From 11dc4e59b365d6cd8699604d7d1c1025b6bb6259 Mon Sep 17 00:00:00 2001
From: Binbin <binloveplay1314@qq.com>
Date: Sat, 17 Jul 2021 14:54:06 +0800
Subject: [PATCH] SMOVE only notify dstset when the addition is successful.
 (#9244)

in case dest key already contains the member, the dest key isn't modified, so the command shouldn't invalidate watch.
---
 src/t_set.c             |  2 +-
 tests/unit/type/set.tcl | 22 ++++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/t_set.c b/src/t_set.c
index b58bb6fc0..88c5c7994 100644
--- a/src/t_set.c
+++ b/src/t_set.c
@@ -392,12 +392,12 @@ void smoveCommand(client *c) {
     }
 
     signalModifiedKey(c,c->db,c->argv[1]);
-    signalModifiedKey(c,c->db,c->argv[2]);
     server.dirty++;
 
     /* An extra key has changed when ele was successfully added to dstset */
     if (setTypeAdd(dstset,ele->ptr)) {
         server.dirty++;
+        signalModifiedKey(c,c->db,c->argv[2]);
         notifyKeyspaceEvent(NOTIFY_SET,"sadd",c->argv[2],c->db->id);
     }
     addReply(c,shared.cone);
diff --git a/tests/unit/type/set.tcl b/tests/unit/type/set.tcl
index a12eae5b3..463dc5859 100644
--- a/tests/unit/type/set.tcl
+++ b/tests/unit/type/set.tcl
@@ -828,6 +828,28 @@ start_server {
         lsort [r smembers set{t}]
     } {a b c}
 
+    test "SMOVE only notify dstset when the addition is successful" {
+        r del srcset{t}
+        r del dstset{t}
+
+        r sadd srcset{t} a b
+        r sadd dstset{t} a
+
+        r watch dstset{t}
+
+        r multi
+        r sadd dstset{t} c
+
+        set r2 [redis_client]
+        $r2 smove srcset{t} dstset{t} a
+
+        # The dstset is actually unchanged, multi should success
+        r exec
+        set res [r scard dstset{t}]
+        assert_equal $res 2
+        $r2 close
+    }
+
     tags {slow} {
         test {intsets implementation stress testing} {
             for {set j 0} {$j < 20} {incr j} {