From ffa007704122a3e4947252f3dbbef3e2be4b6033 Mon Sep 17 00:00:00 2001
From: Oran Agra <oran@redislabs.com>
Date: Tue, 14 Jun 2022 08:48:08 +0300
Subject: [PATCH] Allow ECHO in loading and stale modes (#10853)

I noticed that scripting.tcl uses INFO from within a script and thought it's an
overkill and concluded it's nicer to use another CMD_STALE command,
decided to use ECHO, and then noticed it's not at all allowed in stale mode.
probably overlooked at #6843
---
 src/commands.c           | 2 +-
 src/commands/echo.json   | 2 ++
 tests/unit/scripting.tcl | 8 ++++----
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/commands.c b/src/commands.c
index 7ea796470..d2364b0ab 100644
--- a/src/commands.c
+++ b/src/commands.c
@@ -7175,7 +7175,7 @@ struct redisCommand redisCommandTable[] = {
 /* connection */
 {"auth","Authenticate to the server","O(N) where N is the number of passwords defined for the user","1.0.0",CMD_DOC_NONE,NULL,NULL,COMMAND_GROUP_CONNECTION,AUTH_History,AUTH_tips,authCommand,-2,CMD_NOSCRIPT|CMD_LOADING|CMD_STALE|CMD_FAST|CMD_NO_AUTH|CMD_SENTINEL|CMD_ALLOW_BUSY,ACL_CATEGORY_CONNECTION,.args=AUTH_Args},
 {"client","A container for client connection commands","Depends on subcommand.","2.4.0",CMD_DOC_NONE,NULL,NULL,COMMAND_GROUP_CONNECTION,CLIENT_History,CLIENT_tips,NULL,-2,CMD_SENTINEL,0,.subcommands=CLIENT_Subcommands},
-{"echo","Echo the given string","O(1)","1.0.0",CMD_DOC_NONE,NULL,NULL,COMMAND_GROUP_CONNECTION,ECHO_History,ECHO_tips,echoCommand,2,CMD_FAST,ACL_CATEGORY_CONNECTION,.args=ECHO_Args},
+{"echo","Echo the given string","O(1)","1.0.0",CMD_DOC_NONE,NULL,NULL,COMMAND_GROUP_CONNECTION,ECHO_History,ECHO_tips,echoCommand,2,CMD_LOADING|CMD_STALE|CMD_FAST,ACL_CATEGORY_CONNECTION,.args=ECHO_Args},
 {"hello","Handshake with Redis","O(1)","6.0.0",CMD_DOC_NONE,NULL,NULL,COMMAND_GROUP_CONNECTION,HELLO_History,HELLO_tips,helloCommand,-1,CMD_NOSCRIPT|CMD_LOADING|CMD_STALE|CMD_FAST|CMD_NO_AUTH|CMD_SENTINEL|CMD_ALLOW_BUSY,ACL_CATEGORY_CONNECTION,.args=HELLO_Args},
 {"ping","Ping the server","O(1)","1.0.0",CMD_DOC_NONE,NULL,NULL,COMMAND_GROUP_CONNECTION,PING_History,PING_tips,pingCommand,-1,CMD_FAST|CMD_SENTINEL,ACL_CATEGORY_CONNECTION,.args=PING_Args},
 {"quit","Close the connection","O(1)","1.0.0",CMD_DOC_NONE,NULL,NULL,COMMAND_GROUP_CONNECTION,QUIT_History,QUIT_tips,quitCommand,-1,CMD_ALLOW_BUSY|CMD_NOSCRIPT|CMD_LOADING|CMD_STALE|CMD_FAST|CMD_NO_AUTH,ACL_CATEGORY_CONNECTION},
diff --git a/src/commands/echo.json b/src/commands/echo.json
index a641bd35d..f38d10bc5 100644
--- a/src/commands/echo.json
+++ b/src/commands/echo.json
@@ -7,6 +7,8 @@
         "arity": 2,
         "function": "echoCommand",
         "command_flags": [
+            "LOADING",
+            "STALE",
             "FAST"
         ],
         "acl_categories": [
diff --git a/tests/unit/scripting.tcl b/tests/unit/scripting.tcl
index 6e43ca264..a91eef7e9 100644
--- a/tests/unit/scripting.tcl
+++ b/tests/unit/scripting.tcl
@@ -1599,19 +1599,19 @@ start_server {tags {"scripting"}} {
             } 1 x
         }
         
-        assert_match {*redis_version*} [
+        assert_match {foobar} [
             r eval {#!lua flags=allow-stale,no-writes
-                return redis.call('info','server')
+                return redis.call('echo','foobar')
             } 0
         ]
         
         # Test again with EVALSHA
         set sha [
             r script load {#!lua flags=allow-stale,no-writes
-                return redis.call('info','server')
+                return redis.call('echo','foobar')
             }
         ]
-        assert_match {*redis_version*} [r evalsha $sha 0]
+        assert_match {foobar} [r evalsha $sha 0]
         
         r replicaof no one
         r config set replica-serve-stale-data yes