From 2017407b4d1d19a91af1e7c0b199f2c1775dbaf9 Mon Sep 17 00:00:00 2001
From: Oran Agra <oran@redislabs.com>
Date: Tue, 5 Jan 2021 08:29:20 +0200
Subject: [PATCH] Fix wrong order of key/value in Lua map response (#8266)

When a Lua script returns a map to redis (a feature which was added in
redis 6 together with RESP3), it would have returned the value first and
the key second.

If the client was using RESP2, it was getting them out of order, and if
the client was in RESP3, it was getting a map of value => key.
This was happening regardless of the Lua script using redis.setresp(3)
or not.

This also affects a case where the script was returning a map which it got
from from redis by doing something like: redis.setresp(3); return redis.call()

This fix is a breaking change for redis 6.0 users who happened to rely
on the wrong order (either ones that used redis.setresp(3), or ones that
returned a map explicitly).

This commit also includes other two changes in the tests:
1. The test suite now handles RESP3 maps as dicts rather than nested
   lists
2. Remove some redundant (duplicate) tests from tracking.tcl
---
 src/scripting.c          |  4 ++--
 tests/support/redis.tcl  | 11 +++++------
 tests/unit/scripting.tcl | 24 ++++++++++++++++++++++++
 tests/unit/tracking.tcl  | 19 +++++--------------
 4 files changed, 36 insertions(+), 22 deletions(-)

diff --git a/src/scripting.c b/src/scripting.c
index 6d0bf2349..75604e4d8 100644
--- a/src/scripting.c
+++ b/src/scripting.c
@@ -407,9 +407,9 @@ void luaReplyToRedisReply(client *c, lua_State *lua) {
             lua_pushnil(lua); /* Use nil to start iteration. */
             while (lua_next(lua,-2)) {
                 /* Stack now: table, key, value */
-                luaReplyToRedisReply(c, lua); /* Return value. */
-                lua_pushvalue(lua,-1);        /* Dup key before consuming. */
+                lua_pushvalue(lua,-2);        /* Dup key before consuming. */
                 luaReplyToRedisReply(c, lua); /* Return key. */
+                luaReplyToRedisReply(c, lua); /* Return value. */
                 /* Stack now: table, key. */
                 maplen++;
             }
diff --git a/tests/support/redis.tcl b/tests/support/redis.tcl
index 9eb5b94e2..8eca2ac32 100644
--- a/tests/support/redis.tcl
+++ b/tests/support/redis.tcl
@@ -214,20 +214,19 @@ proc ::redis::redis_multi_bulk_read {id fd} {
 proc ::redis::redis_read_map {id fd} {
     set count [redis_read_line $fd]
     if {$count == -1} return {}
-    set l {}
+    set d {}
     set err {}
     for {set i 0} {$i < $count} {incr i} {
         if {[catch {
-            set t {}
-            lappend t [redis_read_reply $id $fd] ; # key
-            lappend t [redis_read_reply $id $fd] ; # value
-            lappend l $t
+            set k [redis_read_reply $id $fd] ; # key
+            set v [redis_read_reply $id $fd] ; # value
+            dict set d $k $v
         } e] && $err eq {}} {
             set err $e
         }
     }
     if {$err ne {}} {return -code error $err}
-    return $l
+    return $d
 }
 
 proc ::redis::redis_read_line fd {
diff --git a/tests/unit/scripting.tcl b/tests/unit/scripting.tcl
index 0da1eda9f..6fd152594 100644
--- a/tests/unit/scripting.tcl
+++ b/tests/unit/scripting.tcl
@@ -563,6 +563,30 @@ start_server {tags {"scripting"}} {
         } e
         set e
     } {*wrong number*}
+
+    test {Script with RESP3 map} {
+        set expected_dict [dict create field value]
+        set expected_list [list field value]
+
+        # Sanity test for RESP3 without scripts
+        r HELLO 3
+        r hset hash field value
+        set res [r hgetall hash]
+        assert_equal $res $expected_dict
+
+        # Test RESP3 client with script in both RESP2 and RESP3 modes
+        set res [r eval {redis.setresp(3); return redis.call('hgetall', KEYS[1])} 1 hash]
+        assert_equal $res $expected_dict
+        set res [r eval {redis.setresp(2); return redis.call('hgetall', KEYS[1])} 1 hash]
+        assert_equal $res $expected_list
+
+        # Test RESP2 client with script in both RESP2 and RESP3 modes
+        r HELLO 2
+        set res [r eval {redis.setresp(3); return redis.call('hgetall', KEYS[1])} 1 hash]
+        assert_equal $res $expected_list
+        set res [r eval {redis.setresp(2); return redis.call('hgetall', KEYS[1])} 1 hash]
+        assert_equal $res $expected_list
+    }
 }
 
 # Start a new server since the last test in this stanza will kill the
diff --git a/tests/unit/tracking.tcl b/tests/unit/tracking.tcl
index 6f8b46c84..8ed2801e7 100644
--- a/tests/unit/tracking.tcl
+++ b/tests/unit/tracking.tcl
@@ -132,31 +132,22 @@ start_server {tags {"tracking"}} {
 
     test {HELLO 3 reply is correct} {
         set reply [r HELLO 3]
-        assert {[lindex $reply 2] eq {proto 3}}
+        assert_equal [dict get $reply proto] 3
     }
 
     test {HELLO without protover} {
         set reply [r HELLO 3]
-        assert {[lindex $reply 2] eq {proto 3}}
+        assert_equal [dict get $reply proto] 3
 
         set reply [r HELLO]
-        assert {[lindex $reply 2] eq {proto 3}}
-
-        set reply [r HELLO]
-        assert {[lindex $reply 2] eq {proto 3}}
+        assert_equal [dict get $reply proto] 3
 
         set reply [r HELLO 2]
-        assert {[lindex $reply 4] eq "proto"}
-        assert {[lindex $reply 5] eq 2}
+        assert_equal [dict get $reply proto] 2
 
         set reply [r HELLO]
-        assert {[lindex $reply 4] eq "proto"}
-        assert {[lindex $reply 5] eq 2}
+        assert_equal [dict get $reply proto] 2
 
-        set reply [r HELLO]
-        assert {[lindex $reply 4] eq "proto"}
-        assert {[lindex $reply 5] eq 2}
-        
         # restore RESP3 for next test
         r HELLO 3
     }