From 6201f7b4e0cb1ee96f54d6ec5b993d422581fbf9 Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Tue, 17 Jul 2018 17:54:10 +0200
Subject: [PATCH] Streams: better error when $ is given with XREADGROUP.

---
 src/t_stream.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/t_stream.c b/src/t_stream.c
index 05de288e..201509c7 100644
--- a/src/t_stream.c
+++ b/src/t_stream.c
@@ -1352,8 +1352,11 @@ void xreadCommand(client *c) {
 
         if (strcmp(c->argv[i]->ptr,"$") == 0) {
             if (xreadgroup) {
-                addReplyError(c,"The $ ID can be specified only when calling "
-                              "XREAD without GROUP option.");
+                addReplyError(c,"The $ ID is meaningless in the context of "
+                                "XREADGROUP: you want to read the history of "
+                                "this consumer by specifying a proper ID, or "
+                                "use the > ID to get new messages. The $ ID would "
+                                "just return an empty result set.");
                 goto cleanup;
             }
             if (o) {