From de79a2ee12ef0e301d05494d64831bc407ba3696 Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Wed, 1 Feb 2012 17:05:45 +0100
Subject: [PATCH] Make SORT BY <constant> STORE ... to always produce the same
 output by force sorting, so that we have deterministic replication of this
 command.

---
 src/sort.c          | 9 +++++++++
 tests/unit/sort.tcl | 7 +++++++
 2 files changed, 16 insertions(+)

diff --git a/src/sort.c b/src/sort.c
index 11b73ad3..3f02e49a 100644
--- a/src/sort.c
+++ b/src/sort.c
@@ -203,6 +203,15 @@ void sortCommand(redisClient *c) {
         j++;
     }
 
+    /* If we have STORE we need to force sorting for deterministic output
+     * and replication. We use alpha sorting since this is guaranteed to
+     * work with any input. */
+    if (storekey && dontsort) {
+        dontsort = 0;
+        alpha = 1;
+        sortby = NULL;
+    }
+
     /* Destructively convert encoded sorted sets for SORT. */
     if (sortval->type == REDIS_ZSET)
         zsetConvert(sortval, REDIS_ENCODING_SKIPLIST);
diff --git a/tests/unit/sort.tcl b/tests/unit/sort.tcl
index a50f0473..20eec44b 100644
--- a/tests/unit/sort.tcl
+++ b/tests/unit/sort.tcl
@@ -157,6 +157,13 @@ start_server {
         r exists foo
     } {0}
 
+    test "SORT with BY <constant> and STORE should still order output" {
+        r del myset mylist
+        r sadd myset a b c d e f g h i l m n o p q r s t u v z
+        r sort myset alpha by _ store mylist
+        r lrange mylist 0 -1
+    } {a b c d e f g h i l m n o p q r s t u v z}
+
     tags {"slow"} {
         set num 100
         set res [create_random_dataset $num lpush]
-- 
2.45.2