Avoid errors and warnings when attempting to do I/O on zero bytes

diff --git a/sha1_file.c b/sha1_file.c
index 53e25f278c6193860431f63a3c9de97f4e347f27..18dd89b50a23a4a99b51d8e99d0c67cace2a1a2d 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -1620,6 +1620,8 @@ static int write_buffer(int fd, const void *buf, size_t len)
 {
        ssize_t size;
 
+       if (!len)
+               return 0;
        size = write_in_full(fd, buf, len);
        if (!size)
                return error("file write: disk full");