Force writing ref if it doesn't exist.

Normally we try to skip writing a ref if its value hasn't changed
but in the special case that the ref doesn't exist but the new
value is going to be 0{40} then force writing the ref anyway.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/refs.c b/refs.c
index 9d37a02..31cf276 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -288,6 +288,7 @@ static struct ref_lock* lock_ref_sha1_basic(const char *path,
        const unsigned char *old_sha1, int mustexist)
 {
        struct ref_lock *lock;
+       struct stat st;
 
        lock = xcalloc(1, sizeof(struct ref_lock));
        lock->lock_fd = -1;
@@ -303,6 +304,7 @@ static struct ref_lock* lock_ref_sha1_basic(const char *path,
        lock->ref_file = strdup(path);
        lock->lock_file = strdup(mkpath("%s.lock", lock->ref_file));
        lock->log_file = strdup(git_path("logs/%s", lock->ref_file + plen));
+       lock->force_write = !lstat(lock->ref_file, &st) || errno == ENOENT;
 
        if (safe_create_leading_directories(lock->lock_file))
                die("unable to create directory for %s", lock->lock_file);
@@ -405,7 +407,7 @@ int write_ref_sha1(struct ref_lock *lock,
 
        if (!lock)
                return -1;
-       if (!memcmp(lock->old_sha1, sha1, 20)) {
+       if (!lock->force_write && !memcmp(lock->old_sha1, sha1, 20)) {
                unlock_ref(lock);
                return 0;
        }

diff --git a/refs.h b/refs.h
index 2c854de..6c946ea 100644 (file)
--- a/refs.h
+++ b/refs.h
@@ -7,6 +7,7 @@ struct ref_lock {
        char *log_file;
        unsigned char old_sha1[20];
        int lock_fd;
+       int force_write;
 };
 
 /*