From 732232a123e1e61e38babb1c572722bb8a189ba3 Mon Sep 17 00:00:00 2001
From: Shawn Pearce <spearce@spearce.org>
Date: Fri, 19 May 2006 03:29:05 -0400
Subject: 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
--- 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
--- 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;
 };
 
 /*
-- 
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