Better error message when we are unable to lock the index file

Most of the callers except the one in refs.c use the function to
update the index file.  Among the index writers, everybody
except write-tree dies if they cannot open it for writing.

This gives the function an extra argument, to tell it to die
when it cannot create a new file as the lockfile.

The only caller that does not have to die is write-tree, because
updating the index for the cache-tree part is optional and not
being able to do so does not affect the correctness.  I think we
do not have to be so careful and make the failure into die() the
same way as other callers, but that would be a different patch.

Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 1 insertions, 4 deletions

diff --git a/builtin-mv.c b/builtin-mv.c
index ce8187c1e..a731f8d9c 100644
--- a/builtin-mv.c
+++ b/builtin-mv.c
@@ -72,10 +72,7 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 
 	git_config(git_default_config);
 
-	newfd = hold_lock_file_for_update(&lock_file, get_index_file());
-	if (newfd < 0)
-		die("unable to create new index file");
-
+	newfd = hold_lock_file_for_update(&lock_file, get_index_file(), 1);
 	if (read_cache() < 0)
 		die("index file corrupt");