ZUNIONSTORE overwrites a key after potentially reading it.

carted · Aug 10, 2017 · 004efaf · 004efaf
1 parent 995ba13
commit 004efaf
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Showing 2 changed files with 23 additions and 1 deletion.
diff --git a/cmd_sorted_set.go b/cmd_sorted_set.go
@@ -1153,7 +1153,15 @@ func (m *Miniredis) cmdZunionstore(c *server.Peer, cmd string, args []string) {
 
 	withTx(m, c, func(c *server.Peer, ctx *connCtx) {
 		db := m.db(ctx.selectedDB)
-		db.del(destination, true)
+		deleteDest := true
+		for _, key := range keys {
+			if destination == key {
+				deleteDest = false
+			}
+		}
+		if deleteDest {
+			db.del(destination, true)
+		}
 
 		sset := sortedSet{}
 		for i, key := range keys {

diff --git a/cmd_sorted_set_test.go b/cmd_sorted_set_test.go
@@ -1106,6 +1106,20 @@ func TestZunionstore(t *testing.T) {
 		equals(t, map[string]float64{"field1": 2, "field2": 4}, ss)
 	}
 
+	// Merge destination with itself.
+	{
+		s.ZAdd("h3", 1.0, "field1")
+		s.ZAdd("h3", 3.0, "field3")
+
+		res, err := redis.Int(c.Do("ZUNIONSTORE", "h3", 2, "h1", "h3"))
+		ok(t, err)
+		equals(t, 3, res)
+
+		ss, err := s.SortedSet("h3")
+		ok(t, err)
+		equals(t, map[string]float64{"field1": 2, "field2": 2, "field3": 3}, ss)
+	}
+
 	// WEIGHTS
 	{
 		res, err := redis.Int(c.Do("ZUNIONSTORE", "weighted", 2, "h1", "h2", "WeIgHtS", "4.5", "12"))