)
+{
+ if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
+ update_symref_reflog(lock, refname, target, logmsg);
+ return 0;
+ }
+
+ if (!fdopen_lock_file(lock->lk, "w"))
+ return error("unable to fdopen %s: %s",
+ lock->lk->tempfile.filename.buf, strerror(errno));
+
+ update_symref_reflog(lock, refname, target, logmsg);
+
+ /* no error check; commit_ref will check ferror */
+ fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
+ if (commit_ref(lock) < 0)
+ return error("unable to write symref for %s: %s", refname,
+ strerror(errno));
return 0;
}
+int create_symref(const char *refname, const char *target, const char *logmsg)
+{
+ struct strbuf err = STRBUF_INIT;
+ struct ref_lock *lock;
+ int ret;
+
+ lock = lock_ref_sha1_basic(refname, NULL, NULL, NULL, REF_NODEREF, NULL,
+ &err);
+ if (!lock) {
+ error("%s", err.buf);
+ strbuf_release(&err);
+ return -1;
+ }
+
+ ret = create_symref_locked(lock, refname, target, logmsg);
+ unlock_ref(lock);
+ return ret;
+}
+
int reflog_exists(const char *refname)
{
struct stat st;
diff --git a/t/t1401-symbolic-ref.sh b/t/t1401-symbolic-ref.sh
index ce8b4f4d0f..417eecc3af 100755
--- a/t/t1401-symbolic-ref.sh
+++ b/t/t1401-symbolic-ref.sh
@@ -114,4 +114,19 @@ test_expect_success 'symbolic-ref writes reflog entry' '
test_cmp expect actual
'
+test_expect_success 'symbolic-ref does not create ref d/f conflicts' '
+ git checkout -b df &&
+ test_commit df &&
+ test_must_fail git symbolic-ref refs/heads/df/conflict refs/heads/df &&
+ git pack-refs --all --prune &&
+ test_must_fail git symbolic-ref refs/heads/df/conflict refs/heads/df
+'
+
+test_expect_success 'symbolic-ref handles existing pointer to invalid name' '
+ head=$(git rev-parse HEAD) &&
+ git symbolic-ref HEAD refs/heads/outer &&
+ git update-ref refs/heads/outer/inner $head &&
+ git symbolic-ref HEAD refs/heads/unrelated
+'
+
test_done
diff --git a/t/t2011-checkout-invalid-head.sh b/t/t2011-checkout-invalid-head.sh
index 300f8bf25c..c5501b008c 100755
--- a/t/t2011-checkout-invalid-head.sh
+++ b/t/t2011-checkout-invalid-head.sh
@@ -19,4 +19,43 @@ test_expect_success 'checkout master from invalid HEAD' '
git checkout master --
'
+test_expect_success 'checkout notices failure to lock HEAD' '
+ test_when_finished "rm -f .git/HEAD.lock" &&
+ >.git/HEAD.lock &&
+ test_must_fail git checkout -b other
+'
+
+test_expect_success 'create ref directory/file conflict scenario' '
+ git update-ref refs/heads/outer/inner master &&
+
+ # do not rely on symbolic-ref to get a known state,
+ # as it may use the same code we are testing
+ reset_to_df () {
+ echo "ref: refs/heads/outer" >.git/HEAD
+ }
+'
+
+test_expect_success 'checkout away from d/f HEAD (unpacked, to branch)' '
+ reset_to_df &&
+ git checkout master
+'
+
+test_expect_success 'checkout away from d/f HEAD (unpacked, to detached)' '
+ reset_to_df &&
+ git checkout --detach master
+'
+
+test_expect_success 'pack refs' '
+ git pack-refs --all --prune
+'
+
+test_expect_success 'checkout away from d/f HEAD (packed, to branch)' '
+ reset_to_df &&
+ git checkout master
+'
+
+test_expect_success 'checkout away from d/f HEAD (packed, to detached)' '
+ reset_to_df &&
+ git checkout --detach master
+'
test_done