Nginx does not know about the DNS names of specified backend servers?

I did already mention this problem in one previous post, still I would like to talk about it one more time because it kind of bothers me.

While writing an Nginx loadbalancer module I discovered that when you define a backend server using the server directive in an upstream block in the config file, even if you specify the upstream by using a DNS name, Nginx doesn't seem to keep the information of the actual DNS name anywhere available. It only keeps the resolved IPs after it did the name resolution once on startup.

The reason why this is a problem in my case is because I write a loadbalancer which should always find exactly the same backend server as the PHP-Memcache module load balancer does. Since the PHP-Memcache loadbalancer decides based on a hash of the actual strings that got passed to the addServer method, it is crucial for my Nginx loadbalancer to be able to do the same. Which means that if somebody in the Nginx config specifies an IP i will have to hash the string of the IP, if somebody enters the hostname of the backend server i will have to hash the hostname.

To make the whole thing work as I wanted I had to do what I really hated to do, I created a DNS supporting and a non-DNS branch of my loadbalancer module on github. While my neckhairs stood on end just by the thought of what I am going to do, I added a patch for the upstream module to the DNS aware branch which doesn't do more than adding a string to the struct ngx_http_upstream_server_t:

typedef struct {
 +    ngx_str_t                        name;
     ngx_addr_t                      *addrs;
     ngx_uint_t                       naddrs;
     ngx_uint_t                       weight;
     ngx_uint_t                       max_fails;
     time_t                           fail_timeout;
 
     unsigned                         down:1;
     unsigned                         backup:1;
 } ngx_http_upstream_server_t;

Plus I added one line to the ngx_http_upstream_server function which stores the DNS name of this backend into the above added ngx_str_t:

+    us->name = u.url;
    us->addrs = u.addrs;
    us->naddrs = u.naddrs;
    us->weight = weight;
    us->max_fails = max_fails;
    us->fail_timeout = fail_timeout;

After applying this patch on the nginx source, it required only minor changes to the loadbalancer module to make it use the DNS names instead of resolved IPs. What I don't understand is why the author of the upstream module decided that he should spare those few bytes and not store the actual DNS names that are specified in the config file.

However, hereby I would like to solicit the author of the upstream module or whoever has the power to do this to add this simple ngx_str_t to the ngx_http_upstream_server_t. Thanks