Clarify rationale behind issue redis#43

async.c

@@ -361,17 +361,20 @@ void redisProcessCallbacks(redisAsyncContext *ac) {
         /* Even if the context is subscribed, pending regular callbacks will
          * get a reply before pub/sub messages arrive. */
         if (__redisShiftCallback(&ac->replies,&cb) != REDIS_OK) {
-            // error reply before any callbacks were setup
+            /* A spontaneous reply in a not-subscribed context can only be the
+             * error reply that is sent when a new connection exceeds the
+             * maximum number of allowed connections on the server side. This
+             * is seen as an error instead of a regular reply because the
+             * server closes the connection after sending it. To prevent the
+             * error from being overwritten by an EOF error the connection is
+             * closed here. See issue #43. */
             if ( !(c->flags & REDIS_SUBSCRIBED) && ((redisReply*)reply)->type == REDIS_REPLY_ERROR ) {
                 c->err = REDIS_ERR_OTHER;
-                err_len = strlen(((redisReply*)reply)->str);
-                err_len = err_len < (sizeof(c->errstr)-1) ? err_len : (sizeof(c->errstr)-1);
-                memcpy(c->errstr, ((redisReply*)reply)->str, err_len);
-                c->errstr[err_len] = '\0';
+                snprintf(c->errstr,sizeof(c->errstr),"%s",((redisReply*)reply)->str);
                 __redisAsyncDisconnect(ac);
                 return;
             }
-            /* No more regular callbacks and no errors, the context *must* be subscribed. */ 
+            /* No more regular callbacks and no errors, the context *must* be subscribed. */
             assert(c->flags & REDIS_SUBSCRIBED);
             __redisGetSubscribeCallback(ac,reply,&cb);
         }